Network Working Group
Request for Comments: 2911
Obsoletes: 2566
Category: Standards Track

T. Hastings, Editor
R. Herriot
Xerox Corporation
R. deBry
Utah Valley State College
S. Isaacson
Novell, Inc.
P. Powell
Astart Technologies
September 2000

Internet Printing Protocol/1.1: Model and Semantics

Status of this Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Abstract

This document is one of a set of documents, which together describe all aspects of a new Internet Printing Protocol (IPP). IPP is an application level protocol that can be used for distributed printing using Internet tools and technologies. This document describes a simplified model consisting of abstract objects, their attributes, and their operations that is independent of encoding and transport. The model consists of a Printer and a Job object. A Job optionally supports multiple documents. IPP 1.1 semantics allow end-users and operators to query printer capabilities, submit print jobs, inquire about the status of print jobs and printers, cancel, hold, release, and restart print jobs. IPP 1.1 semantics allow operators to pause, resume, and purge (jobs from) Printer objects. This document also addresses security, internationalization, and directory issues.

The full set of IPP documents includes:

Design Goals for an Internet Printing Protocol [RFC2567] Rationale for the Structure and Model and Protocol for the Internet Printing Protocol [RFC2568]
Internet Printing Protocol/1.1: Model and Semantics (this document) Internet Printing Protocol/1.1: Encoding and Transport [RFC2910] Internet Printing Protocol/1.1: Implementer's Guide [IPP-IIG] Mapping between LPD and IPP Protocols [RFC2569]

The "Design Goals for an Internet Printing Protocol" document takes a broad look at distributed printing functionality, and it enumerates real-life scenarios that help to clarify the features that need to be included in a printing protocol for the Internet. It identifies requirements for three types of users: end users, operators, and administrators. It calls out a subset of end user requirements that are satisfied in IPP/1.0. A few OPTIONAL operator operations have been added to IPP/1.1.

The "Rationale for the Structure and Model and Protocol for the Internet Printing Protocol" document describes IPP from a high level view, defines a roadmap for the various documents that form the suite of IPP specification documents, and gives background and rationale for the IETF working group's major decisions.

The "Internet Printing Protocol/1.1: Encoding and Transport" document is a formal mapping of the abstract operations and attributes defined in the model document onto HTTP/1.1 [RFC2616]. It defines the encoding rules for a new Internet MIME media type called "application/ipp". This document also defines the rules for transporting over HTTP a message body whose Content-Type is "application/ipp". This document defines a new scheme named 'ipp' for identifying IPP printers and jobs.

The "Internet Printing Protocol/1.1: Implementer's Guide" document gives insight and advice to implementers of IPP clients and IPP objects. It is intended to help them understand IPP/1.1 and some of the considerations that may assist them in the design of their client and/or IPP object implementations. For example, a typical order of processing requests is given, including error checking. Motivation for some of the specification decisions is also included.

The "Mapping between LPD and IPP Protocols" document gives some advice to implementers of gateways between IPP and LPD (Line Printer Daemon) implementations.

   1.   Introduction                                                 9
   1.1   Simplified Printing Model                                  10
   2.   IPP Objects                                                 12
   2.1   Printer Object                                             13
   2.2   Job Object                                                 15
   2.3   Object Relationships                                       16
   2.4   Object Identity                                            17
   3.   IPP Operations                                              20
   3.1   Common Semantics                                           21
   3.1.1  Required Parameters                                       21
   3.1.2  Operation IDs and Request IDs                             22
   3.1.3  Attributes                                                22
   3.1.4  Character Set and Natural Language Operation Attribute    24
   3.1.4.1   Request Operation Attributes                           25
   3.1.4.2   Response Operation Attributes                          29
   3.1.5  Operation Targets                                         30
   3.1.6  Operation Response Status Codes and Status Messages       32
   3.1.6.1   "status-code" (type2 enum)                             32
   3.1.6.2   "status-message" (text(255))                           33
   3.1.6.3   "detailed-status-message" (text(MAX))                  33
   3.1.6.4   "document-access-error" (text(MAX))                    34
   3.1.7  Unsupported Attributes                                    34
   3.1.8  Versions                                                  36
   3.1.9  Job Creation Operations                                   38
   3.2   Printer Operations                                         41
   3.2.1  Print-Job Operation                                       41
   3.2.1.1   Print-Job Request                                      41
   3.2.1.2   Print-Job Response                                     46
   3.2.2  Print-URI Operation                                       48
   3.2.3  Validate-Job Operation                                    49
   3.2.4  Create-Job Operation                                      49
   3.2.5  Get-Printer-Attributes Operation                          50
   3.2.5.1   Get-Printer-Attributes Request                         51
   3.2.5.2   Get-Printer-Attributes Response                        53
   3.2.6  Get-Jobs Operation                                        54
   3.2.6.1   Get-Jobs Request                                       54
   3.2.6.2   Get-Jobs Response                                      56
   3.2.7  Pause-Printer Operation                                   57
   3.2.7.1   Pause-Printer Request                                  59
   3.2.7.2   Pause-Printer Response                                 60
   3.2.8  Resume-Printer Operation                                  60
   3.2.9  Purge-Jobs Operation                                      61
   3.3   Job Operations                                             62
   3.3.1  Send-Document Operation                                   62
   3.3.1.1   Send-Document Request                                  64
   3.3.1.2   Send-Document Response                                 65
   
   3.3.2  Send-URI Operation                                        66
   3.3.3  Cancel-Job Operation                                      66
   3.3.3.1   Cancel-Job Request                                     67
   3.3.3.2   Cancel-Job Response                                    68
   3.3.4  Get-Job-Attributes Operation                              69
   3.3.4.1   Get-Job-Attributes Request                             69
   3.3.4.2   Get-Job-Attributes Response                            70
   3.3.5  Hold-Job Operation                                        71
   3.3.5.1   Hold-Job Request                                       72
   3.3.5.2   Hold-Job Response                                      73
   3.3.6  Release-Job Operation                                     74
   3.3.7  Restart-Job Operation                                     75
   3.3.7.1   Restart-Job Request                                    76
   3.3.7.2   Restart-Job Response                                   78
   4.   Object Attributes                                           78
   4.1   Attribute Syntaxes                                         78
   4.1.1  'text'                                                    79
   4.1.1.1   'textWithoutLanguage'                                  80
   4.1.1.2   'textWithLanguage'                                     80
   4.1.2  'name'                                                    81
   4.1.2.1   'nameWithoutLanguage'                                  82
   4.1.2.2   'nameWithLanguage'                                     82
   4.1.2.3   Matching 'name' attribute values                       83
   4.1.3  'keyword'                                                 84
   4.1.4  'enum'                                                    85
   4.1.5  'uri'                                                     85
   4.1.6  'uriScheme'                                               86
   4.1.7  'charset'                                                 86
   4.1.8  'naturalLanguage'                                         87
   4.1.9  'mimeMediaType'                                           87
   4.1.9.1 Application/octet-stream -- Auto-Sensing                 88
           the document format
   4.1.10 'octetString'                                             89
   4.1.11 'boolean'                                                 89
   4.1.12 'integer'                                                 89
   4.1.13 'rangeOfInteger'                                          90
   4.1.14 'dateTime'                                                90
   4.1.15 'resolution'                                              90
   4.1.16 '1setOf  X'                                               90
   4.2   Job Template Attributes                                    91
   4.2.1  job-priority (integer(1:100))                             94
   4.2.2  job-hold-until (type3 keyword | name (MAX))               95
   4.2.3  job-sheets (type3 keyword | name(MAX))                    96
   4.2.4  multiple-document-handling (type2 keyword)                96
   4.2.5  copies (integer(1:MAX))                                   98
   4.2.6  finishings (1setOf type2 enum)                            98
   4.2.7  page-ranges (1setOf rangeOfInteger (1:MAX))              101
   4.2.8  sides (type2 keyword)                                    102
   4.2.9  number-up (integer(1:MAX))                               102
   4.2.10 orientation-requested (type2 enum)                       103
   4.2.11 media (type3 keyword | name(MAX))                        104
   4.2.12 printer-resolution (resolution)                          105
   4.2.13 print-quality (type2 enum)                               105
   4.3   Job Description Attributes                                106
   4.3.1  job-uri (uri)                                            107
   4.3.2  job-id (integer(1:MAX))                                  108
   4.3.3  job-printer-uri (uri)                                    108
   4.3.4  job-more-info (uri)                                      108
   4.3.5  job-name (name(MAX))                                     108
   4.3.6  job-originating-user-name (name(MAX))                    109
   4.3.7  job-state (type1 enum)                                   109
   4.3.7.1   Forwarding Servers                                    112
   4.3.7.2   Partitioning of Job States                            112
   4.3.8  job-state-reasons (1setOf  type2 keyword)                113
   4.3.9  job-state-message (text(MAX))                            118
   4.3.10 job-detailed-status-messages (1setOf text(MAX))          118
   4.3.11 job-document-access-errors (1setOf text(MAX))            118
   4.3.12 number-of-documents (integer(0:MAX))                     119
   4.3.13 output-device-assigned (name(127))                       119
   4.3.14 Event Time Job Description Attributes                    119
   4.3.14.1  time-at-creation (integer(MIN:MAX))                   120
   4.3.14.2  time-at-processing (integer(MIN:MAX))                 120
   4.3.14.3  time-at-completed (integer(MIN:MAX))                  120
   4.3.14.4  job-printer-up-time (integer(1:MAX))                  120
   4.3.14.5  date-time-at-creation (dateTime)                      121
   4.3.14.6  date-time-at-processing (dateTime)                    121
   4.3.14.7  date-time-at-completed (dateTime)                     121
   4.3.15 number-of-intervening-jobs (integer(0:MAX))              121
   4.3.16 job-message-from-operator (text(127))                    121
   4.3.17 Job Size Attributes                                      121
   4.3.17.1  job-k-octets (integer(0:MAX))                         122
   4.3.17.2  job-impressions (integer(0:MAX))                      122
   4.3.17.3  job-media-sheets (integer(0:MAX))                     123
   4.3.18 Job Progress Attributes                                  123
   4.3.18.1  job-k-octets-processed (integer(0:MAX))               123
   4.3.18.2  job-impressions-completed (integer(0:MAX))            123
   4.3.18.3  job-media-sheets-completed (integer(0:MAX))           124
   4.3.19 attributes-charset (charset)                             124
   4.3.20 attributes-natural-language (naturalLanguage)            124
   4.4   Printer Description Attributes                            124
   4.4.1  printer-uri-supported (1setOf uri)                       126
   4.4.2  uri-authentication-supported (1setOf type2 keyword)      127
   4.4.3  uri-security-supported (1setOf type2 keyword)            128
   4.4.4  printer-name (name(127))                                 129
   4.4.5  printer-location (text(127))                             129
   4.4.6  printer-info (text(127))                                 130
   4.4.7  printer-more-info (uri)                                  130
   4.4.8  printer-driver-installer (uri)                           130
   4.4.9  printer-make-and-model (text(127))                       130
   4.4.10 printer-more-info-manufacturer (uri)                     130
   4.4.11 printer-state (type1 enum)                               131
   4.4.12 printer-state-reasons (1setOf type2 keyword)             131
   4.4.13 printer-state-message (text(MAX))                        134
   4.4.14 ipp-versions-supported (1setOf type2 keyword)            134
   4.4.15 operations-supported (1setOf type2 enum)                 135
   4.4.16 multiple-document-jobs-supported (boolean)               136
   4.4.17 charset-configured (charset)                             136
   4.4.18 charset-supported (1setOf charset)                       137
   4.4.19 natural-language-configured (naturalLanguage)            137
   4.4.20 generated-natural-language-supported
          (1setOf naturalLanguage)                                 137
   4.4.21 document-format-default (mimeMediaType)                  138
   4.4.22 document-format-supported (1setOf mimeMediaType)         138
   4.4.23 printer-is-accepting-jobs (boolean)                      138
   4.4.24 queued-job-count (integer(0:MAX))                        138
   4.4.25 printer-message-from-operator (text(127))                139
   4.4.26 color-supported (boolean)                                139
   4.4.27 reference-uri-schemes-supported (1setOf uriScheme)       139
   4.4.28 pdl-override-supported (type2 keyword)                   139
   4.4.29 printer-up-time (integer(1:MAX))                         140
   4.4.30 printer-current-time (dateTime)                          140
   4.4.31 multiple-operation-time-out (integer(1:MAX))             141
   4.4.32 compression-supported (1setOf type3 keyword)             141
   4.4.33 job-k-octets-supported (rangeOfInteger(0:MAX))           142
   4.4.34 job-impressions-supported (rangeOfInteger(0:MAX))        142
   4.4.35 job-media-sheets-supported (rangeOfInteger(0:MAX))       142
   4.4.36 pages-per-minute (integer(0:MAX))                        142
   4.4.37 pages-per-minute-color (integer(0:MAX))                  142
   5.   Conformance                                                143
   5.1   Client Conformance Requirements                           143
   5.2   IPP Object Conformance Requirements                       145
   5.2.1  Objects                                                  145
   5.2.2  Operations                                               145
   5.2.3  IPP Object Attributes                                    146
   5.2.4  Versions                                                 146
   5.2.5  Extensions                                               147
   5.2.6  Attribute Syntaxes                                       147
   5.2.7  Security                                                 148
   5.3   Charset and Natural Language Requirements                 148
   6.   IANA Considerations                                        148
   6.1   Typed 'keyword' and 'enum' Extensions                     149
   6.2   Attribute Extensibility                                   151
   6.3   Attribute Syntax Extensibility                            152
   6.4   Operation Extensibility                                   152
   6.5   Attribute Group Extensibility                             153
   6.6   Status Code Extensibility                                 153
   6.7   Out-of-band Attribute Value Extensibility                 154
   6.8   Registration of MIME types/sub-types for document-formats 154
   6.9   Registration of charsets for use in 'charset'
         attribute values                                          154
   7.   Internationalization Considerations                        154
   8.   Security Considerations                                    158
   8.1   Security Scenarios                                        159
   8.1.1  Client and Server in the Same Security Domain            159
   8.1.2  Client and Server in Different Security Domains          159
   8.1.3  Print by Reference                                       160
   8.2   URIs in Operation, Job, and Printer attributes            160
   8.3   URIs for each authentication mechanisms                   160
   8.4   Restricted Queries                                        161
   8.5   Operations performed by operators and system
         administrators                                            161
   8.6   Queries on jobs submitted using non-IPP protocols         162
   9.   References                                                 162
   10.  Authors' Addresses                                         166
   11.  Formats for IPP Registration Proposals                     168
   11.1  Type2 keyword attribute values registration               169
   11.2  Type3 keyword attribute values registration               169
   11.3  Type2 enum attribute values registration                  169
   11.4  Type3 enum attribute values registration                  170
   11.5  Attribute registration                                    170
   11.6  Attribute Syntax registration                             171
   11.7  Operation registration                                    171
   11.8  Attribute Group registration                              171
   11.9  Status code registration                                  172
   11.10 Out-of-band Attribute Value registration                  172
   12.  APPENDIX A: Terminology                                    173
   12.1  Conformance Terminology                                   173
   12.1.1 NEED NOT                                                 173
   12.2  Model Terminology                                         173
   12.2.1 Keyword                                                  173
   12.2.2 Attributes                                               173
   12.2.2.1  Attribute Name                                        173
   12.2.2.2  Attribute Group Name                                  174
   12.2.2.3  Attribute Value                                       174
   12.2.2.4  Attribute Syntax                                      174
   12.2.3 Supports                                                 174
   12.2.4 print-stream page                                        176
   12.2.5 impression                                               177
   13. APPENDIX B: Status Codes and Suggested Status Code Messages 177
   13.1  Status Codes                                              178
   13.1.1 Informational                                            178
   13.1.2 Successful Status Codes                                  178
   13.1.2.1  successful-ok (0x0000)                                178
   13.1.2.2  successful-ok-ignored-or-substituted-attributes
             (0x0001)                                              179
   13.1.2.3  successful-ok-conflicting-attributes (0x0002)         179
   13.1.3 Redirection Status Codes                                 179
   13.1.4 Client Error Status Codes                                179
   13.1.4.1  client-error-bad-request (0x0400)                     180
   13.1.4.2  client-error-forbidden (0x0401)                       180
   13.1.4.3  client-error-not-authenticated (0x0402)               180
   13.1.4.4  client-error-not-authorized (0x0403)                  180
   13.1.4.5  client-error-not-possible (0x0404)                    180
   13.1.4.6  client-error-timeout (0x0405)                         181
   13.1.4.7  client-error-not-found (0x0406)                       181
   13.1.4.8  client-error-gone (0x0407)                            181
   13.1.4.9  client-error-request-entity-too-large (0x0408)        182
   13.1.4.10 client-error-request-value-too-long (0x0409)          182
   13.1.4.11 client-error-document-format-not-supported (0x040A)   182
   13.1.4.12 client-error-attributes-or-values-not-supported
             (0x040B)                                              183
   13.1.4.13 client-error-uri-scheme-not-supported (0x040C)        183
   13.1.4.14 client-error-charset-not-supported (0x040D)           183
   13.1.4.15 client-error-conflicting-attributes (0x040E)          183
   13.1.4.16 client-error-compression-not-supported (0x040F)       184
   13.1.4.17 client-error-compression-error (0x0410)               184
   13.1.4.18 client-error-document-format-error (0x0411)           184
   13.1.4.19 client-error-document-access-error (0x0412)           184
   13.1.5    Server Error Status Codes                             185
   13.1.5.1  server-error-internal-error (0x0500)                  185
   13.1.5.2  server-error-operation-not-supported (0x0501)         185
   13.1.5.3  server-error-service-unavailable (0x0502)             185
   13.1.5.4  server-error-version-not-supported (0x0503)           185
   13.1.5.5  server-error-device-error (0x0504)                    186
   13.1.5.6  server-error-temporary-error (0x0505)                 186
   13.1.5.7  server-error-not-accepting-jobs (0x0506)              187
   13.1.5.8  server-error-busy (0x0507)                            187
   13.1.5.9  server-error-job-canceled (0x0508)                    187
   13.1.5.10 server-error-multiple-document-jobs-not-supported
             (0x0509)                                              187
   13.2  Status Codes for IPP Operations                           187
   14.  APPENDIX C:  "media" keyword values                        190
   15.  APPENDIX D: Processing IPP Attributes                      208
   15.1  Fidelity                                                  209
   15.2  Page Description Language (PDL) Override                  210
   15.3  Using Job Template Attributes During Document Processing  212
   16.  APPENDIX E: Generic Directory Schema                       214
   17.  APPENDIX F:  Differences between the IPP/1.0 and IPP/1.1
        "Model and Semantics" Documents                            215
   18.  Full Copyright Statement                                   224

1. Introduction

The Internet Printing Protocol (IPP) is an application level protocol that can be used for distributed printing using Internet tools and technologies. IPP version 1.1 (IPP/1.1) focuses primarily on end user functionality with a few administrative operations included. This document is just one of a suite of documents that fully define IPP. The full set of IPP documents includes:

Anyone reading these documents for the first time is strongly encouraged to read the IPP documents in the above order.

This document is laid out as follows:

   - The rest of Section 1 is an introduction to the IPP simplified
     model for distributed printing.
   - Section 2 introduces the object types covered in the model with
     their basic behaviors, attributes, and interactions.
   - Section 3 defines the operations included in IPP/1.1.  IPP
     operations are synchronous, therefore, for each operation, there is
     a both request and a response.
   - Section 4 defines the attributes (and their syntaxes) that are used
     in the model.
   - Sections 5 - 6 summarizes the implementation conformance
     requirements for objects that support the protocol and IANA
     considerations, respectively.
   - Sections 7 - 11 cover the Internationalization and Security
     considerations as well as References, Author contact information,
     and Formats for Registration Proposals.
   - Sections 12 - 14 are appendices that cover Terminology, Status
     Codes and Messages, and "media" keyword values.

Note: This document uses terms such as "attributes", "keywords", and "support". These terms have special meaning and are defined in the model terminology section 12.2. Capitalized terms, such as MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, MAY, NEED NOT, and OPTIONAL, have special meaning relating to conformance. These terms are defined in section 12.1 on conformance terminology, most of which is taken from RFC 2119 [RFC2119].

   - Section 15 is an appendix that helps to clarify the effects of
     interactions between related attributes and their values.
   - Section 16 is an appendix that enumerates the subset of Printer
     attributes that form a generic directory schema.  These attributes
     are useful when registering a Printer so that a client can find the
     Printer not just by name, but by filtered searches as well.
   - Section 17 is an appendix summarizing the additions and changes
     from the IPP/1.0 "Model and Semantics" document [RFC2566] to make
     this IPP/1.1 document.
   - Section 18 is the full copyright notice.

1.1 Simplified Printing Model

In order to achieve its goal of realizing a workable printing protocol for the Internet, the Internet Printing Protocol (IPP) is based on a simplified printing model that abstracts the many components of real world printing solutions. The Internet is a distributed computing environment where requesters of print services (clients, applications, printer drivers, etc.) cooperate and interact with print service providers. This model and semantics document describes a simple, abstract model for IPP even though the underlying configurations may be complex "n-tier" client/server systems. An important simplifying step in the IPP model is to expose only the key objects and interfaces required for printing. The model described in this model document does not include features, interfaces, and relationships that are beyond the scope of the first version of IPP (IPP/1.1). IPP/1.1 incorporates many of the relevant ideas and lessons learned from other specification and development efforts [HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP]. IPP is heavily influenced by the printing model introduced in the Document Printing Application (DPA) [ISO10175] standard. Although DPA specifies both end user and administrative features, IPP version 1.1 (IPP/1.1) focuses primarily on end user functionality with a few additional OPTIONAL operator operations.

The IPP/1.1 model encapsulates the important components of distributed printing into two object types:

      - Printer (Section 2.1)
      - Job (Section 2.2)

Each object type has an associated set of operations (see section 3) and attributes (see section 4).

It is important, however, to understand that in real system implementations (which lie underneath the abstracted IPP/1.1 model), there are other components of a print service which are not explicitly defined in the IPP/1.1 model. The following figure illustrates where IPP/1.1 fits with respect to these other components.

                                +--------------+
                                |  Application |
                      o         +. . . . . . . |
                     \|/        |   Spooler    |
                     / \        +. . . . . . . |   +---------+
                   End-User     | Print Driver |---|  File   |
         +-----------+ +-----+  +------+-------+   +----+----+
         |  Browser  | | GUI |         |                |
         +-----+-----+ +--+--+         |                |
               |          |            |                |
               |      +---+------------+---+            |
   N   D   S   |      |      IPP Client    |------------+
   O   I   E   |      +---------+----------+
   T   R   C   |                |
   I   E   U   |
   F   C   R   -------------- Transport ------------------
   I   T   I
   C   O   T                    |         --+
   A   R   Y           +--------+--------+  |
   T   Y               |    IPP Server   |  |
   I                   +--------+--------+  |
   O                            |           |
   N                   +-----------------+  | IPP Printer
                       |  Print Service  |  |
                       +-----------------+  |
                                |         --+
                       +-----------------+
                       | Output Device(s)|
                       +-----------------+

An IPP Printer object encapsulates the functions normally associated with physical output devices along with the spooling, scheduling and multiple device management functions often associated with a print server. Printer objects are optionally registered as entries in a directory where end users find and select them based on some sort of filtered and context based searching mechanism (see section 16). The directory is used to store relatively static information about the Printer, allowing end users to search for and find Printers that match their search criteria, for example: name, context, printer capabilities, etc. The more dynamic information, such as state, currently loaded and ready media, number of jobs at the Printer, errors, warnings, and so forth, is directly associated with the Printer object itself rather than with the entry in the directory which only represents the Printer object.

IPP clients implement the IPP protocol on the client side and give end users (or programs running on behalf of end users) the ability to query Printer objects and submit and manage print jobs. An IPP server is just that part of the Printer object that implements the server-side protocol. The rest of the Printer object implements (or gateways into) the application semantics of the print service itself. The Printer objects may be embedded in an output device or may be implemented on a host on the network that communicates with an output device.

When a job is submitted to the Printer object and the Printer object validates the attributes in the submission request, the Printer object creates a new Job object. The end user then interacts with this new Job object to query its status and monitor the progress of the job. An end user can also cancel their print jobs by using the Job object's Cancel-Job operation. An end-user can also hold, release, and restart their print jobs using the Job object's OPTIONAL Hold-Job, Release-Job, and Restart-Job operations, if implemented.

A privileged operator or administrator of a Printer object can cancel, hold, release, and restart any user's job using the REQUIRED Cancel-Job and the OPTIONAL Hold-Job, Release-Job, and Restart-Job operations. In additional privileged operator or administrator of a Printer object can pause, resume, or purge (jobs from) a Printer object using the OPTIONAL Pause-Printer, Resume-Printer, and Purge- Jobs operations, if implemented.

The notification service is out of scope for this IPP/1.1 document, but using such a notification service, the end user is able to register for and receive Printer specific and Job specific events. An end user can query the status of Printer objects and can follow the progress of Job objects by polling using the Get-Printer- Attributes, Get-Jobs, and Get-Job-Attributes operations.

2. IPP Objects

The IPP/1.1 model introduces objects of type Printer and Job. Each type of object models relevant aspects of a real-world entity such as a real printer or real print job. Each object type is defined as a set of possible attributes that may be supported by instances of that object type. For each object (instance), the actual set of supported attributes and values describe a specific implementation. The object's attributes and values describe its state, capabilities, realizable features, job processing functions, and default behaviors and characteristics. For example, the Printer object type is defined as a set of attributes that each Printer object potentially supports. In the same manner, the Job object type is defined as a set of attributes that are potentially supported by each Job object.

Each attribute included in the set of attributes defining an object type is labeled as:

- "REQUIRED": each object MUST support the attribute. - "RECOMMENDED": each object SHOULD support the attribute. - "OPTIONAL": each object MAY support the attribute.

Some definitions of attribute values indicate that an object MUST or SHOULD support the value; otherwise, support of the value is OPTIONAL.

However, if an implementation supports an attribute, it MUST support at least one of the possible values for that attribute.

2.1 Printer Object

The major component of the IPP/1.1 model is the Printer object. A Printer object implements the server-side of the IPP/1.1 protocol. Using the protocol, end users may query the attributes of the Printer object and submit print jobs to the Printer object. The actual implementation components behind the Printer abstraction may take on different forms and different configurations. However, the model abstraction allows the details of the configuration of real components to remain opaque to the end user. Section 3 describes each of the Printer operations in detail.

The capabilities and state of a Printer object are described by its attributes. Printer attributes are divided into two groups:

   - "job-template" attributes: These attributes describe supported job
     processing capabilities and defaults for the Printer object. (See
     section 4.2)
   - "printer-description" attributes: These attributes describe the
     Printer object's identification, state, location, references to
     other sources of information about the Printer object, etc. (see
     section 4.4)

Since a Printer object is an abstraction of a generic document output device and print service provider, a Printer object could be used to represent any real or virtual device with semantics consistent with the Printer object, such as a fax device, an imager, or even a CD writer.

Some examples of configurations supporting a Printer object include:

1) An output device with no spooling capabilities
2) An output device with a built-in spooler
3) A print server supporting IPP with one or more associated

         output devices
         3a) The associated output devices may or may not be capable of
             spooling jobs
         3b) The associated output devices may or may not support IPP

The following figures show some examples of how Printer objects can be realized on top of various distributed printing configurations. The embedded case below represents configurations 1 and 2. The hosted and fan-out figures below represent configurations 3a and 3b.

In this document the term "client" refers to a software entity that sends IPP operation requests to an IPP Printer object and accepts IPP operation responses. A client MAY be:

contained within software controlled by an end user, e.g. activated by the "Print" menu item in an application or

the print server component that sends IPP requests to either an output device or another "downstream" print server.

The term "IPP Printer" is a network entity that accepts IPP operation requests and returns IPP operation responses. As such, an IPP object MAY be:

an (embedded) device component that accepts IPP requests and controls the device or

a component of a print server that accepts IPP requests (where the print server controls one or more networked devices using IPP or other protocols).

Legend:

##### indicates a Printer object which is

either embedded in an output device or is
hosted in a server. The Printer object
might or might not be capable of queuing/spooling.

   any   indicates any network protocol or direct
         connect, including IPP
   
   embedded printer:
                                             output device
                                           +---------------+
    O   +--------+                         |  ###########  |
   /|\  | client |------------IPP------------># Printer #  |
   / \  +--------+                         |  # Object  #  |
                                           |  ###########  |
                                           +---------------+
   
   hosted printer:
                                           +---------------+
    O   +--------+        ###########      |               |
   /|\  | client |--IPP--># Printer #-any->| output device |
   / \  +--------+        # Object  #      |               |
                          ###########      +---------------+
   
                                            +---------------+
   fan out:                                 |               |
                                        +-->| output device |
                                    any/    |               |
    O   +--------+      ###########   /     +---------------+
   /|\  | client |-IPP-># Printer #--*
   / \  +--------+      # Object  #   \     +---------------+
                        ########### any\    |               |
                                        +-->| output device |
                                            |               |
                                            +---------------+

2.2 Job Object

A Job object is used to model a print job. A Job object contains documents. The information required to create a Job object is sent in a create request from the end user via an IPP Client to the Printer object. The Printer object validates the create request, and if the Printer object accepts the request, the Printer object creates the new Job object. Section 3 describes each of the Job operations in detail.

The characteristics and state of a Job object are described by its attributes. Job attributes are grouped into two groups as follows:

"job-template" attributes: These attributes can be supplied by the client or end user and include job processing instructions which are intended to override any Printer object defaults and/or instructions embedded within the document data. (See section 4.2)

"job-description" attributes: These attributes describe the Job object's identification, state, size, etc. The client supplies some of these attributes, and the Printer object generates others. (See section 4.3)

An implementation MUST support at least one document per Job object. An implementation MAY support multiple documents per Job object. A document is either:

      - a stream of document data in a format supported by the Printer
        object (typically a Page Description Language - PDL), or
      - a reference to such a stream of document data

In IPP/1.1, a document is not modeled as an IPP object, therefore it has no object identifier or associated attributes. All job processing instructions are modeled as Job object attributes. These attributes are called Job Template attributes and they apply equally to all documents within a Job object.

2.3 Object Relationships

IPP objects have relationships that are maintained persistently along with the persistent storage of the object attributes.

A Printer object can represent either one or more physical output devices or a logical device which "processes" jobs but never actually uses a physical output device to put marks on paper. Examples of logical devices include a Web page publisher or a gateway into an online document archive or repository. A Printer object contains zero or more Job objects.

A Job object is contained by exactly one Printer object, however the identical document data associated with a Job object could be sent to either the same or a different Printer object. In this case, a second Job object would be created which would be almost identical to the first Job object, however it would have new (different) Job object identifiers (see section 2.4).

A Job object is either empty (before any documents have been added) or contains one or more documents. If the contained document is a stream of document data, that stream can be contained in only one document. However, there can be identical copies of the stream in other documents in the same or different Job objects. If the contained document is just a reference to a stream of document data, other documents (in the same or different Job object(s)) may contain the same reference.

2.4 Object Identity

All Printer and Job objects are identified by a Uniform Resource Identifier (URI) [RFC2396] so that they can be persistently and unambiguously referenced. Since every URL is a specialized form of a URI, even though the more generic term URI is used throughout the rest of this document, its usage is intended to cover the more specific notion of URL as well.

An administrator configures Printer objects to either support or not support authentication and/or message privacy using Transport Layer Security (TLS) [RFC2246] (the mechanism for security configuration is outside the scope of this IPP/1.1 document). In some situations, both types of connections (both authenticated and unauthenticated) can be established using a single communication channel that has some sort of negotiation mechanism. In other situations, multiple communication channels are used, one for each type of security configuration. Section 8 provides a full description of all security considerations and configurations.

If a Printer object supports more than one communication channel, some or all of those channels might support and/or require different security mechanisms. In such cases, an administrator could expose the simultaneous support for these multiple communication channels as multiple URIs for a single Printer object where each URI represents one of the communication channels to the Printer object. To support this flexibility, the IPP Printer object type defines a multi-valued identification attribute called the "printer-uri-supported" attribute. It MUST contain at least one URI. It MAY contain more than one URI. That is, every Printer object will have at least one URI that identifies at least one communication channel to the Printer object, but it may have more than one URI where each URI identifies a different communication channel to the Printer object. The "printer-uri-supported" attribute has two companion attributes, the "uri-security-supported" attribute and the "uri-authentication- supported". Both have the same cardinality as "printer-uri- supported". The purpose of the "uri-security-supported" attribute is to indicate the security mechanisms (if any) used for each URI listed in "printer-uri-supported". The purpose of the "uri-authentication- supported" attribute is to indicate the authentication mechanisms (if any) used for each URI listed in "printer-uri-supported". These three attributes are fully described in sections 4.4.1, 4.4.2, and 4.4.3.

When a job is submitted to the Printer object via a create request, the client supplies only a single Printer object URI. The client supplied Printer object URI MUST be one of the values in the "printer-uri-supported" Printer attribute.

IPP/1.1 does not specify how the client obtains the client supplied URI, but it is RECOMMENDED that a Printer object be registered as an entry in a directory service. End-users and programs can then interrogate the directory searching for Printers. Section 16 defines a generic schema for Printer object entries in the directory service and describes how the entry acts as a bridge to the actual IPP Printer object. The entry in the directory that represents the IPP Printer object includes the possibly many URIs for that Printer object as values in one its attributes.

When a client submits a create request to the Printer object, the Printer object validates the request and creates a new Job object. The Printer object assigns the new Job object a URI which is stored in the "job-uri" Job attribute. This URI is then used by clients as the target for subsequent Job operations. The Printer object generates a Job URI based on its configured security policy and the URI used by the client in the create request.

For example, consider a Printer object that supports both a communication channel secured by the use of SSL3 (using HTTP over SSL3 with an "https" schemed URI) and another open communication channel that is not secured with SSL3 (using a simple "http" schemed URI). If a client were to submit a job using the secure URI, the Printer object would assign the new Job object a secure URI as well. If a client were to submit a job using the open-channel URI, the Printer would assign the new Job object an open-channel URI.

In addition, the Printer object also populates the Job object's "job-printer-uri" attribute. This is a reference back to the Printer object that created the Job object. If a client only has access to a Job object's "job-uri" identifier, the client can query the Job's "job-printer-uri" attribute in order to determine which Printer object created the Job object. If the Printer object supports more than one URI, the Printer object picks the one URI supplied by the client when creating the job to build the value for and to populate the Job's "job-printer-uri" attribute.

Allowing Job objects to have URIs allows for flexibility and scalability. For example, in some implementations, the Printer object might create Jobs that are processed in the same local environment as the Printer object itself. In this case, the Job URI might just be a composition of the Printer's URI and some unique component for the Job object, such as the unique 32-bit positive integer mentioned later in this paragraph. In other implementations, the Printer object might be a central clearing-house for validating all Job object creation requests, but the Job object itself might be created in some environment that is remote from the Printer object. In this case, the Job object's URI may have no physical-location relationship at all to the Printer object's URI. Again, the fact that Job objects have URIs allows for flexibility and scalability, however, many existing printing systems have local models or interface constraints that force print jobs to be identified using only a 32-bit positive integer rather than an independent URI. This numeric Job ID is only unique within the context of the Printer object to which the create request was originally submitted. Therefore, in order to allow both types of client access to IPP Job objects (either by Job URI or by numeric Job ID), when the Printer object successfully processes a create request and creates a new Job object, the Printer object MUST generate both a Job URI and a Job ID. The Job ID (stored in the "job-id" attribute) only has meaning in the context of the Printer object to which the create request was originally submitted. This requirement to support both Job URIs and Job IDs allows all types of clients to access Printer objects and Job objects no matter the local constraints imposed on the client implementation.

In addition to identifiers, Printer objects and Job objects have names ("printer-name" and "job-name"). An object name NEED NOT be unique across all instances of all objects. A Printer object's name is chosen and set by an administrator through some mechanism outside the scope of this IPP/1.1 document. A Job object's name is optionally chosen and supplied by the IPP client submitting the job. If the client does not supply a Job object name, the Printer object generates a name for the new Job object. In all cases, the name only has local meaning.

To summarize:

      - Each Printer object is identified with one or more URIs.  The
        Printer's "printer-uri-supported" attribute contains the URI(s).
      - The Printer object's "uri-security-supported" attribute
        identifies the communication channel security protocols that may
        or may not have been configured for the various Printer object
        URIs (e.g., 'tls' or 'none').
      - The Printer object's "uri-authentication-supported" attribute
        identifies the authentication mechanisms that may or may not
        have been configured for the various Printer object URIs (e.g.,
        'digest' or 'none').
      - Each Job object is identified with a Job URI.  The Job's "job-
        uri" attribute contains the URI.
      - Each Job object is also identified with Job ID which is a 32-
        bit, positive integer.  The Job's "job-id" attribute contains
        the Job ID.  The Job ID is only unique within the context of the
        Printer object  which created the Job object.
      - Each Job object has a "job-printer-uri" attribute which contains
        the URI of the Printer object that was used to create the Job
        object.  This attribute is used to determine the Printer object
        that created a Job object when given only the URI for the Job
        object.  This linkage is necessary to determine the languages,
        charsets, and operations which are supported on that Job (the
        basis for such support comes from the creating Printer object).
      - Each Printer object has a name (which is not necessarily
        unique).  The administrator chooses and sets this name through
        some mechanism outside the scope of this IPP/1.1 document.  The
        Printer object's "printer-name" attribute contains the name.
      - Each Job object has a name (which is not necessarily unique).
        The client optionally supplies this name in the create request.
        If the client does not supply this name, the Printer object
        generates a name for the Job object. The Job object's "job-name"
        attribute contains the name.

3. IPP Operations

IPP objects support operations. An operation consists of a request and a response. When a client communicates with an IPP object, the client issues an operation request to the URI for that object. Operation requests and responses have parameters that identify the operation. Operations also have attributes that affect the run-time characteristics of the operation (the intended target, localization information, etc.). These operation-specific attributes are called operation attributes (as compared to object attributes such as Printer object attributes or Job object attributes). Each request carries along with it any operation attributes, object attributes, and/or document data required to perform the operation. Each request requires a response from the object. Each response indicates success or failure of the operation with a status code as a response parameter. The response contains any operation attributes, object attributes, and/or status messages generated during the execution of the operation request.

This section describes the semantics of the IPP operations, both requests and responses, in terms of the parameters, attributes, and other data associated with each operation.

The IPP/1.1 Printer operations are:

     Print-Job (section 3.2.1)
     Print-URI (section 3.2.2)
     Validate-Job (section 3.2.3)
     Create-Job (section 3.2.4)
     Get-Printer-Attributes (section 3.2.5)
     Get-Jobs (section 3.2.6)
     Pause-Printer (section 3.3.5)
     Resume-Printer (section 3.3.6)
     Purge-Jobs (section 3.3.7)

The Job operations are:

     Send-Document (section 3.3.1)
     Send-URI (section 3.3.2)
     Cancel-Job (section 3.3.3)
     Get-Job-Attributes (section 3.3.4)
     Hold-Job (section 3.3.5)
     Release-Job (section 3.3.6)
     Restart-Job (section 3.3.7)

The Send-Document and Send-URI Job operations are used to add a new document to an existing multi-document Job object created using the Create-Job operation.

3.1 Common Semantics

All IPP operations require some common parameters and operation attributes. These common elements and their semantic characteristics are defined and described in more detail in the following sections.

3.1.1 Required Parameters

Every operation request contains the following REQUIRED parameters:

- a "version-number",
- an "operation-id",
- a "request-id", and
- the attributes that are REQUIRED for that type of request.

Every operation response contains the following REQUIRED parameters:

      - a "version-number",
      - a "status-code",
      - the "request-id" that was supplied in the corresponding request,
        and
      - the attributes that are REQUIRED for that type of response.

The "Encoding and Transport" document [RFC2910] defines special rules for the encoding of these parameters. All other operation elements are represented using the more generic encoding rules for attributes and groups of attributes.

3.1.2 Operation IDs and Request IDs

Each IPP operation request includes an identifying "operation-id" value. Valid values are defined in the "operations-supported" Printer attribute section (see section 4.4.15). The client specifies which operation is being requested by supplying the correct "operation-id" value.

In addition, every invocation of an operation is identified by a "request-id" value. For each request, the client chooses the "request-id" which MUST be an integer (possibly unique depending on client requirements) in the range from 1 to 2**31 - 1 (inclusive). This "request-id" allows clients to manage multiple outstanding requests. The receiving IPP object copies all 32-bits of the client- supplied "request-id" attribute into the response so that the client can match the response with the correct outstanding request, even if the "request-id" is out of range. If the request is terminated before the complete "request-id" is received, the IPP object rejects the request and returns a response with a "request-id" of 0.

Note: In some cases, the transport protocol underneath IPP might be a connection oriented protocol that would make it impossible for a client to receive responses in any order other than the order in which the corresponding requests were sent. In such cases, the "request-id" attribute would not be essential for correct protocol operation. However, in other mappings, the operation responses can come back in any order. In these cases, the "request-id" would be essential.

3.1.3 Attributes

Operation requests and responses are both composed of groups of attributes and/or document data. The attributes groups are:

Operation Attributes: These attributes are passed in the operation and affect the IPP object's behavior while processing the operation request and may affect other attributes or groups of attributes. Some operation attributes describe the document data associated with the print job and are associated with new Job objects, however most operation attributes do not persist beyond the life of the operation. The description of each operation attribute includes conformance statements indicating which operation attributes are REQUIRED and which are OPTIONAL

        for an IPP object to support and which attributes a client MUST
        supply in a request and an IPP object MUST supply in a response.
      - Job Template Attributes: These attributes affect the processing
        of a job.  A client OPTIONALLY supplies Job Template Attributes
        in a create request, and the receiving object MUST be prepared
        to receive all supported attributes.  The Job object can later
        be queried to find out what Job Template attributes were
        originally requested in the create request, and such attributes
        are returned in the response as Job Object Attributes.  The
        Printer object can be queried about its Job Template attributes
        to find out what type of job processing capabilities are
        supported and/or what the default job processing behaviors are,
        though such attributes are returned in the response as Printer
        Object Attributes.  The "ipp-attribute-fidelity" operation
        attribute affects processing of all client-supplied Job Template
        attributes (see sections 3.2.1.2 and 15 for a full description
        of "ipp-attribute-fidelity" and its relationship to other
        attributes).
      - Job Object Attributes: These attributes are returned in response
        to a query operation directed at a Job object.
      - Printer Object Attributes: These attributes are returned in
        response to a query operation directed at a Printer object.
      - Unsupported Attributes: In a create request, the client supplies
        a set of Operation and Job Template attributes.  If any of these
        attributes or their values is unsupported by the Printer object,
        the Printer object returns the set of unsupported attributes in
        the response.  Sections 3.1.7, 3.2.1.2, and  15 give a full
        description of how Job Template attributes supplied by the
        client in a create request are processed by the Printer object
        and how unsupported attributes are returned to the client.
        Because of extensibility, any IPP object might receive a request
        that contains new or unknown attributes or values for which it
        has no support. In such cases, the IPP object processes what it
        can and returns the unsupported attributes in the response. The
        Unsupported Attribute group is defined for all operation
        responses for returning unsupported attributes that the client
        supplied in the request.

Later in this section, each operation is formally defined by identifying the allowed and expected groups of attributes for each request and response. The model identifies a specific order for each group in each request or response, but the attributes within each group may be in any order, unless specified otherwise.

The attributes within a group MUST be unique; if an attribute with the same name occurs more than once, the group is mal-formed. Clients MUST NOT submit such malformed requests and Printers MUST NOT return such malformed responses. If such a malformed request is submitted to a Printer, the Printer MUST either (1) reject the request with the 'client-error-bad-request' status code (see section 13.1.4.1) or (2) process the request normally after selecting only one of the attribute instances, depending on implementation. Which attribute is selected when there are duplicate attributes depends on implementation. The IPP Printer MUST NOT use the values from more than one such duplicate attribute instance.

Each attribute definition includes the attribute's name followed by the name of its attribute syntax(es) in parenthesizes. In addition, each 'integer' attribute is followed by the allowed range in parentheses, (m:n), for values of that attribute. Each 'text' or 'name' attribute is followed by the maximum size in octets in parentheses, (size), for values of that attribute. For more details on attribute syntax notation, see the descriptions of these attributes syntaxes in section 4.1.

Note: Document data included in the operation is not strictly an attribute, but it is treated as a special attribute group for ordering purposes. The only operations that support supplying the document data within an operation request are Print-Job and Send- Document. There are no operation responses that include document data.

Some operations are REQUIRED for IPP objects to support; the others are OPTIONAL (see section 5.2.2). Therefore, before using an OPTIONAL operation, a client SHOULD first use the REQUIRED Get- Printer-Attributes operation to query the Printer's "operations- supported" attribute in order to determine which OPTIONAL Printer and Job operations are actually supported. The client SHOULD NOT use an OPTIONAL operation that is not supported. When an IPP object receives a request to perform an operation it does not support, it returns the 'server-error-operation-not-supported' status code (see section 13.1.5.2). An IPP object is non-conformant if it does not support a REQUIRED operation.

3.1.4 Character Set and Natural Language Operation Attributes

Some Job and Printer attributes have values that are text strings and names intended for human understanding rather than machine understanding (see the 'text' and 'name' attribute syntax descriptions in section 4.1). The following sections describe two special Operation Attributes called "attributes-charset" and "attributes-natural-language". These attributes are always part of the Operation Attributes group. For most attribute groups, the order of the attributes within the group is not important. However, for these two attributes within the Operation Attributes group, the order is critical. The "attributes-charset" attribute MUST be the first attribute in the group and the "attributes-natural-language" attribute MUST be the second attribute in the group. In other words, these attributes MUST be supplied in every IPP request and response, they MUST come first in the group, and MUST come in the specified order. For job creation operations, the IPP Printer implementation saves these two attributes with the new Job object as Job Description attributes. For the sake of brevity in this document, these operation attribute descriptions are not repeated with every operation request and response, but have a reference back to this section instead.

3.1.4.1 Request Operation Attributes

The client MUST supply and the Printer object MUST support the following REQUIRED operation attributes in every IPP/1.1 operation request:

"attributes-charset" (charset):

This operation attribute identifies the charset (coded character set and encoding method) used by any 'text' and 'name' attributes that the client is supplying in this request. It also identifies the charset that the Printer object MUST use (if supported) for all 'text' and 'name' attributes and status messages that the Printer object returns in the response to this request. See Sections 4.1.1 and 4.1.2 for the definition of the 'text' and 'name' attribute syntaxes.

All clients and IPP objects MUST support the 'utf-8' charset [RFC2279] and MAY support additional charsets provided that they are registered with IANA [IANA-CS]. If the Printer object does not support the client supplied charset value, the Printer object MUST reject the request, set the "attributes-charset" to 'utf-8' in the response, and return the 'client-error-charset- not-supported' status code and any 'text' or 'name' attributes using the 'utf-8' charset. The Printer NEED NOT return any attributes in the Unsupported Attributes Group (See sections 3.1.7 and 3.2.1.2). The Printer object MUST indicate the charset(s) supported as the values of the "charset-supported" Printer attribute (see Section 4.4.18), so that the client can query to determine which charset(s) are supported.

Note to client implementers: Since IPP objects are only required to support the 'utf-8' charset, in order to maximize interoperability with multiple IPP object implementations, a client may want to supply 'utf-8' in the "attributes-charset" operation attribute, even though the client is only passing and able to present a simpler charset, such as US-ASCII [ASCII] or ISO-8859-1 [ISO8859-1]. Then the client will have to filter out (or charset convert) those characters that are returned in the response that it cannot present to its user. On the other hand, if both the client and the IPP objects also support a charset in common besides utf-8, the client may want to use that charset in order to avoid charset conversion or data loss.

See the 'charset' attribute syntax description in Section 4.1.7 for the syntax and semantic interpretation of the values of this attribute and for example values.

"attributes-natural-language" (naturalLanguage):

This operation attribute identifies the natural language used by any 'text' and 'name' attributes that the client is supplying in this request. This attribute also identifies the natural language that the Printer object SHOULD use for all 'text' and 'name' attributes and status messages that the Printer object returns in the response to this request. See the 'naturalLanguage' attribute syntax description in section 4.1.8 for the syntax and semantic interpretation of the values of this attribute and for example values.

There are no REQUIRED natural languages required for the Printer object to support. However, the Printer object's "generated-natural-language-supported" attribute identifies the natural languages supported by the Printer object and any contained Job objects for all text strings generated by the IPP object. A client MAY query this attribute to determine which natural language(s) are supported for generated messages.

For any of the attributes for which the Printer object generates text, i.e., for the "job-state-message", "printer- state-message", and status messages (see Section 3.1.6), the Printer object MUST be able to generate these text strings in any of its supported natural languages. If the client requests a natural language that is not supported, the Printer object MUST return these generated messages in the Printer's configured natural language as specified by the Printer's "natural-language-configured" attribute" (see Section 4.4.19).

For other 'text' and 'name' attributes supplied by the client, authentication system, operator, system administrator, or manufacturer (i.e., for "job-originating-user-name", "printer- name" (name), "printer-location" (text), "printer-info" (text), and "printer-make-and-model" (text)), the Printer object is only required to support the configured natural language of the

Printer identified by the Printer object's "natural-language-

configured" attribute, though support of additional natural

languages for these attributes is permitted.

For any 'text' or 'name' attribute in the request that is in a different natural language than the value supplied in the "attributes-natural-language" operation attribute, the client MUST use the Natural Language Override mechanism (see sections 4.1.1.2 and 4.1.2.2) for each such attribute value supplied. The client MAY use the Natural Language Override mechanism redundantly, i.e., use it even when the value is in the same natural language as the value supplied in the "attributes- natural-language" operation attribute of the request.

The IPP object MUST accept any natural language and any Natural Language Override, whether the IPP object supports that natural language or not (and independent of the value of the "ipp- attribute-fidelity" Operation attribute). That is the IPP object accepts all client supplied values no matter what the values are in the Printer object's "generated-natural- language-supported" attribute. That attribute, "generated- natural-language-supported", only applies to generated messages, not client supplied messages. The IPP object MUST remember that natural language for all client-supplied attributes, and when returning those attributes in response to a query, the IPP object MUST indicate that natural language.

Each value whose attribute syntax type is 'text' or 'name' (see sections 4.1.1 and 4.1.2) has an Associated Natural-Language. This document does not specify how this association is stored in a Printer or Job object. When such a value is encoded in a request or response, the natural language is either implicit or explicit:

In the implicit case, the value contains only the text/name value, and the language is specified by the "attributes- natural-language" operation attribute in the request or response (see sections 4.1.1.1 textWithoutLanguage and 4.1.2.1 nameWithoutLanguage).

In the explicit case (also known as the Natural-Language Override case), the value contains both the language and the text/name value (see sections 4.1.1.2 textWithLanguage and 4.1.2.2 nameWithLanguage).

For example, the "job-name" attribute MAY be supplied by the

client in a create request. The text value for this attribute

will be in the natural language identified by the "attribute-

         natural-language" attribute, or if different, as identified by
         the Natural Language Override mechanism.  If supplied, the IPP
         object will use the value of the "job-name" attribute to
         populate the Job object's "job-name" attribute.  Whenever any
         client queries the Job object's "job-name" attribute, the IPP
         object returns the attribute as stored and uses the Natural
         Language Override mechanism to specify the natural language, if
         it is different from that reported in the "attributes-natural-
         language" operation attribute of the response.  The IPP object
         MAY use the Natural Language Override mechanism redundantly,
         i.e., use it even when the value is in the same natural
         language as the value supplied in the "attributes-natural-
         language" operation attribute of the response.

An IPP object MUST NOT reject a request based on a supplied natural language in an "attributes-natural-language" Operation attribute or in any attribute that uses the Natural Language Override.

Clients SHOULD NOT supply 'text' or 'name' attributes that use an illegal combination of natural language and charset. For example, suppose a Printer object supports charsets 'utf-8', 'iso-8859-1', and 'iso-8859-7'. Suppose also, that it supports natural languages 'en' (English), 'fr' (French), and 'el' (Greek). Although the Printer object supports the charset 'iso-8859-1' and natural language 'el', it probably does not support the combination of Greek text strings using the 'iso-8859-1' charset. The Printer object handles this apparent incompatibility differently depending on the context in which it occurs:

      - In a create request: If the client supplies a text or name
        attribute (for example, the "job-name" operation attribute) that
        uses an apparently incompatible combination, it is a client
        choice that does not affect the Printer object or its correct
        operation.  Therefore, the Printer object simply accepts the
        client supplied value, stores it with the Job object, and
        responds back with the same combination whenever the client (or
        any client) queries for that attribute.
      - In a query-type operation, like Get-Printer-Attributes: If the
        client requests an apparently incompatible combination, the
        Printer object responds (as described in section 3.1.4.2) using
        the Printer's configured natural language rather than the
        natural language requested by the client.

In either case, the Printer object does not reject the request because of the apparent incompatibility. The potential incompatible combination of charset and natural language can occur either at the global operation level or at the Natural Language Override attribute-by-attribute level. In addition, since the response always includes explicit charset and natural language information, there is never any question or ambiguity in how the client interprets the response.

3.1.4.2 Response Operation Attributes

The Printer object MUST supply and the client MUST support the following REQUIRED operation attributes in every IPP/1.1 operation response:

"attributes-charset" (charset):

This operation attribute identifies the charset used by any 'text' and 'name' attributes that the Printer object is returning in this response. The value in this response MUST be the same value as the "attributes-charset" operation attribute supplied by the client in the request. If this is not possible (i.e., the charset requested is not supported), the request would have been rejected. See "attributes-charset" described in Section 3.1.4.1 above.

If the Printer object supports more than just the 'utf-8' charset, the Printer object MUST be able to code convert between each of the charsets supported on a highest fidelity possible basis in order to return the 'text' and 'name' attributes in the charset requested by the client. However, some information loss MAY occur during the charset conversion depending on the charsets involved. For example, the Printer object may convert from a UTF-8 'a' to a US-ASCII 'a' (with no loss of information), from an ISO Latin 1 CAPITAL LETTER A WITH ACUTE ACCENT to US-ASCII 'A' (losing the accent), or from a UTF-8 Japanese Kanji character to some ISO Latin 1 error character indication such as '?', decimal code equivalent, or to the absence of a character, depending on implementation.

Whether an implementation that supports more than one charset stores the data in the charset supplied by the client or code converts to one of the other supported charsets, depends on implementation. The strategy should try to minimize loss of information during code conversion. On each response, such an implementation converts from its internal charset to that requested.

"attributes-natural-language" (naturalLanguage):: This operation attribute identifies the natural language used by any 'text' and 'name' attributes that the IPP object is returning in this response. Unlike the "attributes-charset" operation attribute, the IPP object NEED NOT return the same value as that supplied by the client in the request. The IPP object MAY return the natural language of the Job object or the Printer's configured natural language as identified by the Printer object's "natural-language-configured" attribute, rather than the natural language supplied by the client. For any 'text' or 'name' attribute or status message in the response that is in a different natural language than the value returned in the "attributes-natural-language" operation attribute, the IPP object MUST use the Natural Language Override mechanism (see sections 4.1.1.2 and 4.1.2.2) on each attribute value returned. The IPP object MAY use the Natural Language Override mechanism redundantly, i.e., use it even when the value is in the same natural language as the value supplied in the "attributes-natural-language" operation attribute of the response.

3.1.5 Operation Targets

All IPP operations are directed at IPP objects. For Printer operations, the operation is always directed at a Printer object using one of its URIs (i.e., one of the values in the Printer object's "printer-uri-supported" attribute). Even if the Printer object supports more than one URI, the client supplies only one URI as the target of the operation. The client identifies the target object by supplying the correct URI in the "printer-uri (uri)" operation attribute.

For Job operations, the operation is directed at either:

      - The Job object itself using the Job object's URI.  In this case,
        the client identifies the target object by supplying the correct
        URI in the "job-uri (uri)" operation attribute.
      - The Printer object that created the Job object using both the
        Printer objects URI and the Job object's Job ID.  Since the
        Printer object that created the Job object generated the Job ID,
        it MUST be able to correctly associate the client supplied Job
        ID with the correct Job object.  The client supplies the Printer
        object's URI in the "printer-uri (uri)" operation attribute and
        the Job object's Job ID in the "job-id (integer(1:MAX))"
        operation attribute.

If the operation is directed at the Job object directly using the Job object's URI, the client MUST NOT include the redundant "job-id" operation attribute.

The operation target attributes are REQUIRED operation attributes that MUST be included in every operation request. Like the charset and natural language attributes (see section 3.1.4), the operation target attributes are specially ordered operation attributes. In all cases, the operation target attributes immediately follow the "attributes-charset" and "attributes-natural-language" attributes within the operation attribute group, however the specific ordering rules are:

      - In the case where there is only one operation target attribute
        (i.e., either only the "printer-uri" attribute or only the
        "job-uri" attribute), that attribute MUST be the third attribute
        in the operation attributes group.
      - In the case where Job operations use two operation target
        attributes (i.e., the "printer-uri" and "job-id" attributes),
        the "printer-uri" attribute MUST be the third attribute and the
        "job-id" attribute MUST be the fourth attribute.

In all cases, the target URIs contained within the body of IPP operation requests and responses must be in absolute format rather than relative format (a relative URL identifies a resource with the scope of the HTTP server, but does not include scheme, host or port).

The following rules apply to the use of port numbers in URIs that identify IPP objects:

If the URI scheme allows the port number to be explicitly included in the URI string, and a port number is specified within the URI, then that port number MUST be used by the client to contact the IPP object.

If the URI scheme allows the port number to be explicitly included in the URI string, and a port number is not specified within the URI, then default port number implied by that URI scheme MUST be used by the client to contact the IPP object.

If the URI scheme does not allow an explicit port number to be specified within the URI, then the default port number implied by that URI MUST be used by the client to contact the IPP object.

Note: The IPP "Encoding and Transport document [RFC2910] shows a mapping of IPP onto HTTP/1.1 [RFC2616] and defines a new default port number for using IPP over HTTP/1.1.

3.1.6 Operation Response Status Codes and Status Messages

Every operation response includes a REQUIRED "status-code" parameter and an OPTIONAL "status-message" operation attribute, and an OPTIONAL "detailed-status-message" operation attribute. The Print-URI and Send-URI response MAY include an OPTIONAL "document-access-error" operation attribute.

3.1.6.1 "status-code" (type2 enum)

The REQUIRED "status-code" parameter provides information on the processing of a request.

The status code is intended for use by automata. A client implementation of IPP SHOULD convert status code values into any localized message that has semantic meaning to the end user.

The "status-code" value is a numeric value that has semantic meaning. The "status-code" syntax is similar to a "type2 enum" (see section 4.1 on "Attribute Syntaxes") except that values can range only from 0x0000 to 0x7FFF. Section 13 describes the status codes, assigns the numeric values, and suggests a corresponding status message for each status code for use by the client when the user's natural language is English.

If the Printer performs an operation with no errors and it encounters no problems, it MUST return the status code 'successful-ok' in the response. See section 13.

If the client supplies unsupported values for the following parameters or Operation attributes, the Printer object MUST reject the operation, NEED NOT return the unsupported attribute value in the Unsupported Attributes group, and MUST return the indicated status code:

        Parameter/Attribute                 Status code
        
        version-number      server-error-version-not-supported
        operation-id        server-error-operation-not-supported
        attributes-charset  client-error-charset-not-supported
        compression         client-error-compression-not-supported
        document-format     client-error-document-format-not-supported
        document-uri        client-error-uri-scheme-not-supported,
                             client-error-document-access-error

If the client supplies unsupported values for other attributes, or unsupported attributes, the Printer returns the status code defined in section 3.1.7 on Unsupported Attributes.

3.1.6.2 "status-message" (text(255))

The OPTIONAL "status-message" operation attribute provides a short textual description of the status of the operation. The "status- message" attribute's syntax is "text(255)", so the maximum length is 255 octets (see section 4.1.1). The status message is intended for the human end user. If a response does include a "status-message" attribute, an IPP client NEED NOT examine or display the messages, however it SHOULD do so in some implementation specific manner. The "status-message" is especially useful for a later version of a Printer object to return as supplemental information for the human user to accompany a status code that an earlier version of a client might not understand.

If the Printer object supports the "status-message" operation attribute, the Printer object MUST be able to generate this message in any of the natural languages identified by the Printer object's "generated-natural-language-supported" attribute (see the "attributes-natural-language" operation attribute specified in section 3.1.4.1. Section 13 suggests the text for the status message returned by the Printer for use with the English natural language.

As described in section 3.1.4.1 for any returned 'text' attribute, if there is a choice for generating this message, the Printer object uses the natural language indicated by the value of the "attributes- natural-language" in the client request if supported, otherwise the Printer object uses the value in the Printer object's own "natural- language-configured" attribute.

   If the Printer object supports the "status-message" operation
   attribute, it SHOULD use the REQUIRED 'utf-8' charset to return a
   status message for the following error status codes (see section 13):
   'client-error-bad-request', 'client-error-charset-not-supported',
   'server-error-internal-error', 'server-error-operation-not-
   supported', and 'server-error-version-not-supported'.  In this case,
   it MUST set the value of the "attributes-charset" operation attribute
   to 'utf-8' in the error response.

3.1.6.3 "detailed-status-message" (text(MAX))

   The OPTIONAL "detailed-status-message" operation attribute provides
   additional more detailed technical and implementation-specific
   information about the operation.  The "detailed-status-message"
   attribute's syntax is "text(MAX)", so the maximum length is 1023
   octets (see section 4.1.1).    If the Printer objects supports the
   "detailed-status-message" operation attribute, the Printer NEED NOT
   localize the message, since it is intended for use by the system
   administrator or other experienced technical persons.  Localization

might obscure the technical meaning of such messages. Clients MUST NOT attempt to parse the value of this attribute. See the "document-access-error" operation attribute (section 3.1.6.4) for additional errors that a program can process.

3.1.6.4 "document-access-error" (text(MAX))

This OPTIONAL operation attribute provides additional information about any document access errors encountered by the Printer before it returned a response to the Print-URI (section 3.2.2) or Send-URI (section 3.3.1) operation. For errors in the protocol identified by the URI scheme in the "document-uri" operation attribute, such as 'http:' or 'ftp:', the error code is returned in parentheses, followed by the URI. For example:

      (404) http://ftp.pwg.org/pub/pwg/ipp/new_MOD/ipp-model-v11.pdf

Most Internet protocols use decimal error codes (unlike IPP), so the ASCII error code representation is in decimal.

3.1.7 Unsupported Attributes

The Unsupported Attributes group contains attributes that are not supported by the operation. This group is primarily for the job creation operations, but all operations can return this group.

   A Printer object MUST include an Unsupported Attributes group in a
   response if the status code is one of the following:  'successful-
   ok-ignored-or-substituted-attributes', 'successful-ok-conflicting-
   attributes', 'client-error-attributes-or-values-not-supported' or
   'client-error-conflicting-attributes'.

If the status code is one of the four specified in the preceding paragraph, the Unsupported Attributes group MUST contain all of those attributes and only those attributes that are:

a. an Operation or Job Template attribute supplied in the request,

and

b. unsupported by the printer. See below for details on the three: categories "unsupported" attributes.

If the status code is one of those in the table in section 3.1.6.1, the Unsupported Attributes group NEED NOT contain the unsupported parameter or attribute indicated in that table.

If the Printer object is not returning any Unsupported Attributes in the response, the Printer object SHOULD omit Group 2 rather than sending an empty group. However, a client MUST be able to accept an empty group.

Unsupported attributes fall into three categories:

The Printer object does not support the supplied attribute (no matter what the attribute syntax or value).

The Printer object does support the attribute, but does not support some or all of the particular attribute syntaxes or values supplied by the client (i.e., the Printer object does not have those attribute syntaxes or values in its corresponding "xxx-supported" attribute).

The Printer object does support the attributes and values supplied, but the particular values are in conflict with one another, because they violate a constraint, such as not being able to staple transparencies.

   In the case of an unsupported attribute name, the Printer object
   returns the client-supplied attribute with a substituted value of
   'unsupported'.  This value's syntax type is "out-of-band" and its
   encoding is defined by special rules for "out-of-band" values in the
   "Encoding and Transport" document [RFC2910].   Its value indicates no
   support for the attribute itself (see the beginning of section 4.1).

In the case of a supported attribute with one or more unsupported attribute syntaxes or values, the Printer object simply returns the client-supplied attribute with the unsupported attribute syntaxes or values as supplied by the client. This indicates support for the attribute, but no support for that particular attribute syntax or value. If the client supplies a multi-valued attribute with more than one value and the Printer object supports the attribute but only supports a subset of the client-supplied attribute syntaxes or values, the Printer object

MUST return only those attribute syntaxes or values that are unsupported.

In the case of two (or more) supported attribute values that are in conflict with one another (although each is supported independently, the values conflict when requested together within the same job), the Printer object MUST return all the values that it ignores or substitutes to resolve the conflict, but not any of the values that it is still using. The choice for exactly how to resolve the conflict is implementation dependent. See sections 3.2.1.2 and 15. See The Implementer's Guide [IPP-IIG] for an example.

3.1.8 Versions

   Each operation request and response carries with it a "version-
   number" parameter.  Each value of the "version-number" is in the form
   "X.Y" where X is the major version number and Y is the minor version
   number.  By including a version number in the client request, it
   allows the client  to identify which version of IPP it is interested
   in using, i.e., the version whose conformance requirements the client
   may be depending upon the Printer to meet.

If the IPP object does not support that major version number supplied by the client, i.e., the major version field of the "version-number" parameter does not match any of the values of the Printer's "ipp- versions-supported" (see section 4.4.14), the object MUST respond with a status code of 'server-error-version-not-supported' along with the closest version number that is supported (see section 13.1.5.4). If the major version number is supported, but the minor version number is not, the IPP object SHOULD accept and attempt to perform the request (or reject the request if the operation is not supported), else it rejects the request and returns the 'server- error-version-not-supported' status code. In all cases, the IPP object MUST return the "version-number" that it supports that is closest to the version number supplied by the client in the request.

There is no version negotiation per se. However, if after receiving a 'server-error-version-not-supported' status code from an IPP object, a client SHOULD try again with a different version number. A client MAY also determine the versions supported either from a directory that conforms to Appendix E (see section 16) or by querying the Printer object's "ipp-versions-supported" attribute (see section 4.4.14) to determine which versions are supported.

An IPP object implementation MUST support version '1.1', i.e., meet the conformance requirements for IPP/1.1 as specified in this document and [RFC2910]. It is recommended that IPP object implementations accept any request with the major version '1' (or reject the request if the operation is not supported).

There is only one notion of "version number" that covers both IPP Model and IPP Protocol changes. Thus the version number MUST change when introducing a new version of the Model and Semantics document (this document) or a new version of the "Encoding and Transport" document [RFC2910].

Changes to the major version number of the Model and Semantics document indicate structural or syntactic changes that make it impossible for older version of IPP clients and Printer objects to correctly parse and correctly process the new or changed attributes, operations and responses. If the major version number changes, the minor version numbers is set to zero. As an example, adding the REQUIRED "ipp-attribute-fidelity" attribute to version '1.1' (if it had not been part of version '1.0'), would have required a change to the major version number, since an IPP/1.0 Printer would not have processed a request with the correct semantics that contained the "ipp-attribute-fidelity" attribute that it did not know about. Items that might affect the changing of the major version number include any changes to the Model and Semantics document (this document) or the "Encoding and Transport" document [RFC2910] itself, such as:

      - reordering of ordered attributes or attribute sets
      - changes to the syntax of existing attributes
      - adding REQUIRED (for an IPP object to support) operation
        attribute groups
      - adding values to existing REQUIRED operation attributes
      - adding REQUIRED operations

Changes to the minor version number indicate the addition of new features, attributes and attribute values that may not be understood by all IPP objects, but which can be ignored if not understood. Items that might affect the changing of the minor version number include any changes to the model objects and attributes but not the encoding and transport rules [RFC2910] (except adding attribute syntaxes). Examples of such changes are:

      - grouping all extensions not included in a previous version into
        a new version
      - adding new attribute values
      - adding new object attributes
      - adding OPTIONAL (for an IPP object to support) operation
        attributes (i.e., those attributes that an IPP object can ignore
        without confusing clients)
      - adding OPTIONAL (for an IPP object to support) operation
        attribute groups (i.e., those attributes that an IPP object can
        ignore without confusing clients)
      - adding new attribute syntaxes
      - adding OPTIONAL operations
      - changing Job Description attributes or Printer Description
        attributes from OPTIONAL to REQUIRED or vice versa.
      - adding OPTIONAL attribute syntaxes to an existing attribute.

The encoding of the "version-number" MUST NOT change over any version number (either major or minor). This rule guarantees that all future

   versions will be backwards compatible with all previous versions (at
   least for checking  the "version-number").  In addition, any protocol
   elements (attributes, error codes, tags, etc.) that are not carried
   forward from one version to the next are deprecated so that they can
   never be reused with new semantics.
   
   Implementations that support a certain  version NEED NOT support ALL
   previous versions.  As each new  version is defined (through the
   release of a new IPP specification document), that version will
   specify which previous  versions MUST and which versions SHOULD be
   supported in compliant implementations.

3.1.9 Job Creation Operations

In order to "submit a print job" and create a new Job object, a client issues a create request. A create request is any one of following three operation requests:

The Print-Job Request: A client that wants to submit a print job with only a single document uses the Print-Job operation. The operation allows for the client to "push" the document data to the Printer object by including the document data in the request itself.

The Print-URI Request: A client that wants to submit a print job with only a single document (where the Printer object "pulls" the document data instead of the client "pushing" the data to the Printer object) uses the Print-URI operation. In this case, the client includes in the request only a URI reference to the document data (not the document data itself).

The Create-Job Request: A client that wants to submit a print job with multiple documents uses the Create-Job operation. This operation is followed by an arbitrary number (one or more) of Send-Document and/or Send-URI operations (each creating another document for the newly create Job object). The Send-Document operation includes the document data in the request (the client "pushes" the document data to the printer), and the Send-URI operation includes only a URI reference to the document data in the request (the Printer "pulls" the document data from the referenced location). The last Send-Document or Send-URI request for a given Job object includes a "last-document" operation attribute set to 'true' indicating that this is the last request.

Throughout this model document, the term "create request" is used to refer to any of these three operation requests.

A Create-Job operation followed by only one Send-Document operation is semantically equivalent to a Print-Job operation, however, for performance reasons, the client SHOULD use the Print-Job operation for all single document jobs. Also, Print-Job is a REQUIRED operation (all implementations MUST support it) whereas Create-Job is an OPTIONAL operation, hence some implementations might not support it.

Job submission time is the point in time when a client issues a create request. The initial state of every Job object is the 'pending', 'pending-held', or 'processing' state (see section 4.3.7). When the Printer object begins processing the print job, the Job object's state moves to 'processing'. This is known as job processing time. There are validation checks that must be done at job submission time and others that must be performed at job processing time.

At job submission time and at the time a Validate-Job operation is received, the Printer MUST do the following:

      1. Process the client supplied attributes and either accept or
         reject the request
      2. Validate the syntax of and support for the scheme of any client
         supplied URI

At job submission time the Printer object MUST validate whether or not the supplied attributes, attribute syntaxes, and values are supported by matching them with the Printer object's corresponding "xxx-supported" attributes. See section 3.1.7 for details. [IPP- IIG] presents suggested steps for an IPP object to either accept or reject any request and additional steps for processing create requests.

At job submission time the Printer object NEED NOT perform the validation checks reserved for job processing time such as:

1. Validating the document data
2. Validating the actual contents of any client supplied URI

(resolve the reference and follow the link to the document data)

At job submission time, these additional job processing time validation checks are essentially useless, since they require actually parsing and interpreting the document data, are not guaranteed to be 100% accurate, and MUST be done, yet again, at job processing time. Also, in the case of a URI, checking for availability at job submission time does not guarantee availability at job processing time. In addition, at job processing time, the Printer object might discover any of the following conditions that were not detectable at job submission time:

      - runtime errors in the document data,
      - nested document data that is in an unsupported format,
      - the URI reference is no longer valid (i.e., the server hosting
        the document might be down), or
      - any other job processing error

At job submission time, a Printer object, especially a non-spooling Printer, MAY accept jobs that it does not have enough space for. In such a situation, a Printer object MAY stop reading data from a client for an indefinite period of time. A client MUST be prepared for a write operation to block for an indefinite period of time (see section 5.1 on client conformance).

When a Printer object has too little space for starting a new job, it MAY reject a new create request. In this case, a Printer object MUST return a response (in reply to the rejected request) with a status- code of 'server-error-busy' (see section 14.1.5.8) and it MAY close the connection before receiving all bytes of the operation. A Printer SHOULD indicate that it is temporarily unable to accept jobs by setting the 'spool-space-full' value in its "printer-state- reasons" attribute and removing the value when it can accept another job (see section 4.4.12).

When receiving a 'server-error-busy' status-code in an operation response, a client MUST be prepared for the Printer object to close the connection before the client has sent all of the data (especially for the Print-Job operation). A client MUST be prepared to keep submitting a create request until the IPP Printer object accepts the create request.

   At job processing time, since the Printer object has already
   responded with a successful status code in the response to the create
   request, if the Printer object detects an error, the Printer object
   is unable to inform the end user of the error with an operation
   status code.   In this case, the Printer, depending on the error, can
   set the job object's "job-state", "job-state-reasons", or "job-
   state-message" attributes to the appropriate value(s) so that later
   queries can report the correct job status.

Note: Asynchronous notification of events is outside the scope of this IPP/1.1 document.

3.2 Printer Operations

All Printer operations are directed at Printer objects. A client MUST always supply the "printer-uri" operation attribute in order to identify the correct target of the operation.

3.2.1 Print-Job Operation

This REQUIRED operation allows a client to submit a print job with only one document and supply the document data (rather than just a reference to the data). See Section 15 for the suggested steps for processing create operations and their Operation and Job Template attributes.

3.2.1.1 Print-Job Request

The following groups of attributes are supplied as part of the Print-Job Request:

Group 1: Operation Attributes

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1. The Printer object MUST copy these values to the corresponding Job Description attributes described in sections 4.3.19 and 4.3.20.

Target:: The "printer-uri" (uri) operation attribute which is the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

"job-name" (name(MAX)):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It contains the client supplied Job name. If this attribute is supplied by the client, its value is used for the "job-name" attribute of the newly created Job object. The client MAY automatically include any information that will help the end-user distinguish amongst his/her jobs, such as the name of the application program along with information from the document, such as the document name, document subject, or source file name. If this attribute is not supplied by the client, the Printer generates a name to use in the "job-name" attribute of the newly created Job object (see Section 4.3.5).

"ipp-attribute-fidelity" (boolean):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. The value 'true' indicates that total fidelity to client supplied Job Template attributes and values is required, else the Printer object MUST reject the Print-Job request. The value 'false' indicates that a reasonable attempt to print the Job object is acceptable and the Printer object MUST accept the Print-Job request. If not supplied, the Printer object assumes the value is 'false'. All Printer objects MUST support both types of job processing. See section 15 for a full description of "ipp-attribute-fidelity" and its relationship to other attributes, especially the Printer object's "pdl-override-supported" attribute.

"document-name" (name(MAX)):

         The client OPTIONALLY supplies this attribute.  The Printer
         object MUST support this attribute.   It contains the client
         supplied document name.  The document name MAY be different
         than the Job name.  Typically, the client software
         automatically supplies the document name on behalf of the end
         user by using a file name or an application generated name.  If
         this attribute is supplied, its value can be used in a manner
         defined by each implementation.  Examples include: printed
         along with the Job (job start sheet, page adornments, etc.),
         used by accounting or resource tracking management tools, or
         even stored along with the document as a document level
         attribute.  IPP/1.1 does not support the concept of document
         level attributes.

"compression" (type3 keyword):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute and the "compression- supported" attribute (see section 4.4.32). The client supplied "compression" operation attribute identifies the compression algorithm used on the document data. The following cases exist:

         a) If the client omits this attribute, the Printer object MUST
            assume that the data is not compressed   (i.e. the Printer
            follows the rules below as if the client supplied the
            "compression" attribute with a value of 'none').
         b) If the client supplies this attribute, but the value is not
            supported by the Printer object, i.e., the value is not one
            of the values of the Printer object's "compression-
            supported" attribute, the Printer object MUST reject the
            request, and return the 'client-error-compression-not-
            supported' status code. See section 3.1.7 for returning
            unsupported attributes and values.
         c) If the client supplies the attribute and the Printer object
            supports the attribute value, the Printer object uses the
            corresponding decompression algorithm on the document data.
         d) If the decompression algorithm fails before the Printer
            returns an operation response, the Printer object MUST
            reject the request and return the 'client-error-
            compression-error' status code.
         e) If the decompression algorithm fails after the Printer
            returns an operation response, the Printer object MUST abort
            the job and add the 'compression-error' value to the job's
            "job-state-reasons" attribute.
         f) If the decompression algorithm succeeds, the document data
            MUST then have the format specified by the job's "document-
            format" attribute, if supplied (see "document-format"
            operation attribute definition below).

"document-format" (mimeMediaType):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. The value of this attribute identifies the format of the supplied document data. The following cases exist:

         a) If the client does not supply this attribute, the Printer
            object assumes that the document data is in the format
            defined by the Printer object's "document-format-default"
            attribute. (i.e. the Printer follows the rules below as if
            the client supplied the "document-format" attribute with a
            value equal to the printer's default value).
         b) If the client supplies this attribute, but the value is not
            supported by the Printer object, i.e., the value is not one
            of the values of the Printer object's "document-format-
            supported" attribute, the Printer object MUST reject the
            request and return the 'client-error-document-format-not-
            supported' status code.
         c) If the client supplies this attribute and its value is
            'application/octet-stream' (i.e. to be auto-sensed, see
            Section 4.1.9.1), and the format is not one of the
            document-formats that the Printer can auto-sense, and this
            check occurs before the Printer returns an operation
            response, then the Printer MUST reject the request and
            return the  'client-error-document-format-not-supported'
            status code.
         d) If the client supplies this attribute, and the value is
            supported by the Printer object, the Printer is capable of
            interpreting the document data.
         e) If interpreting of the document data fails before the
            Printer returns an operation response, the Printer object
            MUST reject the request and return the 'client-error-
            document-format-error' status code.
         f) If interpreting of the document data fails after the Printer
            returns an operation response, the Printer object MUST abort
            the job and add the 'document-format-error' value to the
            job's "job-state-reasons" attribute.

"document-natural-language" (naturalLanguage):: The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute. This attribute specifies the natural language of the document for those document-formats that require a specification of the natural language in order to image the document unambiguously. There are no particular values required for the Printer object to support.

"job-k-octets" (integer(0:MAX)):

The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute and the "job-k- octets-supported" attribute (see section 4.4.33). The client supplied "job-k-octets" operation attribute identifies the total size of the document(s) in K octets being submitted (see section 4.3.17.1 for the complete semantics). If the client supplies the attribute and the Printer object supports the attribute, the value of the attribute is used to populate the Job object's "job-k-octets" Job Description attribute.

For this attribute and the following two attributes ("job- impressions", and "job-media-sheets"), if the client supplies the attribute, but the Printer object does not support the attribute, the Printer object ignores the client-supplied value. If the client supplies the attribute and the Printer supports the attribute, and the value is within the range of the corresponding Printer object's "xxx-supported" attribute, the Printer object MUST use the value to populate the Job object's "xxx" attribute. If the client supplies the attribute and the Printer supports the attribute, but the value is outside the range of the corresponding Printer object's "xxx- supported" attribute, the Printer object MUST copy the attribute and its value to the Unsupported Attributes response group, reject the request, and return the 'client-error- attributes-or-values-not-supported' status code. If the client does not supply the attribute, the Printer object MAY choose to populate the corresponding Job object attribute depending on whether the Printer object supports the attribute and is able to calculate or discern the correct value.

"job-impressions" (integer(0:MAX)):

The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute and the "job- impressions-supported" attribute (see section 4.4.34). The client supplied "job-impressions" operation attribute identifies the total size in number of impressions of the document(s) being submitted (see section 4.3.17.2 for the complete semantics).

See last paragraph under "job-k-octets".

"job-media-sheets" (integer(0:MAX)):

The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute and the "job-media- sheets-supported" attribute (see section 4.4.35). The client supplied "job-media-sheets" operation attribute identifies the total number of media sheets to be produced for this job (see section 4.3.17.3 for the complete semantics).

See last paragraph under "job-k-octets".

Group 2: Job Template Attributes

The client OPTIONALLY supplies a set of Job Template attributes as defined in section 4.2. If the client is not supplying any Job Template attributes in the request, the client SHOULD omit Group 2 rather than sending an empty group. However, a Printer object MUST be able to accept an empty group.

Group 3: Document Content

The client MUST supply the document data to be processed.

In addition to the MANDATORY parameters required for every operation request, the simplest Print-Job Request consists of just the "attributes-charset" and "attributes-natural-language" operation attributes; the "printer-uri" target operation attribute; the Document Content and nothing else. In this simple case, the Printer object:

      - creates a new Job object (the Job object contains a single
        document),
      - stores a generated Job name in the "job-name" attribute in the
        natural language and charset requested (see Section 3.1.4.1) (if
        those are supported, otherwise using the Printer object's
        default natural language and charset), and

at job processing time, uses its corresponding default value attributes for the supported Job Template attributes that were not supplied by the client as IPP attribute or embedded instructions in the document data.

3.2.1.2 Print-Job Response

The Printer object MUST return to the client the following sets of attributes as part of the Print-Job Response:

Group 1: Operation Attributes

Status Message:: In addition to the REQUIRED status code returned in every response, the response OPTIONALLY includes a "status-message" (text(255)) and/or a "detailed-status-message" (text(MAX)) operation attribute as described in sections 13 and 3.1.6. If the client supplies unsupported or conflicting Job Template attributes or values, the Printer object MUST reject or accept the Print-Job request depending on the whether the client supplied a 'true' or 'false' value for the "ipp-attribute- fidelity" operation attribute. See the Implementer's Guide [IPP-IIG] for a complete description of the suggested steps for processing a create request.

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

The value of the "ipp-attribute-fidelity" supplied by the client does not affect what attributes the Printer object returns in this group. The value of "ipp-attribute-fidelity" only affects whether the Print-Job operation is accepted or rejected. If the job is accepted, the client may query the job using the Get-Job- Attributes operation requesting the unsupported attributes that were returned in the create response to see which attributes were ignored (not stored on the Job object) and which attributes were stored with other (substituted) values.

Group 3: Job Object Attributes

"job-uri" (uri):: The Printer object MUST return the Job object's URI by returning the contents of the REQUIRED "job-uri" Job object attribute. The client uses the Job object's URI when directing operations at the Job object. The Printer object always uses its configured security policy when creating the new URI. However, if the Printer object supports more than one URI, the Printer object also uses information about which URI was used in the Print-Job Request to generated the new URI so that the new URI references the correct access channel. In other words, if the Print-Job Request comes in over a secure channel, the Printer object MUST generate a Job URI that uses the secure channel as well.

"job-id" (integer(1:MAX)):

         The Printer object MUST return the Job object's Job ID by
         returning the REQUIRED  "job-id" Job object attribute.  The
         client uses this "job-id" attribute in conjunction with the
         "printer-uri" attribute used in the Print-Job Request when
         directing Job operations at the Printer object.

"job-state" (type1 enum):

         The Printer object MUST return the Job object's REQUIRED "job-
         state" attribute. The value of this attribute (along with the
         value of the next attribute:  "job-state-reasons") is taken
         from a "snapshot" of the new Job object at some meaningful
         point in time (implementation defined) between when the Printer
         object receives the Print-Job Request and when the Printer
         object returns the response.

"job-state-reasons" (1setOf type2 keyword):: The Printer object MUST return the Job object's REQUIRED "job- state-reasons" attribute.

"job-state-message" (text(MAX)):: The Printer object OPTIONALLY returns the Job object's OPTIONAL "job-state-message" attribute. If the Printer object supports this attribute then it MUST be returned in the response. If this attribute is not returned in the response, the client can assume that the "job-state-message" attribute is not supported and will not be returned in a subsequent Job object query.

"number-of-intervening-jobs" (integer(0:MAX)):

The Printer object OPTIONALLY returns the Job object's OPTIONAL "number-of-intervening-jobs" attribute. If the Printer object supports this attribute then it MUST be returned in the response. If this attribute is not returned in the response, the client can assume that the "number-of-intervening-jobs" attribute is not supported and will not be returned in a subsequent Job object query.

Note: Since any printer state information which affects a job's state is reflected in the "job-state" and "job-state-reasons" attributes, it is sufficient to return only these attributes and no specific printer status attributes.

Note: In addition to the MANDATORY parameters required for every operation response, the simplest response consists of the just the "attributes-charset" and "attributes-natural-language" operation attributes and the "job-uri", "job-id", and "job-state" Job Object Attributes. In this simplest case, the status code is 'successful- ok' and there is no "status-message" or "detailed-status-message" operation attribute.

3.2.2 Print-URI Operation

This OPTIONAL operation is identical to the Print-Job operation (section 3.2.1) except that a client supplies a URI reference to the document data using the "document-uri" (uri) operation attribute (in Group 1) rather than including the document data itself. Before returning the response, the Printer MUST validate that the Printer supports the retrieval method (e.g., http, ftp, etc.) implied by the URI, and MUST check for valid URI syntax. If the client-supplied URI scheme is not supported, i.e. the value is not in the Printer object's "referenced-uri-scheme-supported" attribute, the Printer object MUST reject the request and return the 'client-error-uri- scheme-not-supported' status code.

The IPP Printer MAY validate the accessibility of the document as part of the operation or subsequently. If the Printer determines an accessibility problem before returning an operation response, it rejects the request and returns the 'client-error-document-access- error' status code. The Printer MAY also return a specific document access error code using the "document-access-error" operation attribute (see section 3.1.6.4).

If the Printer determines this document accessibility problem after accepting the request and returning an operation response with one of the successful status codes, the Printer adds the 'document-access- error' value to the job's "job-state-reasons" attribute and MAY populate the job's "job-document-access-errors" Job Description attribute (see section 4.3.11). See The Implementer's Guide [IPP- IIG] for suggested additional checks.

If the Printer object supports this operation, it MUST support the "reference-uri-schemes-supported" Printer attribute (see section 4.4.27).

It is up to the IPP object to interpret the URI and subsequently "pull" the document from the source referenced by the URI string.

3.2.3 Validate-Job Operation

This REQUIRED operation is similar to the Print-Job operation (section 3.2.1) except that a client supplies no document data and the Printer allocates no resources (i.e., it does not create a new Job object). This operation is used only to verify capabilities of a printer object against whatever attributes are supplied by the client in the Validate-Job request. By using the Validate-Job operation a client can validate that an identical Print-Job operation (with the document data) would be accepted. The Validate-Job operation also performs the same security negotiation as the Print-Job operation (see section 8), so that a client can check that the client and Printer object security requirements can be met before performing a Print-Job operation.

The Validate-Job operation does not accept a "document-uri" attribute in order to allow a client to check that the same Print-URI operation will be accepted, since the client doesn't send the data with the Print-URI operation. The client SHOULD just issue the Print-URI request.

The Printer object returns the same status codes, Operation Attributes (Group 1) and Unsupported Attributes (Group 2) as the Print-Job operation. However, no Job Object Attributes (Group 3) are returned, since no Job object is created.

3.2.4 Create-Job Operation

This OPTIONAL operation is similar to the Print-Job operation (section 3.2.1) except that in the Create-Job request, a client does not supply document data or any reference to document data. Also, the client does not supply any of the "document-name", "document- format", "compression", or "document-natural-language" operation attributes. This operation is followed by one or more Send-Document or Send-URI operations. In each of those operation requests, the client OPTIONALLY supplies the "document-name", "document-format", and "document-natural-language" attributes for each document in the multi-document Job object.

If a Printer object supports the Create-Job operation, it MUST also support the Send-Document operation and also MAY support the Send-URI operation.

If the Printer object supports this operation, it MUST support the "multiple-operation-time-out" Printer attribute (see section 4.4.31).

If the Printer object supports this operation, then it MUST support the "multiple-document-jobs-supported" Printer Description attribute (see section 4.4.16) and indicate whether or not it supports multiple-document jobs.

If the Printer object supports this operation and supports multiple documents in a job, then it MUST support the "multiple-document- handling" Job Template job attribute with at least one value (see section 4.2.4) and the associated "multiple-document-handling- default" and "multiple-document-handling-supported" Job Template Printer attributes (see section 4.2).

After the Create-Job operation has completed, the value of the "job- state" attribute is similar to the "job-state" after a Print-Job, even though no document-data has arrived. A Printer MAY set the 'job-data-insufficient' value of the job's "job-state-reason" attribute to indicate that processing cannot begin until sufficient data has arrived and set the "job-state" to either 'pending' or 'pending-held'. A non-spooling printer that doesn't implement the 'pending' job state may even set the "job-state" to 'processing', even though there is not yet any data to process. See sections 4.3.7 and 4.3.8.

3.2.5 Get-Printer-Attributes Operation

   This REQUIRED operation allows a client to request the values of the
   attributes of a Printer object.   In the request, the client supplies
   the set of Printer attribute names and/or attribute group names in
   which the requester is interested.  In the response, the Printer
   object returns a corresponding attribute set with the appropriate
   attribute values filled in.

For Printer objects, the possible names of attribute groups are:

      - 'job-template': the subset of the Job Template attributes that
        apply to a Printer object (the last two columns of the table in
        Section 4.2) that the implementation supports for Printer
        objects.
      - 'printer-description': the subset of the attributes specified in
        Section 4.4 that the implementation supports for Printer
        objects.

'all': the special group 'all' that includes all attributes that the implementation supports for Printer objects.

Since a client MAY request specific attributes or named groups, there is a potential that there is some overlap. For example, if a client requests, 'printer-name' and 'all', the client is actually requesting the "printer-name" attribute twice: once by naming it explicitly, and once by inclusion in the 'all' group. In such cases, the Printer object NEED NOT return each attribute only once in the response even if it is requested multiple times. The client SHOULD NOT request the same attribute in multiple ways.

It is NOT REQUIRED that a Printer object support all attributes belonging to a group (since some attributes are OPTIONAL). However, it is REQUIRED that each Printer object support all group names.

3.2.5.1 Get-Printer-Attributes Request

The following sets of attributes are part of the Get-Printer- Attributes Request:

Group 1: Operation Attributes

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:: The "printer-uri" (uri) operation attribute which is the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

"requested-attributes" (1setOf keyword):: The client OPTIONALLY supplies a set of attribute names and/or attribute group names in whose values the requester is interested. The Printer object MUST support this attribute. If the client omits this attribute, the Printer MUST respond as if this attribute had been supplied with a value of 'all'.

"document-format" (mimeMediaType):

The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. This attribute is useful for a Printer object to determine the set of supported attribute values that relate to the requested document format. The Printer object MUST return the attributes and values that it uses to validate a job on a create or Validate-Job operation in which this document format is supplied. The Printer object SHOULD return only (1) those attributes that are supported for the specified format and (2) the attribute values that are supported for the specified document format. By specifying the document format, the client can get the Printer object to eliminate the attributes and values that are not supported for a specific document format. For example, a Printer object might have multiple interpreters to support both 'application/postscript' (for PostScript) and 'text/plain' (for text) documents. However, for only one of those interpreters might the Printer object be able to support "number-up" with values of '1', '2', and '4'. For the other interpreter it might be able to only support "number-up" with a value of '1'. Thus a client can use the Get-Printer-Attributes operation to obtain the attributes and values that will be used to accept/reject a create job operation.

If the Printer object does not distinguish between different sets of supported values for each different document format when validating jobs in the create and Validate-Job operations, it MUST NOT distinguish between different document formats in the Get-Printer-Attributes operation. If the Printer object does distinguish between different sets of supported values for each different document format specified by the client, this specialization applies only to the following Printer object attributes:

      - Printer attributes that are Job Template attributes ("xxx-
        default" "xxx-supported", and "xxx-ready" in the Table in
        Section 4.2),
      - "pdl-override-supported",
      - "compression-supported",
      - "job-k-octets-supported",
      - "job-impressions-supported",
      - "job-media-sheets-supported",
      - "printer-driver-installer",
      - "color-supported", and
      - "reference-uri-schemes-supported"

The values of all other Printer object attributes (including "document-format-supported") remain invariant with respect to the client supplied document format (except for new Printer description attribute as registered according to section 6.2).

If the client omits this "document-format" operation attribute, the Printer object MUST respond as if the attribute had been supplied with the value of the Printer object's "document-format- default" attribute. It is RECOMMENDED that the client always supply a value for "document-format", since the Printer object's "document-format-default" may be 'application/octet-stream', in which case the returned attributes and values are for the union of the document formats that the Printer can automatically sense. For more details, see the description of the 'mimeMediaType' attribute syntax in section 4.1.9.

If the client supplies a value for the "document-format" Operation attribute that is not supported by the Printer, i.e., is not among the values of the Printer object's "document-format-supported" attribute, the Printer object MUST reject the operation and return the 'client-error-document-format-not-supported' status code.

3.2.5.2 Get-Printer-Attributes Response

The Printer object returns the following sets of attributes as part of the Get-Printer-Attributes Response:

Group 1: Operation Attributes

Status Message:

        In addition to the REQUIRED status code returned in every
        response, the response OPTIONALLY includes a "status-message"
        (text(255)) and/or a "detailed-status-message" (text(MAX))
        operation attribute as described in sections 13 and  3.1.6.

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

The response NEED NOT contain the "requested-attributes" operation attribute with any supplied values (attribute keywords) that were requested by the client but are not supported by the IPP object. If the Printer object does return unsupported attributes referenced in the "requested-attributes" operation attribute and that attribute included group names, such as 'all', the unsupported attributes MUST NOT include attributes described in the standard but not supported by the implementation.

Group 3: Printer Object Attributes

This is the set of requested attributes and their current values. The Printer object ignores (does not respond with) any requested attribute which is not supported. The Printer object MAY respond with a subset of the supported attributes and values, depending on the security policy in force. However, the Printer object MUST respond with the 'unknown' value for any supported attribute (including all REQUIRED attributes) for which the Printer object does not know the value. Also the Printer object MUST respond with the 'no-value' for any supported attribute (including all REQUIRED attributes) for which the system administrator has not configured a value. See the description of the "out-of-band" values in the beginning of Section 4.1.

3.2.6 Get-Jobs Operation

This REQUIRED operation allows a client to retrieve the list of Job objects belonging to the target Printer object. The client may also supply a list of Job attribute names and/or attribute group names. A group of Job object attributes will be returned for each Job object that is returned.

This operation is similar to the Get-Job-Attributes operation, except that this Get-Jobs operation returns attributes from possibly more than one object.

3.2.6.1 Get-Jobs Request

The client submits the Get-Jobs request to a Printer object.

The following groups of attributes are part of the Get-Jobs Request:

Group 1: Operation Attributes

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:: The "printer-uri" (uri) operation attribute which is the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

"limit" (integer(1:MAX)):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It is an integer value that determines the maximum number of jobs that a client will receive from the Printer even if "which-jobs" or "my-jobs" constrain which jobs are returned. The limit is a "stateless limit" in that if the value supplied by the client is 'N', then only the first 'N' jobs are returned in the Get-Jobs Response. There is no mechanism to allow for the next 'M' jobs after the first 'N' jobs. If the client does not supply this attribute, the Printer object responds with all applicable jobs.

"requested-attributes" (1setOf type2 keyword):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It is a set of Job attribute names and/or attribute groups names in whose values the requester is interested. This set of attributes is returned for each Job object that is returned. The allowed attribute group names are the same as those defined in the Get-Job-Attributes operation in section 3.3.4. If the client does not supply this attribute, the Printer MUST respond as if the client had supplied this attribute with two values: 'job- uri' and 'job-id'.

"which-jobs" (type2 keyword):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It indicates which Job objects MUST be returned by the Printer object. The values for this attribute are:

      'completed': This includes any Job object whose state is
         'completed', 'canceled', or 'aborted'.
      'not-completed': This includes any Job object whose state is
         'pending', 'processing', 'processing-stopped', or 'pending-
         held'.

A Printer object MUST support both values. However, if the implementation does not keep jobs in the 'completed', 'canceled', and 'aborted' states, then it returns no jobs when the 'completed' value is supplied.

If a client supplies some other value, the Printer object MUST copy the attribute and the unsupported value to the Unsupported Attributes response group, reject the request, and return the 'client-error-attributes-or-values-not-supported' status code.

If the client does not supply this attribute, the Printer object MUST respond as if the client had supplied the attribute with a value of 'not-completed'.

"my-jobs" (boolean):: The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It indicates whether jobs from all users or just the jobs submitted by the requesting user of this request MUST be considered as candidate jobs to be returned by the Printer object. If the client does not supply this attribute, the Printer object MUST respond as if the client had supplied the attribute with a value of 'false', i.e., jobs from all users. The means for authenticating the requesting user and matching the jobs is described in section 8.

3.2.6.2 Get-Jobs Response

The Printer object returns all of the Job objects up to the number specified by the "limit" attribute that match the criteria as defined by the attribute values supplied by the client in the request. It is possible that no Job objects are returned since there may literally be no Job objects at the Printer, or there may be no Job objects that match the criteria supplied by the client. If the client requests any Job attributes at all, there is a set of Job Object Attributes returned for each Job object.

It is not an error for the Printer to return 0 jobs. If the response returns 0 jobs because there are no jobs matching the criteria, and the request would have returned 1 or more jobs with a status code of 'successful-ok' if there had been jobs matching the criteria, then the status code for 0 jobs MUST be 'successful-ok'.

Group 1: Operation Attributes

Status Message:

In addition to the REQUIRED status code returned in every response, the response OPTIONALLY includes a "status-message" (text(255)) and/or a "detailed-status-message" (text(MAX)) operation attribute as described in sections 13 and 3.1.6.

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

Groups 3 to N: Job Object Attributes

The Printer object responds with one set of Job Object Attributes for each returned Job object. The Printer object ignores (does not respond with) any requested attribute or value which is not supported or which is restricted by the security policy in force, including whether the requesting user is the user that submitted the job (job originating user) or not (see section 8). However, the Printer object MUST respond with the 'unknown' value for any supported attribute (including all REQUIRED attributes) for which the Printer object does not know the value, unless it would violate the security policy. See the description of the "out-of- band" values in the beginning of Section 4.1.

Jobs are returned in the following order:

      - If the client requests all 'completed' Jobs (Jobs in the
        'completed', 'aborted', or 'canceled' states), then the Jobs are
        returned newest to oldest (with respect to actual completion
        time)
      - If the client requests all 'not-completed' Jobs (Jobs in the
        'pending', 'processing', 'pending-held', and 'processing-
        stopped' states), then Jobs are returned in relative
        chronological order of expected time to complete (based on
        whatever scheduling algorithm is configured for the Printer
        object).

3.2.7 Pause-Printer Operation

This OPTIONAL operation allows a client to stop the Printer object from scheduling jobs on all its devices. Depending on implementation, the Pause-Printer operation MAY also stop the Printer from processing the current job or jobs. Any job that is currently being printed is either stopped as soon as the implementation permits or is completed, depending on implementation. The Printer object MUST still accept create operations to create new jobs, but MUST prevent any jobs from entering the 'processing' state.

If the Pause-Printer operation is supported, then the Resume-Printer operation MUST be supported, and vice-versa.

The IPP Printer stops the current job(s) on its device(s) that were in the 'processing' or 'processing-stopped' states as soon as the implementation permits. If the implementation will take appreciable time to stop, the IPP Printer adds the 'moving-to-paused' value to the Printer object's "printer-state-reasons" attribute (see section 4.4.12). When the device(s) have all stopped, the IPP Printer transitions the Printer object to the 'stopped' state, removes the 'moving-to-paused' value, if present, and adds the 'paused' value to the Printer object's "printer-state-reasons" attribute.

When the current job(s) complete that were in the 'processing' state, the IPP Printer transitions them to the 'completed' state. When the current job(s) stop in mid processing that were in the 'processing' state, the IPP Printer transitions them to the 'processing-stopped' state and adds the 'printer-stopped' value to the job's "job-state- reasons" attribute.

For any jobs that are 'pending' or 'pending-held', the 'printer- stopped' value of the jobs' "job-state-reasons" attribute also applies. However, the IPP Printer NEED NOT update those jobs' "job- state-reasons" attributes and only need return the 'printer-stopped' value when those jobs are queried (so-called "lazy evaluation").

Whether the Pause-Printer operation affects jobs that were submitted to the device from other sources than the IPP Printer object in the same way that the Pause-Printer operation affects jobs that were submitted to the IPP Printer object using IPP, depends on implementation, i.e., on whether the IPP protocol is being used as a universal management protocol or just to manage IPP jobs, respectively.

The IPP Printer MUST accept the request in any state and transition the Printer to the indicated new "printer-state" before returning as follows:

     Current        New      "printer   IPP Printer's response status
    "printer-    "printer-   -state-          code and action:
     state"       state"    reasons"
  
  'idle'       'stopped'    'paused'  'successful-ok'
  'processing' 'processing' 'moving-  OPTION 1: 'successful-ok';
                              to-       Later, when all output has
                              paused'   stopped, the "printer-state"
                                        becomes 'stopped', and the
                                        'paused' value replaces the
                                        'moving-to-paused' value in the
                                        "printer-state-reasons"
                                        attribute
  'processing' 'stopped'    'paused'  OPTION 2: 'successful-ok';
                                        all device output stopped
                                        immediately
  'stopped'    'stopped'    'paused'  'successful-ok'
  
   Access Rights: The authenticated user (see section 8.3) performing
   this operation must be an operator or administrator of the Printer
   object (see Sections 1 and 8.5).   Otherwise, the IPP Printer MUST
   reject the operation and return:  'client-error-forbidden', 'client-
   error-not-authenticated', or 'client-error-not-authorized' as
   appropriate.

3.2.7.1 Pause-Printer Request

The following groups of attributes are part of the Pause-Printer Request:

Group 1: Operation Attributes

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:

The "printer-uri" (uri) operation attribute which is the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be supplied by the client as described in section 8.3.

3.2.7.2 Pause-Printer Response

The following groups of attributes are part of the Pause-Printer Response:

Group 1: Operation Attributes

Status Message:

        In addition to the REQUIRED status code returned in every
        response, the response OPTIONALLY includes a "status-message"
        (text(255)) and/or a "detailed-status-message" (text(MAX))
        operation attribute as described in sections 13 and  3.1.6.

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

3.2.8 Resume-Printer Operation

This operation allows a client to resume the Printer object scheduling jobs on all its devices. The Printer object MUST remove the 'paused' and 'moving-to-paused' values from the Printer object's "printer-state-reasons" attribute, if present. If there are no other reasons to keep a device paused (such as media-jam), the IPP Printer is free to transition itself to the 'processing' or 'idle' states, depending on whether there are jobs to be processed or not, respectively, and the device(s) resume processing jobs.

If the Pause-Printer operation is supported, then the Resume-Printer operation MUST be supported, and vice-versa.

The IPP Printer removes the 'printer-stopped' value from any job's "job-state-reasons" attributes contained in that Printer.

The IPP Printer MUST accept the request in any state, transition the Printer object to the indicated new state as follows:

     Current    New "printer-  IPP Printer's response status code and
    "printer-      state"                     action:
      state"
   
   'idle'       'idle'         'successful-ok'
   'processing' 'processing'   'successful-ok'
   
   'stopped'    'processing'   'successful-ok';
                               when there are jobs to be processed
   'stopped'    'idle'         'successful-ok';
                               when there are no jobs to be processed.
   
   Access Rights: The authenticated user (see section 8.3) performing
   this operation must be an operator or administrator of the Printer
   object (see Sections 1 and 8.5).  Otherwise, the IPP Printer MUST
   reject the operation and return:  'client-error-forbidden', 'client-
   error-not-authenticated', or 'client-error-not-authorized' as
   appropriate.

The Resume-Printer Request and Resume-Printer Response have the same attribute groups and attributes as the Pause-Printer operation (see sections 3.2.7.1 and 3.2.7.2).

3.2.9 Purge-Jobs Operation

This OPTIONAL operation allows a client to remove all jobs from an IPP Printer object, regardless of their job states, including jobs in the Printer object's Job History (see Section 4.3.7.2). After a Purge-Jobs operation has been performed, a Printer object MUST return no jobs in subsequent Get-Job-Attributes and Get-Jobs responses (until new jobs are submitted).

Whether the Purge-Jobs (and Get-Jobs) operation affects jobs that were submitted to the device from other sources than the IPP Printer object in the same way that the Purge-Jobs operation affects jobs that were submitted to the IPP Printer object using IPP, depends on implementation, i.e., on whether the IPP protocol is being used as a universal management protocol or just to manage IPP jobs, respectively.

   Note:  if an operator wants to cancel all jobs without clearing out
   the Job History, the operator uses the Cancel-Job operation on each
   job instead of using the Purge-Jobs operation.

The Printer object MUST accept this operation in any state and transition the Printer object to the 'idle' state.

Access Rights: The authenticated user (see section 8.3) performing this operation must be an operator or administrator of the Printer object (see Sections 1 and 8.5). Otherwise, the IPP object MUST reject the operation and return: client-error-forbidden, client- error-not-authenticated, and client-error-not-authorized as appropriate.

The Purge-Jobs Request and Purge-Jobs Response have the same attribute groups and attributes as the Pause-Printer operation (see sections 3.2.7.1 and 3.2.7.2).

3.3 Job Operations

All Job operations are directed at Job objects. A client MUST always supply some means of identifying the Job object in order to identify the correct target of the operation. That job identification MAY either be a single Job URI or a combination of a Printer URI with a Job ID. The IPP object implementation MUST support both forms of identification for every job.

3.3.1 Send-Document Operation

This OPTIONAL operation allows a client to create a multi-document Job object that is initially "empty" (contains no documents). In the Create-Job response, the Printer object returns the Job object's URI (the "job-uri" attribute) and the Job object's 32-bit identifier (the "job-id" attribute). For each new document that the client desires to add, the client uses a Send-Document operation. Each Send- Document Request contains the entire stream of document data for one document.

If the Printer supports this operation but does not support multiple documents per job, the Printer MUST reject subsequent Send-Document operations supplied with data and return the 'server-error-multiple- document-jobs-not-supported'. However, the Printer MUST accept the first document with a 'true' or 'false' value for the "last-document" operation attribute (see below), so that clients MAY always submit one document jobs with a 'false' value for "last-document" in the first Send-Document and a 'true' for "last-document" in the second Send-Document (with no data).

Since the Create-Job and the send operations (Send-Document or Send- URI operations) that follow could occur over an arbitrarily long period of time for a particular job, a client MUST send another send operation within an IPP Printer defined minimum time interval after the receipt of the previous request for the job. If a Printer object supports the Create-Job and Send-Document operations, the Printer object MUST support the "multiple-operation-time-out" attribute (see section 4.4.31). This attribute indicates the minimum number of seconds the Printer object will wait for the next send operation before taking some recovery action.

An IPP object MUST recover from an errant client that does not supply a send operation, sometime after the minimum time interval specified by the Printer object's "multiple-operation-time-out" attribute. Such recovery MAY include any of the following or other recovery actions:

      1. Assume that the Job is an invalid job, start the process of
         changing the job state to 'aborted', add the 'aborted-by-
         system' value to the job's "job-state-reasons" attribute (see
         section 4.3.8), and clean up all resources associated with the
         Job.  In this case, if another send operation is finally
         received, the Printer responds with an "client-error-not-
         possible" or "client-error-not-found" depending on whether or
         not the Job object is still around when the send operation
         finally arrives.
      2. Assume that the last send operation received was in fact the
         last document (as if the "last-document" flag had been set to
         'true'), close the Job object, and proceed to process it (i.e.,
         move the Job's state to 'pending').
      3. Assume that the last send operation received was in fact the
         last document, close the Job, but move it to the 'pending-held'
         and add the 'submission-interrupted' value to the job's "job-
         state-reasons" attribute (see section 4.3.8).  This action
         allows the user or an operator to determine whether to continue
         processing the Job by moving it back to the 'pending' state
         using the Release-Job operation (see section 3.3.6) or to
         cancel the job using the Cancel-Job operation (see section
         3.3.3).
   
   Each implementation is free to decide the "best" action to take
   depending on local policy, whether any documents have been added,
   whether the implementation spools jobs or not,  and/or any other
   piece of information available to it.  If the choice is to abort the
   Job object, it is possible that the Job object may already have been
   processed to the point that some media sheet pages have been printed.

Access Rights: The authenticated user (see section 8.3) performing this operation must either be the job owner (as determined in the Create-Job operation) or an operator or administrator of the Printer object (see Sections 1 and 8.5). Otherwise, the IPP object MUST reject the operation and return: 'client-error-forbidden', 'client- error-not-authenticated', or 'client-error-not-authorized' as appropriate.

3.3.1.1 Send-Document Request

The following attribute sets are part of the Send-Document Request:

Group 1: Operation Attributes

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:

Either (1) the "printer-uri" (uri) plus "job-id" (integer(1:MAX))or (2) the "job-uri" (uri) operation attribute(s) which define the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be supplied by the client as described in section 8.3.

"document-name" (name(MAX)):

The client OPTIONALLY supplies this attribute. The Printer object MUST support this attribute. It contains the client supplied document name. The document name MAY be different than the Job name. It might be helpful, but NEED NOT be unique across multiple documents in the same Job. Typically, the client software automatically supplies the document name on behalf of the end user by using a file name or an application generated name. See the description of the "document-name" operation attribute in the Print-Job Request (section 3.2.1.1) for more information about this attribute.

"compression" (type3 keyword):

See the description of "compression" for the Print-Job operation in Section 3.2.1.1.

"document-format" (mimeMediaType):

See the description of "document-format" for the Print-Job operation in Section 3.2.1.1.

"document-natural-language" (naturalLanguage):

The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute. This attribute specifies the natural language of the document for those document-formats that require a specification of the natural language in order to image the document unambiguously. There are no particular values required for the Printer object to support.

"last-document" (boolean):

The client MUST supply this attribute. The Printer object MUST support this attribute. It is a boolean flag that is set to 'true' if this is the last document for the Job, 'false' otherwise.

Group 2: Document Content

The client MUST supply the document data if the "last-document" flag is set to 'false'. However, since a client might not know that the previous document sent with a Send-Document (or Send-URI) operation was the last document (i.e., the "last-document" attribute was set to 'false'), it is legal to send a Send-Document request with no document data where the "last-document" flag is set to 'true'. Such a request MUST NOT increment the value of the Job object's "number-of-documents" attribute, since no real document was added to the job. It is not an error for a client to submit a job with no actual document data, i.e., only a single Create-Job and Send-Document request with a "last-document" operation attribute set to 'true' with no document data.

3.3.1.2 Send-Document Response

The following sets of attributes are part of the Send-Document Response:

Group 1: Operation Attributes

Status Message:: In addition to the REQUIRED status code returned in every response, the response OPTIONALLY includes a "status-message" (text(255)) and/or a "detailed-status-message" (text(MAX)) operation attribute as described in sections 13 and 3.1.6.

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

Group 3: Job Object Attributes

This is the same set of attributes as described in the Print-Job response (see section 3.2.1.2).

3.3.2 Send-URI Operation

   This OPTIONAL operation is identical to the Send-Document operation
   (see section 3.3.1) except that a client MUST supply a URI reference
   ("document-uri" operation attribute) rather than the document data
   itself.  If a Printer object supports this operation, clients can use
   both Send-URI or Send-Document operations to add new documents to an
   existing multi-document Job object.  However, if a client needs to
   indicate that the previous Send-URI or Send-Document was the last
   document,  the client MUST use the Send-Document operation with no
   document data and the "last-document" flag set to 'true' (rather than
   using a Send-URI operation with no "document-uri" operation
   attribute).

If a Printer object supports this operation, it MUST also support the Print-URI operation (see section 3.2.2).

The Printer object MUST validate the syntax and URI scheme of the supplied URI before returning a response, just as in the Print-URI operation. The IPP Printer MAY validate the accessibility of the document as part of the operation or subsequently (see section 3.2.2).

3.3.3 Cancel-Job Operation

This REQUIRED operation allows a client to cancel a Print Job from the time the job is created up to the time it is completed, canceled, or aborted. Since a Job might already be printing by the time a Cancel-Job is received, some media sheet pages might be printed before the job is actually terminated.

The IPP object MUST accept or reject the request based on the job's current state and transition the job to the indicated new state as follows:

       Current "job-    New "job-     IPP object's response status
           state"         state"             code and action:
      
      'pending'       'canceled'     'successful-ok'
      'pending-held'  'canceled'     'successful-ok'
      'processing'    'canceled'     'successful-ok'
      'processing'    'processing'   'successful-ok'  See Rule 1
      'processing'    'processing'   'client-error-not-possible'
                                     See Rule 2
      'processing-    'canceled'     'successful-ok'
      stopped'
      'processing-    'processing-   'successful-ok'  See Rule 1
      stopped'        stopped'
      'processing-    'processing-   'client-error-not-possible'
      stopped'        stopped'       See Rule 2
      'completed'     'completed'    'client-error-not-possible'
      'canceled'      'canceled'     'client-error-not-possible'
      'aborted'       'aborted'      'client-error-not-possible'
   
   Rule 1:  If the implementation requires some measurable time to
   cancel the job in the 'processing' or 'processing-stopped' job
   states, the IPP object MUST add the 'processing-to-stop-point' value
   to the job's "job-state-reasons" attribute and then transition the
   job to the 'canceled' state when the processing ceases (see section
   4.3.8).
   
   Rule 2:  If the Job object already has the 'processing-to-stop-point'
   value in its "job-state-reasons" attribute, then the Printer object
   MUST reject a Cancel-Job operation.
   
   Access Rights: The authenticated user (see section 8.3) performing
   this operation must either be the job owner or an operator or
   administrator of the Printer object (see Sections 1 and 8.5).
   Otherwise, the IPP object MUST reject the operation and return:
    'client-error-forbidden', 'client-error-not-authenticated', or
   'client-error-not-authorized' as appropriate.

3.3.3.1 Cancel-Job Request

The following groups of attributes are part of the Cancel-Job Request:

Group 1: Operation Attributes

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:: Either (1) the "printer-uri" (uri) plus "job-id" (integer(1:MAX))or (2) the "job-uri" (uri) operation attribute(s) which define the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

"message" (text(127)):: The client OPTIONALLY supplies this attribute. The Printer object OPTIONALLY supports this attribute. It is a message to the operator. This "message" attribute is not the same as the "job-message-from-operator" attribute. That attribute is used to report a message from the operator to the end user that queries that attribute. This "message" operation attribute is used to send a message from the client to the operator along with the operation request. It is an implementation decision of how or where to display this message to the operator (if at all).

3.3.3.2 Cancel-Job Response

The following sets of attributes are part of the Cancel-Job Response:

Group 1: Operation Attributes

Status Message:: In addition to the REQUIRED status code returned in every response, the response OPTIONALLY includes a "status-message" (text(255)) and/or a "detailed-status-message" (text(MAX)) operation attribute as described in sections 13 and 3.1.6.

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

Once a successful response has been sent, the implementation guarantees that the Job will eventually end up in the 'canceled' state. Between the time of the Cancel-Job operation is accepted and when the job enters the 'canceled' job-state (see section 4.3.7), the "job-state-reasons" attribute SHOULD contain the 'processing-to- stop-point'
value which indicates to later queries that although the Job might still be 'processing', it will eventually end up in the 'canceled' state, not the 'completed' state.

3.3.4 Get-Job-Attributes Operation

This REQUIRED operation allows a client to request the values of attributes of a Job object and it is almost identical to the Get- Printer-Attributes operation (see section 3.2.5). The only differences are that the operation is directed at a Job object rather than a Printer object, there is no "document-format" operation attribute used when querying a Job object, and the returned attribute group is a set of Job object attributes rather than a set of Printer object attributes.

For Jobs, the possible names of attribute groups are:

      - 'job-template': the subset of the Job Template attributes that
        apply to a Job object (the first column of the table in Section
        4.2) that the implementation supports for Job objects.
      - 'job-description': the subset of the Job Description attributes
        specified in Section 4.3 that the implementation supports for
        Job objects.
      - 'all': the special group 'all' that includes all attributes that
        the implementation supports for Job objects.

Since a client MAY request specific attributes or named groups, there is a potential that there is some overlap. For example, if a client requests, 'job-name' and 'job-description', the client is actually requesting the "job-name" attribute once by naming it explicitly, and once by inclusion in the 'job-description' group. In such cases, the Printer object NEED NOT return the attribute only once in the response even if it is requested multiple times. The client SHOULD NOT request the same attribute in multiple ways.

It is NOT REQUIRED that a Job object support all attributes belonging to a group (since some attributes are OPTIONAL). However it is REQUIRED that each Job object support all these group names.

3.3.4.1 Get-Job-Attributes Request

The following groups of attributes are part of the Get-Job-Attributes Request when the request is directed at a Job object:

Group 1: Operation Attributes

Natural Language and Character Set:

The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.1.

Target:

Either (1) the "printer-uri" (uri) plus "job-id" (integer(1:MAX)) or (2) the "job-uri" (uri) operation attribute(s) which define the target for this operation as described in section 3.1.5.

Requesting User Name:

The "requesting-user-name" (name(MAX)) attribute SHOULD be supplied by the client as described in section 8.3.

"requested-attributes" (1setOf keyword):

        The client OPTIONALLY supplies this attribute.  The IPP object
        MUST support this attribute.   It is a set of attribute names
        and/or attribute group names in whose values the requester is
        interested.  If the client omits this attribute, the IPP object
        MUST respond as if this attribute had been supplied with a value
        of 'all'.

3.3.4.2 Get-Job-Attributes Response

The Printer object returns the following sets of attributes as part of the Get-Job-Attributes Response:

Group 1: Operation Attributes

Status Message:: In addition to the REQUIRED status code returned in every response, the response OPTIONALLY includes a "status-message" (text(255)) and/or a "detailed-status-message" (text(MAX)) operation attribute as described in sections 13 and 3.1.6.

Natural Language and Character Set:: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.4.2. The "attributes- natural-language" MAY be the natural language of the Job object, rather than the one requested.

Group 2: Unsupported Attributes

See section 3.1.7 for details on returning Unsupported Attributes.

Group 3: Job Object Attributes

This is the set of requested attributes and their current values. The IPP object ignores (does not respond with) any requested attribute or value which is not supported or which is restricted by the security policy in force, including whether the requesting user is the user that submitted the job (job originating user) or not (see section 8). However, the IPP object MUST respond with the 'unknown' value for any supported attribute (including all REQUIRED attributes) for which the IPP object does not know the value, unless it would violate the security policy. See the description of the "out-of-band" values in the beginning of Section 4.1.

3.3.5 Hold-Job Operation

This OPTIONAL operation allows a client to hold a pending job in the queue so that it is not eligible for scheduling. If the Hold-Job operation is supported, then the Release-Job operation MUST be supported, and vice-versa. The OPTIONAL "job-hold-until" operation attribute allows a client to specify whether to hold the job indefinitely or until a specified time period, if supported.

The IPP object MUST accept or reject the request based on the job's current state and transition the job to the indicated new state as follows:

        Current "job-     New "job-state"   IPP object's response status
            state"                                 code and action:
      
      'pending'         'pending-held'     'successful-ok'  See Rule 1
      'pending'         'pending'          'successful-ok'  See Rule 2
      'pending-held'    'pending-held'     'successful-ok'  See Rule 1
      'pending-held'    'pending'          'successful-ok'  See Rule 2
      'processing'      'processing'       'client-error-not-possible'
      'processing-      'processing-       'client-error-not-possible'
      stopped'          stopped'
      'completed'       'completed'        'client-error-not-possible'
      'canceled'        'canceled'         'client-error-not-possible'
      'aborted'         'aborted'          'client-error-not-possible'
   
   Rule 1:  If the implementation supports multiple reasons for a job to
   be in the 'pending-held' state, the IPP object MUST add the 'job-
   hold-until-specified' value to the job's "job-state-reasons"
   attribute.
   
   Rule 2:  If the IPP object supports the "job-hold-until" operation
   attribute, but the specified time period has already started (or is
   the 'no-hold' value) and there are no other reasons to hold the job,
   the IPP object MUST make the job be a candidate for processing
   immediately (see Section 4.2.2) by putting the job in the 'pending'
   state.
   
   Note:  In order to keep the Hold-Job operation simple, such a request
   is rejected when the job is in the 'processing' or 'processing-
   stopped' states.  If an operation is needed to hold jobs while in
   these states, it will be added as an additional operation, rather
   than overloading the Hold-Job operation.  Then it is clear to clients
   by querying the Printer object's "operations-supported" (see Section
   4.4.15) and the Job object's "job-state" (see Section 4.3.7)
   attributes which operations are possible.

Access Rights: The authenticated user (see section 8.3) performing this operation must either be the job owner or an operator or administrator of the Printer object (see Sections 1 and 8.5). Otherwise, the IPP object MUST reject the operation and return: 'client-error-forbidden', 'client-error-not-authenticated', or 'client-error-not-authorized' as appropriate.

3.3.5.1 Hold-Job Request

The groups and operation attributes are the same as for a Cancel-Job request (see section 3.3.3.1), with the addition of the following Group 1 Operation attribute:

"job-hold-until" (type3 keyword | name(MAX)):

The client OPTIONALLY supplies this Operation attribute. The IPP object MUST support this operation attribute in a Hold-Job request, if it supports the "job-hold-until" Job template attribute in create operations. See section 4.2.2. The IPP object SHOULD support the "job-hold-until" Job Template attribute for use in job create operations with at least the 'indefinite' value, if it supports the Hold-Job operation. Otherwise, a client cannot create a job and hold it immediately (without picking some supported time period in the future).

If supplied and supported as specified in the Printer's "job- hold-until-supported" attribute, the IPP object copies the supplied operation attribute to the Job object, replacing the job's previous "job-hold-until" attribute, if present, and makes the job a candidate for scheduling during the supplied named time period.

If supplied, but either the "job-hold-until" Operation attribute itself or the value supplied is not supported, the IPP object accepts the request, returns the unsupported attribute or value in the Unsupported Attributes Group according to section 3.1.7, returns the 'successful-ok- ignored-or-substituted-attributes, and holds the job indefinitely until a client performs a subsequent Release-Job operation.

If the client (1) supplies a value that specifies a time period that has already started or the 'no-hold' value (meaning don't hold the job) and (2) the IPP object supports the "job-hold- until" operation attribute and there are no other reasons to hold the job, the IPP object MUST accept the operation and make the job be a candidate for processing immediately (see Section 4.2.2).

If the client does not supply a "job-hold-until" Operation attribute in the request, the IPP object MUST populate the job object with a "job-hold-until" attribute with the 'indefinite' value (if IPP object supports the "job-hold-until" attribute) and hold the job indefinitely, until a client performs a Release-Job operation.

3.3.5.2 Hold-Job Response

The groups and attributes are the same as for a Cancel-Job response (see section 3.3.3.2).

3.3.6 Release-Job Operation

This OPTIONAL operation allows a client to release a previously held job so that it is again eligible for scheduling. If the Hold-Job operation is supported, then the Release-Job operation MUST be supported, and vice-versa.

This operation removes the "job-hold-until" job attribute, if present, from the job object that had been supplied in the create or most recent Hold-Job or Restart-Job operation and removes its effect on the job. The IPP object MUST remove the 'job-hold-until- specified' value from the job's "job-state-reasons" attribute, if present. See section 4.3.8.

The IPP object MUST accept or reject the request based on the job's current state and transition the job to the indicated new state as follows:

Current "job- New "job-state" IPP object's response status

state" code and action:

      'pending'        'pending'        'successful-ok'
                                         No effect on the job.
      'pending-held'   'pending-held'   'successful-ok'  See Rule 1
      'pending-held'   'pending'        'successful-ok'
      'processing'     'processing'     'successful-ok'
                                         No effect on the job.
      'processing-     'processing-     'successful-ok'
       stopped'         stopped'         No effect on the job.
      'completed'      'completed'      'client-error-not-possible'
      'canceled'       'canceled'       'client-error-not-possible'
      'aborted'        'aborted'        'client-error-not-possible'
   
   Rule 1:  If there are other reasons to keep the job in the 'pending-
   held' state, such as 'resources-are-not-ready', the job remains in
   the 'pending-held' state.  Thus the 'pending-held' state is not just
   for jobs that have the 'job-hold-until' applied to them, but are for
   any reason to keep the job from being a candidate for scheduling and
   processing, such as 'resources-are-not-ready'.  See the "job-hold-
   until" attribute (section 4.2.2).

The Release-Job Request and Release-Job Response have the same attribute groups and attributes as the Cancel-Job operation (see section 3.3.3.1 and 3.3.3.2).

3.3.7 Restart-Job Operation

This OPTIONAL operation allows a client to restart a job that is retained in the queue after processing has completed (see section 4.3.7.2).

The job is moved to the 'pending' or 'pending-held' job state and restarts at the beginning on the same IPP Printer object with the same attribute values. If any of the documents in the job were passed by reference (Print-URI or Send-URI), the Printer MUST re- fetch the data, since the semantics of Restart-Job are to repeat all Job processing. The Job Description attributes that accumulate job progress, such as "job-impressions-completed", "job-media-sheets- completed", and "job-k-octets-processed", MUST be reset to 0 so that they give an accurate record of the job from its restart point. The job object MUST continue to use the same "job-uri" and "job-id" attribute values.

   Note:  If in the future an operation is needed that does not reset
   the job progress attributes, then a new operation will be defined
   which makes a copy of the job, assigns a new "job-uri" and "job-id"
   to the copy and resets the job progress attributes in the new copy
   only.

The IPP object MUST accept or reject the request based on the job's current state, transition the job to the indicated new state as follows:

Current "job- New "job-state" IPP object's response status

state" code and action:

      'pending'        'pending'        'client-error-not-possible'
      'pending-held'   'pending-held'   'client-error-not-possible'
      'processing'     'processing'     'client-error-not-possible'
      'processing-     'processing-     'client-error-not-possible'
      stopped'         stopped'
      'completed'      'pending' or     'successful-ok' - job is started
                        'pending-held'   over.
      'completed'      'completed'      'client-error-not-possible' -
                                         see Rule 1
      'canceled'       'pending' or     'successful-ok' - job is started
                        'pending-held'   over.
      'canceled'       'canceled'       'client-error-not-possible' -
                                         see Rule 1
      'aborted'        'pending' or     'successful-ok' - job is started
                        'pending-held'   over.
      'aborted'        'aborted'        'client-error-not-possible' -
                                         see Rule 1
   
   Rule 1:  If the Job Retention Period has expired for the job in this
   state, then the IPP object rejects the operation.  See section
   4.3.7.2.
   
   Note:  In order to prevent a user from inadvertently restarting a job
   in the middle, the Restart-Job request is rejected when the job is in
   the 'processing' or 'processing-stopped' states.  If in the future an
   operation is needed to hold or restart jobs while in these states, it
   will be added as an additional operation, rather than overloading the
   Restart-Job operation, so that it is clear that the user intended
   that the current job not be completed.

3.3.7.1 Restart-Job Request

The groups and attributes are the same as for a Cancel-Job request (see section 3.3.3.1), with the addition of the following Group 1 Operation attribute:

"job-hold-until" (type3 keyword | name(MAX)):

The client OPTIONALLY supplies this attribute. The IPP object MUST support this Operation attribute in a Restart-Job request, if it supports the "job-hold-until" Job Template attribute in create operations. See section 4.2.2. Otherwise, the IPP object NEED NOT support the "job-hold-until" Operation attribute in a Restart-Job request.

If supplied and supported as specified in the Printer's "job- hold-until-supported" attribute, the IPP object copies the supplied Operation attribute to the Job object, replacing the job's previous "job-hold-until" attribute, if present, and makes the job a candidate for scheduling during the supplied named time period. See section 4.2.2.

If supplied, but the value is not supported, the IPP object accepts the request, returns the unsupported attribute or value in the Unsupported Attributes Group according to section 3.1.7, returns the 'successful-ok-ignored-or-substituted-attributes' status code, and holds the job indefinitely until a client performs a subsequent Release-Job operation.

If supplied, but the "job-hold-until" Operation attribute itself is not supported, the IPP object accepts the request, returns the unsupported attribute with the out-of-band 'unsupported' value in the Unsupported Attributes Group according to section 3.1.7, returns the 'successful-ok- ignored-or-substituted-attributes' status code, and restarts the job, i.e., ignores the "job-hold-until" attribute.

If the client (1) supplies a value that specifies a time period that has already started or the 'no-hold' value (meaning don't hold the job) and (2) the IPP object supports the "job-hold- until" operation attribute and there are no other reasons to hold the job, the IPP object makes the job a candidate for processing immediately (see Section 4.2.2).

If the client does not supply a "job-hold-until" operation attribute in the request, the IPP object removes the "job- hold-until" attribute, if present, from the job. If there are no other reasons to hold the job, the Restart-Job operation makes the job a candidate for processing immediately (see Section 4.2.2).

3.3.7.2 Restart-Job Response

The groups and attributes are the same as for a Cancel-Job response (see section 3.3.3.2).

   Note:  In the future an OPTIONAL Modify-Job or Set-Job-Attributes
   operation may be specified that allows the client to modify other
   attributes before releasing the restarted job.

4. Object Attributes

This section describes the attributes with their corresponding attribute syntaxes and values that are part of the IPP model. The sections below show the objects and their associated attributes which are included within the scope of this protocol. Many of these attributes are derived from other relevant documents:

      - Document Printing Application (DPA) [ISO10175]
      - RFC 1759 Printer MIB [RFC1759]

Each attribute is uniquely identified in this document using a "keyword" (see section 12.2.1) which is the name of the attribute. The keyword is included in the section header describing that attribute.

   Note:  Not only are keywords used to identify attributes, but one of
   the attribute syntaxes described below is "keyword" so that some
   attributes have keyword values.  Therefore, these attributes are
   defined as having an attribute syntax that is a set of keywords.

4.1 Attribute Syntaxes

This section defines the basic attribute syntax types that all clients and IPP objects MUST be able to accept in responses and accept in requests, respectively. Each attribute description in sections 3 and 4 includes the name of attribute syntax(es) in the heading (in parentheses). A conforming implementation of an attribute MUST include the semantics of the attribute syntax(es) so identified. Section 6.3 describes how the protocol can be extended with new attribute syntaxes.

The attribute syntaxes are specified in the following sub-sections, where the sub-section heading is the keyword name of the attribute syntax inside the single quotes. In operation requests and responses each attribute value MUST be represented as one of the attribute syntaxes specified in the sub-section heading for the attribute. In addition, the value of an attribute in a response (but not in a

   request) MAY be one of the "out-of-band" values whose special
   encoding rules are defined in the "Encoding and Transport" document
   [RFC2910].   Standard "out-of-band" values are:
   
      'unknown': The attribute is supported by the IPP object, but the
         value is unknown to the IPP object for some reason.
      'unsupported': The attribute is unsupported by the IPP object.
         This value MUST be returned only as the value of an attribute
         in the Unsupported Attributes Group.
      'no-value': The attribute is supported by the Printer object, but
         the administrator has not yet configured a value.

All attributes in a request MUST have one or more values as defined in Sections 4.2 to 4.4. Thus clients MUST NOT supply attributes with "out-of-band" values for operations defined in this document. All attributes in a response MUST have one or more values as defined in Sections 4.2 to 4.4 or a single "out-of-band" value.

Most attributes are defined to have a single attribute syntax. However, a few attributes (e.g., "job-sheet", "media", "job-hold- until") are defined to have several attribute syntaxes, depending on the value. These multiple attribute syntaxes are separated by the "|" character in the sub-section heading to indicate the choice. Since each value MUST be tagged as to its attribute syntax in the protocol, a single-valued attribute instance may have any one of its attribute syntaxes and a multi-valued attribute instance may have a mixture of its defined attribute syntaxes.

4.1.1 'text'

   A text attribute is an attribute whose value is a sequence of zero or
   more characters encoded in a maximum of 1023 ('MAX') octets.  MAX is
   the maximum length for each value of any text attribute.  However, if
   an attribute will always contain values whose maximum length is much
   less than MAX, the definition of that attribute will include a
   qualifier that defines the maximum length for values of that
   attribute.  For example:  the "printer-location" attribute is
   specified as "printer-location (text(127))".  In this case, text
   values for "printer-location" MUST NOT exceed 127 octets; if supplied
   with a longer text string via some external interface (other than the
   protocol), implementations are free to truncate to this shorter
   length limitation.

In this document, all text attributes are defined using the 'text' syntax. However, 'text' is used only for brevity; the formal interpretation of 'text' is: 'textWithoutLanguage | textWithLanguage'. That is, for any attribute defined in this document using the 'text' attribute syntax, all IPP objects and clients MUST support both the 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes. However, in actual usage and protocol execution, objects and clients accept and return only one of the two syntax per attribute. The syntax 'text' never appears "on- the-wire".

Both 'textWithoutLanguage' and 'textWithLanguage' are needed to support the real world needs of interoperability between sites and systems that use different natural languages as the basis for human communication. Generally, one natural language applies to all text attributes in a given request or response. The language is indicated by the "attributes-natural-language" operation attribute defined in section 3.1.4 or "attributes-natural-language" job attribute defined in section 4.3.20, and there is no need to identify the natural language for each text string on a value-by-value basis. In these cases, the attribute syntax 'textWithoutLanguage' is used for text attributes. In other cases, the client needs to supply or the Printer object needs to return a text value in a natural language that is different from the rest of the text values in the request or response. In these cases, the client or Printer object uses the attribute syntax 'textWithLanguage' for text attributes (this is the Natural Language Override mechanism described in section 3.1.4).

The 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes are described in more detail in the following sections.

4.1.1.1 'textWithoutLanguage'

The 'textWithoutLanguage' syntax indicates a value that is sequence of zero or more characters encoded in a maximum of 1023 (MAX) octets. Text strings are encoded using the rules of some charset. The Printer object MUST support the UTF-8 charset [RFC2279] and MAY support additional charsets to represent 'text' values, provided that the charsets are registered with IANA [IANA-CS]. See Section 4.1.7 for the definition of the 'charset' attribute syntax, including restricted semantics and examples of charsets.

4.1.1.2 'textWithLanguage'

The 'textWithLanguage' attribute syntax is a compound attribute syntax consisting of two parts: a 'textWithoutLanguage' part encoded in a maximum of 1023 (MAX) octets plus an additional 'naturalLanguage' (see section 4.1.8) part that overrides the natural language in force. The 'naturalLanguage' part explicitly identifies the natural language that applies to the text part of that value and that value alone. For any give text attribute, the 'textWithoutLanguage' part is limited to the maximum length defined for that 'text' attribute, and the 'naturalLanguage' part is always limited to 63 (additional) octets. Using the 'textWithLanguage' attribute syntax rather than the normal 'textWithoutLanguage' syntax is the so-called Natural Language Override mechanism and MUST be supported by all IPP objects and clients.

If the attribute is multi-valued (1setOf text), then the 'textWithLanguage' attribute syntax MUST be used to explicitly specify each attribute value whose natural language needs to be overridden. Other values in a multi-valued 'text' attribute in a request or a response revert to the natural language of the operation attribute.

In a create request, the Printer object MUST accept and store with the Job object any natural language in the "attributes-natural- language" operation attribute, whether the Printer object supports that natural language or not. Furthermore, the Printer object MUST accept and store any 'textWithLanguage' attribute value, whether the Printer object supports that natural language or not. These requirements are independent of the value of the "ipp-attribute- fidelity" operation attribute that the client MAY supply.

   Example:  If the client supplies the "attributes-natural-language"
   operation attribute with the value: 'en' indicating English, but the
   value of the "job-name" attribute is in French, the client MUST use
   the 'textWithLanguage' attribute syntax with the following two
   values:

'fr': Natural Language Override indicating French 'Rapport Mensuel': the job name in French

See the "Encoding and Transport" document [RFC2910] section 3.9 for the encoding of the two parts and Appendix A for a detailed example of the 'textWithLanguage' attribute syntax.

4.1.2 'name'

This syntax type is used for user-friendly strings, such as a Printer name, that, for humans, are more meaningful than identifiers. Names are never translated from one natural language to another. The 'name' attribute syntax is essentially the same as 'text', including the REQUIRED support of UTF-8 except that the sequence of characters is limited so that its encoded form MUST NOT exceed 255 (MAX) octets.

Also like 'text', 'name' is really an abbreviated notation for either 'nameWithoutLanguage' or 'nameWithLanguage'. That is, all IPP objects and clients MUST support both the 'nameWithoutLanguage' and 'nameWithLanguage' attribute syntaxes. However, in actual usage and protocol execution, objects and clients accept and return only one of the two syntax per attribute. The syntax 'name' never appears "on- the-wire".

Only the 'text' and 'name' attribute syntaxes permit the Natural Language Override mechanism.

Some attributes are defined as 'type3 keyword | name'. These attributes support values that are either type3 keywords or names. This dual-syntax mechanism enables a site administrator to extend these attributes to legally include values that are locally defined by the site administrator. Such names are not registered with IANA.

4.1.2.1 'nameWithoutLanguage'

The 'nameWithoutLanguage' syntax indicates a value that is sequence of zero or more characters encoded in a maximum of 255 (MAX) octets.

4.1.2.2 'nameWithLanguage'

The 'nameWithLanguage' attribute syntax is a compound attribute syntax consisting of two parts: a 'nameWithoutLanguage' part encoded in a maximum of 1023 (MAX) octets plus an additional 'naturalLanguage' (see section 4.1.8) part that overrides the natural language in force. The 'naturalLanguage' part explicitly identifies the natural language that applies to that name value and that name value alone. For any give text attribute, the 'textWithoutLanguage' part is limited to the maximum length defined for that 'text' attribute, and the 'naturalLanguage' part is always limited to 63 (additional) octets. Using the 'textWithLanguage' attribute syntax rather than the normal 'textWithoutLanguage' syntax is the so-called Natural Language Override mechanism and MUST be supported by all IPP objects and clients.

The 'nameWithLanguage' attribute syntax behaves the same as the 'textWithLanguage' syntax. Using the 'textWithLanguage' attribute syntax rather than the normal 'textWithoutLanguage' syntax is the so-called Natural Language Override mechanism and MUST be supported by all IPP objects and clients. If a name is in a language that is different than the rest of the object or operation, then this 'nameWithLanguage' syntax is used rather than the generic 'nameWithoutLanguage' syntax.

If the attribute is multi-valued (1setOf text), then the 'nameWithLanguage' attribute syntax MUST be used to explicitly specify each attribute value whose natural language needs to be overridden.

Other values in a multi-valued 'name' attribute in a request or a response revert to the natural language of the operation attribute.

In a create request, the Printer object MUST accept and store with the Job object any natural language in the "attributes-natural- language" operation attribute, whether the Printer object supports that natural language or not. Furthermore, the Printer object MUST accept and store any 'nameWithLanguage' attribute value, whether the Printer object supports that natural language or not. These requirements are independent of the value of the "ipp-attribute- fidelity" operation attribute that the client MAY supply.

   Example:  If the client supplies the "attributes-natural-language"
   operation attribute with the value:  'en' indicating English, but the
   "printer-name" attribute is in German, the client MUST use the
   'nameWithLanguage' attribute syntax as follows:
   
      'de':  Natural Language Override indicating German
      'Farbdrucker':  the Printer name in German

See the "Encoding and Transport" document [RFC2910] section 3.9 for the encoding of the two parts and Appendix A for a detailed example of the 'nameWithLanguage' attribute syntax.

4.1.2.3 Matching 'name' attribute values

For purposes of matching two 'name' attribute values for equality, such as in job validation (where a client-supplied value for attribute "xxx" is checked to see if the value is among the values of the Printer object's corresponding "xxx-supported" attribute), the following match rules apply:

'keyword' values never match 'name' values.

'name' (nameWithoutLanguage and nameWithLanguage) values match if (1) the name parts match and (2) the Associated Natural- Language parts (see section 3.1.4.1) match. The matching rules are:

a. the name parts match if the two names are identical

            character by character, except it is RECOMMENDED that case
            be ignored.  For example: 'Ajax-letter-head-white' MUST
            match 'Ajax-letter-head-white' and SHOULD match 'ajax-
            letter-head-white' and 'AJAX-LETTER-HEAD-WHITE'.

b. the Associated Natural-Language parts match if the shorter

of the two meets the syntactic requirements of RFC 1766 [RFC1766] and matches byte for byte with the longer. For example, 'en' matches 'en', 'en-us' and 'en-gb', but matches neither 'fr' nor 'e'.

4.1.3 'keyword'

The 'keyword' attribute syntax is a sequence of characters, length: 1 to 255, containing only the US-ASCII [ASCII] encoded values for lowercase letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"), dot ("."), and underscore ("_"). The first character MUST be a lowercase letter. Furthermore, keywords MUST be in U.S. English.

This syntax type is used for enumerating semantic identifiers of entities in the abstract protocol, i.e., entities identified in this document. Keywords are used as attribute names or values of attributes. Unlike 'text' and 'name' attribute values, 'keyword' values MUST NOT use the Natural Language Override mechanism, since they MUST always be US-ASCII and U.S. English.

Keywords are for use in the protocol. A user interface will likely provide a mapping between protocol keywords and displayable user- friendly words and phrases which are localized to the natural language of the user. While the keywords specified in this document MAY be displayed to users whose natural language is U.S. English, they MAY be mapped to other U.S. English words for U.S. English users, since the user interface is outside the scope of this document.

In the definition for each attribute of this syntax type, the full set of defined keyword values for that attribute are listed.

When a keyword is used to represent an attribute (its name), it MUST be unique within the full scope of all IPP objects and attributes. When a keyword is used to represent a value of an attribute, it MUST be unique just within the scope of that attribute. That is, the same keyword MUST NOT be used for two different values within the same attribute to mean two different semantic ideas. However, the same keyword MAY be used across two or more attributes, representing different semantic ideas for each attribute. Section 6.1 describes how the protocol can be extended with new keyword values. Examples of attribute name keywords:

"job-name"
"attributes-charset"

   Note:  This document uses "type1", "type2", and "type3" prefixes to
   the "keyword" basic syntax to indicate different levels of review for
   extensions (see section 6.1).

4.1.4 'enum'

   The 'enum' attribute syntax is an enumerated integer value that is in
   the range from 1 to 2**31 - 1 (MAX).   Each value has an associated
   'keyword' name.  In the definition for each attribute of this syntax
   type, the full set of possible values for that attribute are listed.
   This syntax type is used for attributes for which there are enum
   values assigned by other standards, such as SNMP MIBs.  A number of
   attribute enum values in this document are also used for
   corresponding attributes in other standards [RFC1759].  This syntax
   type is not used for attributes to which the administrator may assign
   values.  Section 6.1 describes how the protocol can be extended with
   new enum values.

Enum values are for use in the protocol. A user interface will provide a mapping between protocol enum values and displayable user- friendly words and phrases which are localized to the natural language of the user. While the enum symbols specified in this document MAY be displayed to users whose natural language is U.S. English, they MAY be mapped to other U.S. English words for U.S. English users, since the user interface is outside the scope of this document.

Note: SNMP MIBs use '2' for 'unknown' which corresponds to the IPP "out-of-band" value 'unknown'. See the description of the "out-of- band" values at the beginning of Section 4.1. Therefore, attributes of type 'enum' start at '3'.

   Note:  This document uses "type1", "type2", and "type3" prefixes to
   the "enum" basic syntax to indicate different levels of review for
   extensions (see section 6.1).

4.1.5 'uri'

The 'uri' attribute syntax is any valid Uniform Resource Identifier or URI [RFC2396]. Most often, URIs are simply Uniform Resource Locators or URLs. The maximum length of URIs used as values of IPP attributes is 1023 octets. Although most other IPP attribute syntax types allow for only lower-cased values, this attribute syntax type conforms to the case-sensitive and case-insensitive rules specified in [RFC2396]. See also [IPP-IIG] for a discussion of case in URIs.

4.1.6 'uriScheme'

The 'uriScheme' attribute syntax is a sequence of characters representing a URI scheme according to RFC 2396 [RFC2396]. Though RFC 2396 requires that the values be case-insensitive, IPP requires all lower case values in IPP attributes to simplify comparing by IPP clients and Printer objects.

Standard values for this syntax type are the following keywords:

      'ipp':  for IPP schemed URIs (e.g., "ipp:...")
      'http':  for HTTP schemed URIs (e.g., "http:...")
      'https':  for use with HTTPS schemed URIs (e.g., "https:...") (not
         on IETF standards track)
      'ftp': for FTP schemed URIs (e.g., "ftp:...")
      'mailto': for SMTP schemed URIs (e.g., "mailto:...")
      'file': for file schemed URIs (e.g., "file:...")

A Printer object MAY support any URI 'scheme' that has been registered with IANA [IANA-MT]. The maximum length of URI 'scheme' values used to represent IPP attribute values is 63 octets.

4.1.7 'charset'

The 'charset' attribute syntax is a standard identifier for a charset. A charset is a coded character set and encoding scheme. Charsets are used for labeling certain document contents and 'text' and 'name' attribute values. The syntax and semantics of this attribute syntax are specified in RFC 2046 [RFC2046] and contained in the IANA character-set Registry [IANA-CS] according to the IANA procedures [RFC2278]. Though RFC 2046 requires that the values be case-insensitive US-ASCII [ASCII], IPP requires all lower case values in IPP attributes to simplify comparing by IPP clients and Printer objects. When a character-set in the IANA registry has more than one name (alias), the name labeled as "(preferred MIME name)", if present, MUST be used.

The maximum length of 'charset' values used to represent IPP attribute values is 63 octets.

Some examples are:

      'utf-8':  ISO 10646 Universal Multiple-Octet Coded Character Set
         (UCS) represented as the UTF-8 [RFC2279] transfer encoding
         scheme in which US-ASCII is a subset charset.
      'us-ascii':  7-bit American Standard Code for Information
         Interchange (ASCII), ANSI X3.4-1986 [ASCII].  That standard
         defines US-ASCII, but RFC 2045 [RFC2045] eliminates most of the
         control characters from conformant usage in MIME and IPP.
      'iso-8859-1':  8-bit One-Byte Coded Character Set, Latin Alphabet
         Nr 1 [ISO8859-1].  That standard defines a coded character set
         that is used by Latin languages in the Western Hemisphere and
         Western Europe.  US-ASCII is a subset charset.

Some attribute descriptions MAY place additional requirements on charset values that may be used, such as REQUIRED values that MUST be supported or additional restrictions, such as requiring that the charset have US- ASCII as a subset charset.

4.1.8 'naturalLanguage'

The 'naturalLanguage' attribute syntax is a standard identifier for a natural language and optionally a country. The values for this syntax type are defined by RFC 1766 [RFC1766]. Though RFC 1766 requires that the values be case-insensitive US-ASCII [ASCII], IPP requires all lower case to simplify comparing by IPP clients and Printer objects. Examples include:

      'en':  for English
      'en-us': for US English
      'fr': for French
      'de':  for German

The maximum length of 'naturalLanguage' values used to represent IPP attribute values is 63 octets.

4.1.9 'mimeMediaType'

The 'mimeMediaType' attribute syntax is the Internet Media Type (sometimes called MIME type) as defined by RFC 2046 [RFC2046] and registered according to the procedures of RFC 2048 [RFC2048] for identifying a document format. The value MAY include a charset, or other, parameter, depending on the specification of the Media Type in the IANA Registry [IANA-MT]. Although most other IPP syntax types allow for only lower-cased values, this syntax type allows for mixed-case values which are case-insensitive.

Examples are:

      'text/html': An HTML document
      'text/plain': A plain text document in US-ASCII (RFC 2046
         indicates that in the absence of the charset parameter MUST
         mean US-ASCII rather than simply unspecified) [RFC2046].
      'text/plain; charset=US-ASCII':  A plain text document in US-ASCII
         [52, 56].
      'text/plain; charset=ISO-8859-1':  A plain text document in ISO
         8859-1 (Latin 1) [ISO8859-1].
      'text/plain; charset=utf-8':  A plain text document in ISO 10646
         represented as UTF-8 [RFC2279]
      'application/postscript':  A PostScript document [RFC2046]
      'application/vnd.hp-PCL':  A PCL document [IANA-MT] (charset
         escape sequence embedded in the document data)
      'application/pdf':  Portable Document Format - see IANA MIME Media
         Type registry
      'application/octet-stream': Auto-sense - see section 4.1.9.1

The maximum length of a 'mimeMediaType' value to represent IPP attribute values is 255 octets.

4.1.9.1 Application/octet-stream -- Auto-Sensing the document format

One special type is 'application/octet-stream'. If the Printer object supports this value, the Printer object MUST be capable of auto-sensing the format of the document data using an implementation-dependent method that examines some number of octets of the document data, either as part of the create operation and/or at document processing time. During auto-sensing, a Printer may determine that the document-data has a format that the Printer doesn't recognize. If the Printer determines this problem before returning an operation response, it rejects the request and returns the 'client-error-document-format-not-supported' status code. If the Printer determines this problem after accepting the request and returning an operation response with one of the successful status codes, the Printer adds the 'unsupported-document-format' value to the job's "job-state-reasons" attribute.

If the Printer object's default value attribute "document-format- default" is set to 'application/octet-stream', the Printer object not only supports auto-sensing of the document format, but will depend on the result of applying its auto-sensing when the client does not supply the "document-format" attribute. If the client supplies a document format value, the Printer MUST rely on the supplied attribute, rather than trust its auto-sensing algorithm. To summarize:

      1. If the client does not supply a document format value, the
         Printer MUST rely on its default value setting (which may be
         'application/octet-stream' indicating an auto-sensing
         mechanism).
      2. If the client supplies a value other than 'application/octet-
         stream', the client is supplying valid information about the
         format of the document data and the Printer object MUST trust
         the client supplied value more than the outcome of applying an
         automatic format detection mechanism.  For example, the client
         may be requesting the printing of a PostScript file as a
         'text/plain' document.  The Printer object MUST print a text
         representation of the PostScript commands rather than interpret
         the stream of PostScript commands and print the result.
      3. If the client supplies a value of 'application/octet-stream',
         the client is indicating that the Printer object MUST use its
         auto-sensing mechanism on the client supplied document data
         whether auto-sensing is the Printer object's default or not.
   
   Note:  Since the auto-sensing algorithm is probabilistic, if the
   client requests both auto-sensing ("document-format" set to
   'application/octet-stream') and true fidelity ("ipp-attribute-
   fidelity" set to 'true'), the Printer object might not be able to
   guarantee exactly what the end user intended (the auto-sensing
   algorithm might mistake one document format for another), but it is
   able to guarantee that its auto-sensing mechanism be used.

When a Printer performs auto-sensing of a document in a submitted job, it is RECOMMENDED that the Printer indicate to the user that such auto-sensing has occurred and which document-format was auto- sensed by printing that information on the job's job-start-sheet.

4.1.10 'octetString'

The 'octetString' attribute syntax is a sequence of octets encoded in a maximum of 1023 octets which is indicated in sub-section headers using the notation: octetString(MAX). This syntax type is used for opaque data.

4.1.11 'boolean'

   The 'boolean' attribute syntax has only two values:  'true' and
   'false'.

4.1.12 'integer'

   The 'integer' attribute syntax is an integer value that is in the
   range from -2**31 (MIN) to 2**31 - 1 (MAX).  Each individual
   attribute may specify the range constraint explicitly in sub-section
   headers if the range is different from the full range of possible
   integer values.  For example:  job-priority (integer(1:100)) for the
   "job-priority" attribute.  However, the enforcement of that
   additional constraint is up to the IPP objects, not the protocol.

4.1.13 'rangeOfInteger'

The 'rangeOfInteger' attribute syntax is an ordered pair of integers that defines an inclusive range of integer values. The first integer specifies the lower bound and the second specifies the upper bound. If a range constraint is specified in the header description for an attribute in this document whose attribute syntax is 'rangeOfInteger' (i.e., 'X:Y' indicating X as a minimum value and Y as a maximum value), then the constraint applies to both integers.

4.1.14 'dateTime'

The 'dateTime' attribute syntax is a standard, fixed length, 11 octet representation of the "DateAndTime" syntax as defined in RFC 2579 [RFC2579]. RFC 2579 also identifies an 8 octet representation of a "DateAndTime" value, but IPP objects MUST use the 11 octet representation. A user interface will provide a mapping between protocol dateTime values and displayable user-friendly words or presentation values and phrases which are localized to the natural language and date format of the user, including time zone.

4.1.15 'resolution'

   The 'resolution' attribute syntax specifies a two-dimensional
   resolution in the indicated units.  It consists of 3 values: a cross
   feed direction resolution (positive integer value), a feed direction
   resolution (positive integer value), and a units value.  The
   semantics of these three components are taken from the Printer MIB
   [RFC1759] suggested values.  That is, the cross feed direction
   component resolution component is the same as the
   prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed
   direction component resolution component is the same as the
   prtMarkerAddressabilityFeedDir in the Printer MIB, and the units
   component is the same as the prtMarkerAddressabilityUnit object in
   the Printer MIB (namely, '3' indicates dots per inch and '4'
   indicates dots per centimeter).  All three values MUST be present
   even if the first two values are the same.  Example:  '300', '600',
   '3' indicates a 300 dpi cross-feed direction resolution, a 600 dpi
   feed direction resolution, since a '3' indicates dots per inch (dpi).

4.1.16 '1setOf X'

   The '1setOf  X' attribute syntax is 1 or more values of attribute
   syntax type X.  This syntax type is used for multi-valued attributes.
   The syntax type is called '1setOf' rather than just 'setOf' as a
   reminder that the set of values MUST NOT be empty (i.e., a set of

size 0). Sets are normally unordered. However each attribute description of this type may specify that the values MUST be in a certain order for that attribute.

4.2 Job Template Attributes

Job Template attributes describe job processing behavior. Support for Job Template attributes by a Printer object is OPTIONAL (see section 12.2.3 for a description of support for OPTIONAL attributes). Also, clients OPTIONALLY supply Job Template attributes in create requests.

Job Template attributes conform to the following rules. For each Job Template attribute called "xxx":

If the Printer object supports "xxx" then it MUST support both a "xxx-default" attribute (unless there is a "No" in the table below) and a "xxx-supported" attribute. If the Printer object doesn't support "xxx", then it MUST support neither an "xxx- default" attribute nor an "xxx-supported" attribute, and it MUST treat an attribute "xxx" supplied by a client as unsupported. An attribute "xxx" may be supported for some document formats and not supported for other document formats. For example, it is expected that a Printer object would only support "orientation-requested" for some document formats (such as 'text/plain' or 'text/html') but not others (such as 'application/postscript').

"xxx" is OPTIONALLY supplied by the client in a create request. If "xxx" is supplied, the client is indicating a desired job processing behavior for this Job. When "xxx" is not supplied, the client is indicating that the Printer object apply its default job processing behavior at job processing time if the document content does not contain an embedded instruction indicating an xxx-related behavior.

Since an administrator MAY change the default value attribute after a Job object has been submitted but before it has been processed, the default value used by the Printer object at job processing time may be different that the default value in effect at job submission time.

The "xxx-supported" attribute is a Printer object attribute that describes which job processing behaviors are supported by that Printer object. A client can query the Printer object to find out what xxx-related behaviors are supported by inspecting the returned values of the "xxx-supported" attribute.

Note: The "xxx" in each "xxx-supported" attribute name is singular, even though an "xxx-supported" attribute usually has more than one value, such as "job-sheet-supported", unless the "xxx" Job Template attribute is plural, such as "finishings" or "sides". In such cases the "xxx-supported" attribute names are: "finishings- supported" and "sides-supported".

The "xxx-default" default value attribute describes what will be done at job processing time when no other job processing information is supplied by the client (either explicitly as an IPP attribute in the create request or implicitly as an embedded instruction within the document data).

If an application wishes to present an end user with a list of supported values from which to choose, the application SHOULD query the Printer object for its supported value attributes. The application SHOULD also query the default value attributes. If the application then limits selectable values to only those value that are supported, the application can guarantee that the values supplied by the client in the create request all fall within the set of supported values at the Printer. When querying the Printer, the client MAY enumerate each attribute by name in the Get-Printer- Attributes Request, or the client MAY just name the "job-template" group in order to get the complete set of supported attributes (both supported and default attributes).

The "finishings" attribute is an example of a Job Template attribute. It can take on a set of values such as 'staple', 'punch', and/or 'cover'. A client can query the Printer object for the "finishings- supported" attribute and the "finishings-default" attribute. The supported attribute contains a set of supported values. The default value attribute contains the finishing value(s) that will be used for a new Job if the client does not supply a "finishings" attribute in the create request and the document data does not contain any corresponding finishing instructions. If the client does supply the "finishings" attribute in the create request, the IPP object validates the value or values to make sure that they are a subset of the supported values identified in the Printer object's "finishings- supported" attribute. See section 3.1.7.

   The table below summarizes the names and relationships for all Job
   Template attributes. The first column of the table (labeled "Job
   Attribute") shows the name and syntax for each Job Template attribute
   in the Job object. These are the attributes that can optionally be
   supplied by the client in a create request.   The last two columns
   (labeled "Printer: Default Value Attribute" and "Printer: Supported
   Values Attribute") show the name and syntax for each Job Template
   attribute in the Printer object (the default value attribute and the

supported values attribute). A "No" in the table means the Printer MUST NOT support the attribute (that is, the attribute is simply not applicable). For brevity in the table, the 'text' and 'name' entries do not show the maximum length for each attribute.

     +===================+======================+======================+
     | Job Attribute     |Printer: Default Value|  Printer: Supported  |
     |                   |   Attribute          |   Values Attribute   |
     +===================+======================+======================+
     | job-priority      | job-priority-default |job-priority-supported|
     | (integer 1:100)   | (integer 1:100)      |(integer 1:100)       |
     +-------------------+----------------------+----------------------+
     | job-hold-until    | job-hold-until-      |job-hold-until-       |
     | (type3 keyword |  |  default             | supported            |
     |    name)          |  (type3 keyword |    |(1setOf (             |
     |                   |    name)             |type3 keyword | name))|
     +-------------------+----------------------+----------------------+
     | job-sheets        | job-sheets-default   |job-sheets-supported  |
     | (type3 keyword |  | (type3 keyword |     |(1setOf (             |
     |    name)          |    name)             |type3 keyword | name))|
     +-------------------+----------------------+----------------------+
     |multiple-document- |multiple-document-    |multiple-document-    |
     | handling          | handling-default     |handling-supported    |
     | (type2 keyword)   | (type2 keyword)      |(1setOf type2 keyword)|
     +-------------------+----------------------+----------------------+
     | copies            | copies-default       | copies-supported     |
     | (integer (1:MAX)) | (integer (1:MAX))    | (rangeOfInteger      |
     |                   |                      |       (1:MAX))       |
     +-------------------+----------------------+----------------------+
     | finishings        | finishings-default   | finishings-supported |
     |(1setOf type2 enum)|(1setOf type2 enum)   |(1setOf type2 enum)   |
     +-------------------+----------------------+----------------------+
     | page-ranges       | No                   | page-ranges-         |
     | (1setOf           |                      | supported (boolean)  |
     |   rangeOfInteger  |                      |                      |
     |        (1:MAX))   |                      |                      |
     +-------------------+----------------------+----------------------+
     | sides             | sides-default        | sides-supported      |
     | (type2 keyword)   | (type2 keyword)      |(1setOf type2 keyword)|
     +-------------------+----------------------+----------------------+
     | number-up         | number-up-default    | number-up-supported  |
     | (integer (1:MAX)) | (integer (1:MAX))    |(1setOf (integer      |
     |                   |                      | (1:MAX) |            |
     |                   |                      |  rangeOfInteger      |
     |                   |                      |   (1:MAX)))          |
     +-------------------+----------------------+----------------------+
     | orientation-      |orientation-requested-|orientation-requested-|
     |  requested        |  default             |  supported           |
     |   (type2 enum)    |  (type2 enum)        |  (1setOf type2 enum) |
     +-------------------+----------------------+----------------------+
     | media             | media-default        | media-supported      |
     | (type3 keyword |  | (type3 keyword |     |(1setOf (             |
     |    name)          |    name)             |type3 keyword | name))|
     |                   |                      |                      |
     |                   |                      | media-ready          |
     |                   |                      |(1setOf (             |
     |                   |                      |type3 keyword | name))|
     +-------------------+----------------------+----------------------+
     | printer-resolution| printer-resolution-  | printer-resolution-  |
     | (resolution)      |  default             | supported            |
     |                   | (resolution)         |(1setOf resolution)   |
     +-------------------+----------------------+----------------------+
     | print-quality     | print-quality-default| print-quality-       |
     | (type2 enum)      | (type2 enum)         | supported            |
     |                   |                      |(1setOf type2 enum)   |
     +-------------------+----------------------+----------------------+

4.2.1 job-priority (integer(1:100))

This attribute specifies a priority for scheduling the Job. A higher value specifies a higher priority. The value 1 indicates the lowest possible priority. The value 100 indicates the highest possible priority. Among those jobs that are ready to print, a Printer MUST print all jobs with a priority value of n before printing those with a priority value of n-1 for all n.

If the Printer object supports this attribute, it MUST always support the full range from 1 to 100. No administrative restrictions are permitted. This way an end-user can always make full use of the entire range with any Printer object. If privileged jobs are implemented outside IPP/1.1, they MUST have priorities higher than 100, rather than restricting the range available to end-users.

If the client does not supply this attribute and this attribute is supported by the Printer object, the Printer object MUST use the value of the Printer object's "job-priority-default" at job submission time (unlike most Job Template attributes that are used if necessary at job processing time).

The syntax for the "job-priority-supported" is also integer(1:100). This single integer value indicates the number of priority levels supported. The Printer object MUST take the value supplied by the client and map it to the closest integer in a sequence of n integers values that are evenly distributed over the range from 1 to 100 using the formula:

      roundToNearestInt((100x+50)/n)

where n is the value of "job-priority-supported" and x ranges from 0 through n-1.

   For example, if n=1 the sequence of values is 50;  if n=2, the
   sequence of values is:  25 and 75;  if n = 3, the sequence of values
   is:  17, 50 and 83;  if n = 10, the sequence of values is: 5, 15, 25,
   35, 45, 55, 65, 75, 85, and 95;  if n = 100, the sequence of values
   is:  1, 2, 3, ... 100.

If the value of the Printer object's "job-priority-supported" is 10 and the client supplies values in the range 1 to 10, the Printer object maps them to 5, in the range 11 to 20, the Printer object maps them to 15, etc.

4.2.2 job-hold-until (type3 keyword | name (MAX))

This attribute specifies the named time period during which the Job MUST become a candidate for printing.

Standard keyword values for named time periods are:

      'no-hold': immediately, if there are not other reasons to hold the
         job
      'indefinite':  - the job is held indefinitely, until a client
         performs a Release-Job (section 3.3.6)
      'day-time': during the day
      'evening': evening
      'night': night
      'weekend': weekend
      'second-shift': second-shift (after close of business)
      'third-shift': third-shift (after midnight)

An administrator MUST associate allowable print times with a named time period (by means outside the scope of this IPP/1.1 document). An administrator is encouraged to pick names that suggest the type of time period. An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation.

If the value of this attribute specifies a time period that is in the future, the Printer SHOULD add the 'job-hold-until-specified' value to the job's "job-state-reasons" attribute, MUST move the job to the

'pending-held' state, and MUST NOT schedule the job for printing until the specified time-period arrives.

When the specified time period arrives, the Printer MUST remove the 'job-hold-until-specified' value from the job's "job-state-reason" attribute, if present. If there are no other job state reasons that keep the job in the 'pending-held' state, the Printer MUST consider the job as a candidate for processing by moving the job to the 'pending' state.

If this job attribute value is the named value 'no-hold', or the specified time period has already started, the job MUST be a candidate for processing immediately.

If the client does not supply this attribute and this attribute is supported by the Printer object, the Printer object MUST use the value of the Printer object's "job-hold-until-default" at job submission time (unlike most Job Template attributes that are used if necessary at job processing time).

4.2.3 job-sheets (type3 keyword | name(MAX))

This attribute determines which job start/end sheet(s), if any, MUST be printed with a job.

Standard keyword values are:

'none': no job sheet is printed
'standard': one or more site specific standard job sheets are

printed, e.g. a single start sheet or both start and end sheet is printed

An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation.

The effect of this attribute on jobs with multiple documents MAY be affected by the "multiple-document-handling" job attribute (section 4.2.4), depending on the job sheet semantics.

4.2.4 multiple-document-handling (type2 keyword)

This attribute is relevant only if a job consists of two or more documents. This attribute MUST be supported with at least one value if the Printer supports multiple documents per job (see sections 3.2.4 and 3.3.1). The attribute controls finishing operations and the placement of one or more print-stream pages into impressions and onto media sheets. When the value of the "copies" attribute exceeds 1, it also controls the order in which the copies that result from processing the documents are produced. For the purposes of this explanations, if "a" represents an instance of document data, then the result of processing the data in document "a" is a sequence of media sheets represented by "a(*)".

Standard keyword values are:

      'single-document': If a Job object has multiple documents, say,
         the document data is called a and b, then the result of
         processing all the document data (a and then b) MUST be treated
         as a single sequence of media sheets for finishing operations;
         that is, finishing would be performed on the concatenation of
         the sequences a(*),b(*).  The Printer object MUST NOT force the
         data in each document instance to be formatted onto a new
         print-stream page, nor to start a new impression on a new media
         sheet. If more than one copy is made, the ordering of the sets
         of media sheets resulting from processing the document data
         MUST be a(*), b(*), a(*), b(*), start on a new media sheet.
      'separate-documents-uncollated-copies': If a Job object has
         multiple documents, say, the document data is called a and b,
         then the result of processing the data in each document
         instance MUST be treated as a single sequence of media sheets
         for finishing operations; that is, the sets a(*) and b(*) would
         each be finished separately. The Printer object MUST force each
         copy of the result of processing the data in a single document
         to start on a new media sheet. If more than one copy is made,
         the ordering of the sets of media sheets resulting from
         processing the document data MUST be a(*), a(*), ..., b(*),
         b(*) ... .
      'separate-documents-collated-copies': If a Job object has multiple
         documents, say, the document data is called a and b, then the
         result of processing the data in each document instance MUST be
         treated as a single sequence of media sheets for finishing
         operations; that is, the sets a(*) and b(*) would each be
         finished separately. The Printer object MUST force each copy of
         the result of processing the data in a single document to start
         on a new media sheet.  If more than one copy is made, the
         ordering of the sets of media sheets resulting from processing
         the document data MUST be a(*), b(*), a(*), b(*), ... .
      'single-document-new-sheet':  Same as 'single-document', except
         that the Printer object MUST ensure that the first impression
         of each document instance in the job is placed on a new media
         sheet.  This value allows multiple documents to be stapled
         together with a single staple where each document starts on a
         new sheet.

The 'single-document' value is the same as 'separate-documents- collated-copies' with respect to ordering of print-stream pages, but not media sheet generation, since 'single-document' will put the first page of the next document on the back side of a sheet if an odd number of pages have been produced so far for the job, while 'separate-documents-collated- copies' always forces the next document or document copy on to a new sheet. In addition, if the "finishings" attribute specifies 'staple', then with 'single-document', documents a and b are stapled together as a single document with no regard to new sheets, with 'single-document-new-sheet', documents a and b are stapled together as a single document, but document b starts on a new sheet, but with 'separate-documents-uncollated-copies' and 'separate-documents-collated-copies', documents a and b are stapled separately.

Note: None of these values provide means to produce uncollated sheets within a document, i.e., where multiple copies of sheet n are produced before sheet n+1 of the same document.

The relationship of this attribute and the other attributes that control document processing is described in section 15.3.

4.2.5 copies (integer(1:MAX))

This attribute specifies the number of copies to be printed.

On many devices the supported number of collated copies will be limited by the number of physical output bins on the device, and may be different from the number of uncollated copies which can be supported.

Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4) and the relationship of this attribute and the other attributes that control document processing is described in section 15.3.

4.2.6 finishings (1setOf type2 enum)

This attribute identifies the finishing operations that the Printer uses for each copy of each printed document in the Job. For Jobs with multiple documents, the "multiple-document-handling" attribute determines what constitutes a "copy" for purposes of finishing.

Standard enum values are:

   Value  Symbolic Name and Description
   
   '3'    'none':  Perform no finishing
   '4'    'staple':  Bind the document(s) with one or more staples. The
             exact number and placement of the staples is site-
             defined.
   '5'    'punch':  This value indicates that holes are required in the
             finished document. The exact number and placement of the
             holes is site-defined  The punch specification MAY be
             satisfied (in a site- and implementation-specific manner)
             either by drilling/punching, or by substituting pre-
             drilled media.
   '6'    'cover':  This value is specified when it is desired to select
             a non-printed (or pre-printed) cover for the document.
             This does not supplant the specification of a printed
             cover (on cover stock medium) by the document itself.
   '7'    'bind':  This value indicates that a binding is to be applied
             to the document; the type and placement of the binding is
             site-defined.
   '8'    'saddle-stitch':  Bind the document(s) with one or more
             staples (wire stitches) along the middle fold.  The exact
             number and placement of the staples and the middle fold
             is implementation and/or site-defined.
   '9'    'edge-stitch':  Bind the document(s) with one or more staples
             (wire stitches) along one edge.  The exact number and
             placement of the staples is implementation and/or site-
             defined.
   '10'-'19'   reserved for future generic finishing enum values.

The following values are more specific; they indicate a corner or an edge as if the document were a portrait document (see below):

   '20'   'staple-top-left':  Bind the document(s) with one or more
             staples in the top left corner.
   '21'   'staple-bottom-left':  Bind the document(s) with one or more
             staples in the bottom left corner.
   '22'   'staple-top-right':  Bind the document(s) with one or more
             staples in the top right corner.
   '23'   'staple-bottom-right':  Bind the document(s) with one or more
             staples in the bottom right corner.
   '24'   'edge-stitch-left':  Bind the document(s) with one or more
             staples (wire stitches) along the left edge.  The exact
             number and placement of the staples is implementation
             and/or site-defined.
   '25'   'edge-stitch-top':  Bind the document(s) with one or more
             staples (wire stitches) along the top edge.  The exact
             number and placement of the staples is implementation
             and/or site-defined.
   '26'   'edge-stitch-right':  Bind the document(s) with one or more
             staples (wire stitches) along the right edge.  The exact
             number and placement of the staples is implementation
             and/or site-defined.
   '27'   'edge-stitch-bottom':  Bind the document(s) with one or more
             staples (wire stitches) along the bottom edge.  The exact
             number and placement of the staples is implementation
             and/or site-defined.
   '28'   'staple-dual-left':  Bind the document(s) with two staples
             (wire stitches) along the left edge assuming a portrait
             document (see above).
   '29'   'staple-dual-top':  Bind the document(s) with two staples
             (wire stitches) along the top edge assuming a portrait
             document (see above).
   '30'   'staple-dual-right':  Bind the document(s) with two staples
             (wire stitches) along the right edge assuming a portrait
             document (see above).
   '31'   'staple-dual-bottom':  Bind the document(s) with two staples
             (wire stitches) along the bottom edge assuming a portrait
             document (see above).

The 'staple-xxx' values are specified with respect to the document as if the document were a portrait document. If the document is actually a landscape or a reverse-landscape document, the client supplies the appropriate transformed value. For example, to position a staple in the upper left hand corner of a landscape document when held for reading, the client supplies the 'staple-bottom-left' value (since landscape is defined as a +90 degree rotation of the image with respect to the media from portrait, i.e., anti-clockwise). On the other hand, to position a staple in the upper left hand corner of a reverse-landscape document when held for reading, the client supplies the 'staple-top-right' value (since reverse-landscape is defined as a -90 degree rotation of the image with respect to the media from portrait, i.e., clockwise).

The angle (vertical, horizontal, angled) of each staple with respect to the document depends on the implementation which may in turn depend on the value of the attribute.

If the client supplies a value of 'none' along with any other combination of values, it is the same as if only that other combination of values had been supplied (that is the 'none' value has no effect).

4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX))

This attribute identifies the range(s) of print-stream pages that the Printer object uses for each copy of each document which are to be printed. Nothing is printed for any pages identified that do not exist in the document(s). Ranges MUST be in ascending order, for example: 1-3, 5-7, 15-19 and MUST NOT overlap, so that a non-spooling Printer object can process the job in a single pass. If the ranges are not ascending or are overlapping, the IPP object MUST reject the request and return the 'client-error-bad-request' status code. The attribute is associated with print-stream pages not application- numbered pages (for example, the page numbers found in the headers and or footers for certain word processing applications).

For Jobs with multiple documents, the "multiple-document-handling" attribute determines what constitutes a "copy" for purposes of the specified page range(s). When "multiple-document-handling" is 'single-document', the Printer object MUST apply each supplied page range once to the concatenation of the print-stream pages. For example, if there are 8 documents of 10 pages each, the page-range '41:60' prints the pages in the 5th and 6th documents as a single document and none of the pages of the other documents are printed. When "multiple-document- handling" is 'separate-documents- uncollated-copies' or 'separate-documents-collated-copies', the Printer object MUST apply each supplied page range repeatedly to each document copy. For the same job, the page-range '1:3, 10:10' would print the first 3 pages and the 10th page of each of the 8 documents in the Job, as 8 separate documents.

In most cases, the exact pages to be printed will be generated by a device driver and this attribute would not be required. However, when printing an archived document which has already been formatted, the end user may elect to print just a subset of the pages contained in the document. In this case, if page-range = n.m is specified, the first page to be printed will be page n. All subsequent pages of the document will be printed through and including page m.

"page-ranges-supported" is a boolean value indicating whether or not the printer is capable of supporting the printing of page ranges. This capability may differ from one PDL to another. There is no "page-ranges-default" attribute. If the "page-ranges" attribute is not supplied by the client, all pages of the document will be printed.

4.2.8 sides (type2 keyword)

This attribute specifies how print-stream pages are to be imposed upon the sides of an instance of a selected medium, i.e., an impression.

The standard keyword values are:

      'one-sided': imposes each consecutive print-stream page upon the
         same side of consecutive media sheets.
      'two-sided-long-edge': imposes each consecutive pair of print-
         stream pages upon front and back sides of consecutive media
         sheets, such that the orientation of each pair of print-stream
         pages on the medium would be correct for the reader as if for
         binding on the long edge.  This imposition is sometimes called
         'duplex' or 'head-to-head'.
      'two-sided-short-edge': imposes each consecutive pair of print-
         stream pages upon front and back sides of consecutive media
         sheets, such that the orientation of each pair of print-stream
         pages on the medium would be correct for the reader as if for
         binding on the short edge.  This imposition is sometimes called
         'tumble' or 'head-to-toe'.
      'two-sided-long-edge', 'two-sided-short-edge',
         'tumble', and 'duplex' all work the same for portrait or
         landscape.  However
         'head-to-toe' is
      'tumble' in portrait but 'duplex' in landscape.  'head-to-head'
         also switches between 'duplex' and 'tumble' when using portrait
         and landscape modes.

4.2.9 number-up (integer(1:MAX))

This attribute specifies the number of print-stream pages to impose upon a single side of an instance of a selected medium. For example, if the value is:

   Value  Description
   
   '1'    the Printer MUST place one print-stream page on a single side
             of an instance of the selected medium (MAY add some sort
             of translation, scaling, or rotation).
   '2'    the Printer MUST place two print-stream pages on a single side
             of an instance of the selected medium (MAY add some sort
             of translation, scaling, or rotation).
   '4'    the Printer MUST place four print-stream pages on a single
             side of an instance of the selected medium (MAY add some
             sort of translation, scaling, or rotation).

This attribute primarily controls the translation, scaling and rotation of print-stream pages.

4.2.10 orientation-requested (type2 enum)

This attribute indicates the desired orientation for printed print- stream pages; it does not describe the orientation of the client- supplied print-stream pages.

For some document formats (such as 'application/postscript'), the desired orientation of the print-stream pages is specified within the document data. This information is generated by a device driver prior to the submission of the print job. Other document formats (such as 'text/plain') do not include the notion of desired orientation within the document data. In the latter case it is possible for the Printer object to bind the desired orientation to the document data after it has been submitted. It is expected that a Printer object would only support "orientations-requested" for some document formats (e.g., 'text/plain' or 'text/html') but not others (e.g., 'application/postscript'). This is no different than any other Job Template attribute since section 4.2, item 1, points out that a Printer object may support or not support any Job Template attribute based on the document format supplied by the client. However, a special mention is made here since it is very likely that a Printer object will support "orientation-requested" for only a subset of the supported document formats.

Standard enum values are:

   Value  Symbolic Name and Description
   
   '3'    'portrait':  The content will be imaged across the short edge
             of the medium.
   '4'    'landscape':  The content will be imaged across the long edge
             of the medium.  Landscape is defined to be a rotation of
             the print-stream page to be imaged by +90 degrees with
             respect to the medium (i.e. anti-clockwise) from the
             portrait orientation.  Note:  The +90 direction was
             chosen because simple finishing on the long edge is the
             same edge whether portrait or landscape
   '5'    'reverse-landscape':  The content will be imaged across the
             long edge of the medium.  Reverse-landscape is defined to
             be a rotation of the print-stream page to be imaged by -
             90 degrees with respect to the medium (i.e. clockwise)
             from the portrait orientation.  Note: The 'reverse-
             landscape' value was added because some applications
             rotate landscape -90 degrees from portrait, rather than
             +90 degrees.
   '6'    'reverse-portrait':  The content will be imaged across the
             short edge of the medium.  Reverse-portrait is defined to
             be a rotation of the print-stream page to be imaged by
             180 degrees with respect to the medium from the portrait
             orientation.  Note: The 'reverse-portrait' value was
             added for use with the "finishings" attribute in cases
             where the opposite edge is desired for finishing a
             portrait document on simple finishing devices that have
             only one finishing position.  Thus a 'text'/plain'
             portrait document can be stapled "on the right" by a
             simple finishing device as is common use with some middle
             eastern languages such as Hebrew.

4.2.11 media (type3 keyword | name(MAX))

This attribute identifies the medium that the Printer uses for all impressions of the Job.

The values for "media" include medium-names, medium-sizes, input- trays and electronic forms so that one attribute specifies the media. If a Printer object supports a medium name as a value of this attribute, such a medium name implicitly selects an input-tray that contains the specified medium. If a Printer object supports a medium size as a value of this attribute, such a medium size implicitly selects a medium name that in turn implicitly selects an input-tray that contains the medium with the specified size. If a Printer object supports an input-tray as the value of this attribute, such an input-tray implicitly selects the medium that is in that input-tray at the time the job prints. This case includes manual-feed input- trays. If a Printer object supports an electronic form as the value of this attribute, such an electronic form implicitly selects a medium-name that in turn implicitly selects an input-tray that contains the medium specified by the electronic form. The electronic form also implicitly selects an image that the Printer MUST merge with the document data as its prints each page.

Standard keyword values are taken from ISO DPA [ISO10175], the Printer MIB [RFC1759], and ASME-Y14.1M [ASME-Y14.1M] and are listed in section 14. An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation.

There is also an additional Printer attribute named "media-ready" which differs from "media-supported" in that legal values only include the subset of "media-supported" values that are physically loaded and ready for printing with no operator intervention required. If an IPP object supports "media-supported", it NEED NOT support "media-ready".

The relationship of this attribute and the other attributes that control document processing is described in section 15.3.

4.2.12 printer-resolution (resolution)

This attribute identifies the resolution that Printer uses for the Job.

4.2.13 print-quality (type2 enum)

This attribute specifies the print quality that the Printer uses for the Job.

The standard enum values are:

   Value  Symbolic Name and Description
   
   '3'    'draft': lowest quality available on the printer
   '4'    'normal': normal or intermediate quality on the printer
   '5'    'high': highest quality available on the printer

4.3 Job Description Attributes

The attributes in this section form the attribute group called "job- description". The following table summarizes these attributes. The third column indicates whether the attribute is a REQUIRED attribute that MUST be supported by Printer objects. If it is not indicated as REQUIRED, then it is OPTIONAL. The maximum size in octets for 'text' and 'name' attributes is indicated in parenthesizes.

   +----------------------------+----------------------+--------------+
   |      Attribute             |     Syntax           |   REQUIRED?  |
   +----------------------------+----------------------+--------------+
   | job-uri                    | uri                  |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-id                     | integer(1:MAX)       |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-printer-uri            | uri                  |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-more-info              | uri                  |              |
   +----------------------------+----------------------+--------------+
   | job-name                   | name (MAX)           |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-originating-user-name  | name (MAX)           |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-state                  | type1 enum           |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-state-reasons          | 1setOf type2 keyword |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-state-message          | text (MAX)           |              |
   +----------------------------+----------------------+--------------+
   | job-detailed-status-       | 1setOf text (MAX)    |              |
   |       messages             |                      |              |
   +----------------------------+----------------------+--------------+
   | job-document-access-errors | 1setOf text (MAX)    |              |
   +----------------------------+----------------------+--------------+
   | number-of-documents        | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | output-device-assigned     | name (127)           |              |
   +----------------------------+----------------------+--------------+
   | time-at-creation           | integer (MIN:MAX)    |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | time-at-processing         | integer (MIN:MAX)    |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | time-at-completed          | integer (MIN:MAX)    |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | job-printer-up-time        | integer (1:MAX)      |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | date-time-at-creation      | dateTime             |              |
   +----------------------------+----------------------+--------------+
   | date-time-at-processing    | dateTime             |              |
   +----------------------------+----------------------+--------------+
   | date-time-at-completed     | dateTime             |              |
   +----------------------------+----------------------+--------------+
   | number-of-intervening-jobs | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-message-from-operator  | text (127)           |              |
   +----------------------------+----------------------+--------------+
   | job-k-octets               | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-impressions            | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-media-sheets           | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-k-octets-processed     | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-impressions-completed  | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | job-media-sheets-completed | integer (0:MAX)      |              |
   +----------------------------+----------------------+--------------+
   | attributes-charset         | charset              |  REQUIRED    |
   +----------------------------+----------------------+--------------+
   | attributes-natural-language| naturalLanguage      |  REQUIRED    |
   +----------------------------+----------------------+--------------+

4.3.1 job-uri (uri)

This REQUIRED attribute contains the URI for the job. The Printer object, on receipt of a new job, generates a URI which identifies the new Job. The Printer object returns the value of the "job-uri" attribute as part of the response to a create request. The precise format of a Job URI is implementation dependent. If the Printer object supports more than one URI and there is some relationship between the newly formed Job URI and the Printer object's URI, the Printer object uses the Printer URI supplied by the client in the create request. For example, if the create request comes in over a secure channel, the new Job URI MUST use the same secure channel. This can be guaranteed because the Printer object is responsible for generating the Job URI and the Printer object is aware of its security configuration and policy as well as the Printer URI used in the create request.

For a description of this attribute and its relationship to "job-id" and "job-printer-uri" attribute, see the discussion in section 2.4 on "Object Identity".

4.3.2 job-id (integer(1:MAX))

This REQUIRED attribute contains the ID of the job. The Printer, on receipt of a new job, generates an ID which identifies the new Job on that Printer. The Printer returns the value of the "job-id" attribute as part of the response to a create request. The 0 value is not included to allow for compatibility with SNMP index values which also cannot be 0.

For a description of this attribute and its relationship to "job-uri" and "job-printer-uri" attribute, see the discussion in section 2.4 on "Object Identity".

4.3.3 job-printer-uri (uri)

This REQUIRED attribute identifies the Printer object that created this Job object. When a Printer object creates a Job object, it populates this attribute with the Printer object URI that was used in the create request. This attribute permits a client to identify the Printer object that created this Job object when only the Job object's URI is available to the client. The client queries the creating Printer object to determine which languages, charsets, operations, are supported for this Job.

For a description of this attribute and its relationship to "job-uri" and "job-id" attribute, see the discussion in section 2.4 on "Object Identity".

4.3.4 job-more-info (uri)

Similar to "printer-more-info", this attribute contains the URI referencing some resource with more information about this Job object, perhaps an HTML page containing information about the Job.

4.3.5 job-name (name(MAX))

   This REQUIRED attribute is the name of the job.  It is a name that is
   more user friendly than the "job-uri" attribute value.  It does not
   need to be unique between Jobs.  The Job's "job-name" attribute is
   set to the value supplied by the client in the "job-name" operation
   attribute in the create request (see Section 3.2.1.1).   If, however,
   the "job-name" operation attribute is not supplied by the client in
   the create request, the Printer object, on creation of the Job, MUST
   generate a name.  The printer SHOULD generate the value of the Job's
   "job-name" attribute from the first of the following sources that
   produces a value: 1) the "document-name" operation attribute of the

first (or only) document, 2) the "document-URI" attribute of the first (or only) document, or 3) any other piece of Job specific and/or Document Content information.

4.3.6 job-originating-user-name (name(MAX))

This REQUIRED attribute contains the name of the end user that submitted the print job. The Printer object sets this attribute to the most authenticated printable name that it can obtain from the authentication service over which the IPP operation was received. Only if such is not available, does the Printer object use the value supplied by the client in the "requesting-user-name" operation attribute of the create operation (see Sections 4.4.2, 4.4.3, and 8).

   Note:  The Printer object needs to keep an internal originating user
   id of some form, typically as a credential of a principal, with the
   Job object.  Since such an internal attribute is implementation-
   dependent and not of interest to clients, it is not specified as a
   Job Description attribute.  This originating user id is used for
   authorization checks (if any) on all subsequent operations.

4.3.7 job-state (type1 enum)

This REQUIRED attribute identifies the current state of the job. Even though the IPP protocol defines seven values for job states (plus the out-of-band 'unknown' value - see Section 4.1), implementations only need to support those states which are appropriate for the particular implementation. In other words, a Printer supports only those job states implemented by the output device and available to the Printer object implementation.

Standard enum values are:

Values Symbolic Name and Description

   '3'  'pending':  The job is a candidate to start processing, but is
           not yet processing.
   
   '4'  'pending-held':  The job is not a candidate for processing for
           any number of reasons but will return to the 'pending'
           state as soon as the reasons are no longer present.  The
           job's "job-state-reason" attribute MUST indicate why the
           job is no longer a candidate for processing.
   
   '5'  'processing':  One or more of:

1. the job is using, or is attempting to use, one or more purely software processes that are analyzing, creating, or interpreting a PDL, etc.,
2. the job is using, or is attempting to use, one or more hardware devices that are interpreting a PDL, making marks on a medium, and/or performing finishing, such as stapling, etc.,
3. the Printer object has made the job ready for printing, but the output device is not yet printing it, either because the job hasn't reached the output device or because the job is queued in the output device or some other spooler, awaiting the output device to print it.

When the job is in the 'processing' state, the entire job state includes the detailed status represented in the Printer object's "printer-state", "printer-state- reasons", and "printer-state-message" attributes.

           Implementations MAY, though they NEED NOT,  include
           additional values in the job's "job-state-reasons"
           attribute to indicate the progress of the job, such as
           adding the 'job-printing' value to indicate when the
           output device is actually making marks on paper and/or
           the 'processing-to-stop-point' value to indicate that the
           IPP object is in the process of canceling or aborting the
           job.  Most implementations won't bother with this nuance.
   
   '6'  'processing-stopped':  The job has stopped while processing
           for any number of reasons and will return to the
           'processing' state as soon as the reasons are no longer
           present.

The job's "job-state-reason" attribute MAY indicate why the job has stopped processing. For example, if the output device is stopped, the 'printer-stopped' value MAY be included in the job's "job-state-reasons" attribute.

           Note:  When an output device is stopped, the device
           usually indicates its condition in human readable form
           locally at the device.  A client can obtain more complete
           device status remotely by querying the Printer object's
           "printer-state", "printer-state-reasons" and "printer-
           state-message" attributes.
   
   '7'  'canceled':  The job has been canceled by a Cancel-Job
           operation and the Printer object has completed canceling
           the job and all job status attributes have reached their
           final values for the job.  While the Printer object is
           canceling the job, the job remains in its current state,
           but the job's "job-state-reasons" attribute SHOULD
           contain the 'processing-to-stop-point' value and one of
           the 'canceled-by-user', 'canceled-by-operator', or
           'canceled-at-device' value.  When the job moves to the
           'canceled' state, the  'processing-to-stop-point' value,
           if present, MUST be removed, but the 'canceled-by-xxx',
           if present, MUST remain.
   
   '8'  'aborted':  The job has been aborted by the system, usually
           while the job was in the 'processing' or 'processing-
           stopped' state and the Printer has completed aborting the
           job and all job status attributes have reached their
           final values for the job.  While the Printer object is
           aborting the job, the job remains in its current state,
           but the job's "job-state-reasons" attribute SHOULD
           contain the 'processing-to-stop-point' and 'aborted-by-
           system' values.  When the job moves to the 'aborted'
           state, the  'processing-to-stop-point' value, if present,
           MUST be removed, but the 'aborted-by-system' value, if
           present, MUST remain.
   
   '9'  'completed':  The job has completed successfully or with
           warnings or errors after processing and all of the job
           media sheets have been successfully stacked in the
           appropriate output bin(s) and all job status attributes
           have reached their final values for the job.  The job's
           "job-state-reasons" attribute SHOULD contain one of:
           'completed-successfully', 'completed-with-warnings', or
           'completed-with-errors' values.

The final value for this attribute MUST be one of: 'completed', 'canceled', or 'aborted' before the Printer removes the job altogether. The length of time that jobs remain in the 'canceled', 'aborted', and 'completed' states depends on implementation. See section 4.3.7.2.

The following figure shows the normal job state transitions.

                                                      +----> canceled
                                                     /
       +----> pending --------> processing ---------+------> completed
       |         ^                   ^               \
   --->+         |                   |                +----> aborted
       |         v                   v               /
       +----> pending-held    processing-stopped ---+

Normally a job progresses from left to right. Other state transitions are unlikely, but are not forbidden. Not shown are the transitions to the 'canceled' state from the 'pending', 'pending- held', and 'processing-stopped' states.

Jobs reach one of the three terminal states: 'completed', 'canceled', or 'aborted', after the jobs have completed all activity, including stacking output media, after the jobs have completed all activity, and all job status attributes have reached their final values for the job.

4.3.7.1 Forwarding Servers

   As with all other IPP attributes, if the implementation cannot
   determine the correct value for this attribute, it SHOULD respond
   with the out-of-band value 'unknown' (see section 4.1) rather than
   try to guess at some possibly incorrect value and give the end user
   the wrong impression about the state of the Job object.  For example,
   if the implementation is just a gateway into some printing system
   from which it can normally get status, but temporarily is unable,
   then the implementation should return the 'unknown' value.  However,
   if the implementation is a gateway to a printing system that never
   provides detailed status about the print job, the implementation MAY
   set the IPP Job object's state  to 'completed', provided that it also
   sets the 'queued-in-device' value in the job's "job-state-reasons"
   attribute (see section 4.3.8).

4.3.7.2 Partitioning of Job States

   This section partitions the 7 job states into phases:  Job Not
   Completed, Job Retention, Job History, and Job Removal.  This section
   also explains the 'job-restartable' value of the "job-state-reasons"
   Job Description attribute for use with the Restart-Job operation.
   
   Job Not Completed:  When a job is in the 'pending', 'pending-held',
   'processing', or 'processing-stopped' states, the job is not
   completed.
   
   Job Retention:  When a job enters one of the three terminal job
   states:  'completed', 'canceled', or 'aborted', the IPP Printer
   object MAY "retain" the job in a restartable condition for an
   implementation-defined time period.  This time period MAY be zero
   seconds and MAY depend on the terminal job state.  This phase is
   called Job Retention.  While in the Job Retention phase, the job's
   document data is retained and a client may restart the job using the
   Restart-Job operation.  If the IPP object supports the Restart-Job

operation, then it SHOULD indicate that the job is restartable by adding the 'job-restartable' value to the job's "job-state-reasons" attribute (see Section 4.3.8) during the Job Retention phase.

   Job History:  After the Job Retention phase expires for a job, the
   Printer object deletes the document data for the job and the job
   becomes part of the Job History.  The Printer object MAY also delete
   any number of the job attributes.  Since the job is no longer
   restartable, the Printer object MUST remove the 'job-restartable'
   value from the job's "job-state-reasons" attribute, if present.
   
   Job Removal:  After the job has remained in the Job History for an
   implementation-defined time, such as when the number of jobs exceeds
   a fixed number or after a fixed time period (which MAY be zero
   seconds), the IPP Printer removes the job from the system.

Using the Get-Jobs operation and supplying the 'not-completed' value for the "which-jobs" operation attribute, a client is requesting jobs in the Job Not Completed phase. Using the Get-Jobs operation and supplying the 'completed' value for the "which-jobs" operation attribute, a client is requesting jobs in the Job Retention and Job History phases. Using the Get-Job-Attributes operation, a client is requesting a job in any phase except Job Removal. After Job Removal, the Get-Job-Attributes and Get-Jobs operations no longer are capable of returning any information about a job.

4.3.8 job-state-reasons (1setOf type2 keyword)

This REQUIRED attribute provides additional information about the job's current state, i.e., information that augments the value of the job's "job-state" attribute.

These values MAY be used with any job state or states for which the reason makes sense. Some of these value definitions indicate conformance requirements; the rest are OPTIONAL. Furthermore, when implemented, the Printer MUST return these values when the reason applies and MUST NOT return them when the reason no longer applies whether the value of the Job's "job-state" attribute changed or not. When the Job does not have any reasons for being in its current state, the value of the Job's "job-state-reasons" attribute MUST be 'none'.

Note: While values cannot be added to the 'job-state' attribute without impacting deployed clients that take actions upon receiving "job-state" values, it is the intent that additional "job-state- reasons" values can be defined and registered without impacting such deployed clients. In other words, the "job-state-reasons" attribute is intended to be extensible.

The following standard keyword values are defined. For ease of understanding, the values are presented in the order in which the reasons are likely to occur (if implemented), starting with the 'job-incoming' value:

      'none':  There are no reasons for the job's current state.  This
         state reason is semantically equivalent to "job-state-reasons"
         without any value and MUST be used when there is no other
         value, since the 1setOf attribute syntax requires at least one
         value.
      'job-incoming':  Either (1) the Printer has accepted the Create-
         Job operation and is expecting additional Send-Document and/or
         Send-URI operations, or (2) the Printer is retrieving/accepting
         document data as a result of a Print-Job, Print-URI, Send-
         Document or Send-URI operation.
      'job-data-insufficient':  The Create-Job operation has been
         accepted by the Printer, but the Printer is expecting
         additional document data before it can move the job into the
         'processing' state.  If a Printer starts processing before it
         has received all data, the Printer removes the 'job-data-
         insufficient' reason, but the 'job-incoming' remains.  If a
         Printer starts processing after it has received all data, the
         Printer removes the 'job-data-insufficient' reason and the
         'job-incoming' at the same time.
      'document-access-error':  After accepting a Print-URI or Send-URI
         request, the Printer could not access one or more documents
         passed by reference.  This reason is intended to cover any file
         access problem, including file does not exist and access denied
         because of an access control problem.  The Printer MAY also
         indicate the document access error using the "job-document-
         access-errors" Job Description attribute (see section 4.3.11).
         Whether the Printer aborts the job and moves the job to the
         'aborted' job state or prints all documents that are accessible
         and moves the job to the 'completed' job state and adds the
         'completed-with-errors' value in the job's "job-state-reasons"
         attribute depends on implementation and/or site policy.  This
         value SHOULD be supported if the Print-URI or Send-URI
         operations are supported.
      'submission-interrupted':  The job was not completely submitted
         for some unforeseen reason, such as: (1) the Printer has
         crashed before the job was closed by the client, (2) the
         Printer or the document transfer method has crashed in some
         non-recoverable way before the document data was entirely
         transferred to the Printer, (3) the client crashed or failed to
         close the job before the time-out period.  See section 4.4.31.
      'job-outgoing':  The Printer is transmitting the job to the output
         device.
      'job-hold-until-specified':  The value of the job's "job-hold-
         until" attribute was specified with a time period that is still
         in the future.  The job MUST NOT be a candidate for processing
         until this reason is removed and there are no other reasons to
         hold the job.  This value SHOULD be supported if the "job-
         hold-until" Job Template attribute is supported.
      'resources-are-not-ready':  At least one of the resources needed
         by the job, such as media, fonts, resource objects, etc., is
         not ready on any of the physical printer's for which the job is
         a candidate.  This condition MAY be detected when the job is
         accepted, or subsequently while the job is pending or
         processing, depending on implementation.  The job may remain in
         its current state or be moved to the 'pending-held' state,
         depending on implementation and/or job scheduling policy.
      'printer-stopped-partly':  The value of the Printer's "printer-
         state-reasons" attribute contains the value 'stopped-partly'.
      'printer-stopped':  The value of the Printer's "printer-state"
         attribute is 'stopped'.
      'job-interpreting': Job is in the 'processing' state, but more
         specifically, the Printer is interpreting the document data.
      'job-queued': Job is in the 'processing' state, but more
         specifically, the Printer has queued the document data.
      'job-transforming': Job is in the 'processing' state, but more
         specifically, the Printer is interpreting document data and
         producing another electronic representation.
      'job-queued-for-marker': Job is in any of the 'pending-held',
         'pending', or 'processing' states, but more specifically, the
         Printer has completed enough processing of the document to be
         able to start marking and the job is waiting for the marker.
         Systems that require human intervention to release jobs using
         the Release-Job operation, put the job into the 'pending-held'
         job state.  Systems that automatically select a job to use the
         marker put the job into the  'pending' job state or keep the
         job in the 'processing' job state while waiting for the marker,
         depending on implementation.  All implementations put the job
         into (or back into) the 'processing' state when marking does
         begin.
      'job-printing':  The output device is marking media. This value is
         useful for Printers which spend a great deal of time processing
         (1) when no marking is happening and then want to show that
         marking is now happening or (2) when the job is in the process
         of being canceled or aborted while the job remains in the
         'processing' state, but the marking has not yet stopped so that
         impression or sheet counts are still increasing for the job.
      'job-canceled-by-user':  The job was canceled by the owner of the
         job using the Cancel-Job request, i.e., by a user whose
         authenticated identity is the same as the value of the
         originating user that created the Job object, or by some other
         authorized end-user, such as a member of the job owner's
         security group.  This value SHOULD be supported.
      'job-canceled-by-operator':  The job was canceled by the operator
         using the Cancel-Job request, i.e., by a user who has been
         authenticated as having operator privileges (whether local or
         remote).  If the security policy is to allow anyone to cancel
         anyone's job, then this value may be used when the job is
         canceled by other than the owner of the job.  For such a
         security policy, in effect, everyone is an operator as far as
         canceling jobs with IPP is concerned.  This value SHOULD be
         supported if the implementation permits canceling by other than
         the owner of the job.
      'job-canceled-at-device':  The job was canceled by an unidentified
         local user, i.e., a user at a console at the device.  This
         value SHOULD be supported if the implementation supports
         canceling jobs at the console.
      'aborted-by-system':  The job (1) is in the process of being
         aborted, (2) has been aborted by the system and placed in the
         'aborted' state, or (3) has been aborted by the system and
         placed in the 'pending-held' state, so that a user or operator
         can manually try the job again.  This value SHOULD be
         supported.
      'unsupported-compression': The job was aborted by the system
         because the Printer determined while attempting to decompress
         the document-data's that the compression is actually not among
         those supported by the Printer.  This value MUST be supported,
         since "compressions is a REQUIRED operation attribute.
      'compression-error': The job was aborted by the system because the
         Printer encountered an error in the document-data while
         decompressing it.  If the Printer posts this reason, the
         document-data has already passed any tests that would have led
         to the 'unsupported-compression' job-state-reason.
      'unsupported-document-format': The job was aborted by the system
         because the document-data's document-format is not among those
         supported by the Printer.  If the client specifies the
         document-format as 'application/octet-stream', the printer MAY
         abort the job and post this reason even though the format is a
         member of the "document-format-supported" printer attribute,
         but not among the auto-sensed document-formats.  This value
         MUST be supported, since "document-format" is a REQUIRED
         operation attribute.
      'document-format-error': The job was aborted by the system because
         the Printer encountered an error in the document-data while
         processing it.  If the Printer posts this reason, the
         document-data has already passed any tests that would have led
         to the 'unsupported-document-format' job-state-reason.
      'processing-to-stop-point':  The requester has issued a Cancel-Job
         operation or the Printer object has aborted the job, but is
         still performing some actions on the job until a specified stop
         point occurs or job termination/cleanup is completed.

If the implementation requires some measurable time to cancel the job in the 'processing' or 'processing-stopped' job states, the IPP object MUST use this value to indicate that the Printer object is still performing some actions on the job while the job remains in the 'processing' or 'processing-stopped' state. After all the job's job description attributes have stopped incrementing, the Printer object moves the job from the 'processing' state to the 'canceled' or
'aborted' job states.

      'service-off-line':  The Printer is off-line and accepting no
         jobs.  All 'pending' jobs are put into the 'pending-held'
         state.  This situation could be true if the service's or
         document transform's input is impaired or broken.
      'job-completed-successfully':  The job completed successfully.
         This value SHOULD be supported.
      'job-completed-with-warnings':  The job completed with warnings.
         This value SHOULD be supported if the implementation detects
         warnings.
      'job-completed-with-errors':  The job completed with errors (and
         possibly warnings too).  This value SHOULD be supported if the
         implementation detects errors.
      'job-restartable' - This job is retained (see section 4.3.7.2) and
         is currently able to be restarted using the Restart-Job
         operation (see section 3.3.7).  If 'job-restartable' is a value
         of the job's 'job-state-reasons' attribute, then the IPP object
         MUST accept a Restart-Job operation for that job.  This value
         SHOULD be supported if the Restart-Job operation is supported.
      'queued-in-device': The job has been forwarded to a device or
         print system that is unable to send back status.  The Printer
         sets the job's "job-state " attribute to 'completed'  and adds
         the 'queued-in-device' value to the job's "job-state-reasons"
         attribute to indicate that the Printer has no additional
         information about the job and never will have any better
         information.  See section 4.3.7.1.

4.3.9 job-state-message (text(MAX))

This attribute specifies information about the "job-state" and "job- state-reasons" attributes in human readable text. If the Printer object supports this attribute, the Printer object MUST be able to generate this message in any of the natural languages identified by the Printer's "generated-natural-language-supported" attribute (see the "attributes-natural-language" operation attribute specified in Section 3.1.4.1).

The value SHOULD NOT contain additional information not contained in the values of the "job-state" and "job-states-reasons" attributes, such as interpreter error information. Otherwise, application programs might attempt to parse the (localized text). For such additional information such as interpreter errors for application program consumption or specific document access errors, new attributes with keyword values, needs to be developed and registered.

4.3.10 job-detailed-status-messages (1setOf text(MAX))

This attribute specifies additional detailed and technical information about the job. The Printer NEED NOT localize the message(s), since they are intended for use by the system administrator or other experienced technical persons. Localization might obscure the technical meaning of such messages. Clients MUST NOT attempt to parse the value of this attribute. See "job- document-access-errors" (section 4.3.11) for additional errors that a program can process.

4.3.11 job-document-access-errors (1setOf text(MAX))

This attribute provides additional information about each document access error for this job encountered by the Printer after it returned a response to the Print-URI or Send-URI operation and subsequently attempted to access document(s) supplied in the Print- URI or Send-URI operation. For errors in the protocol that is identified by the URI scheme in the "document-uri" operation attribute, such as 'http:' or 'ftp:', the error code is returned in parentheses, followed by the URI. For example:

      (404) http://ftp.pwg.org/pub/pwg/ipp/new_MOD/ipp-model-v11.pdf

Most Internet protocols use decimal error codes (unlike IPP), so the ASCII error code representation is in decimal.

4.3.12 number-of-documents (integer(0:MAX))

This attribute indicates the number of documents in the job, i.e., the number of Send-Document, Send-URI, Print-Job, or Print-URI operations that the Printer has accepted for this job, regardless of whether the document data has reached the Printer object or not.

Implementations supporting the OPTIONAL Create-Job/Send- Document/Send-URI operations SHOULD support this attribute so that clients can query the number of documents in each job.

4.3.13 output-device-assigned (name(127))

This attribute identifies the output device to which the Printer object has assigned this job. If an output device implements an embedded Printer object, the Printer object NEED NOT set this attribute. If a print server implements a Printer object, the value MAY be empty (zero- length string) or not returned until the Printer object assigns an output device to the job. This attribute is particularly useful when a single Printer object supports multiple devices (so called "fan-out" - see section 2.1).

4.3.14 Event Time Job Description Attributes

This section defines the Job Description attributes that indicate the time at which certain events occur for a job. If the job event has not yet occurred, then the IPP object MUST return the 'no-value' out-of-band value (see the beginning of Section 4.1). The "time-at- xxx(integer)" attributes represent time as an 'integer' representing the number of seconds since the device was powered up (informally called "time ticks"). The "date-time-at-xxx(dateTime)" attributes represent time as 'dateTime' representing date and time (including an offset from UTC).

In order to populate these attributes, the Printer object copies the value(s) of the following Printer Description attributes at the time the event occurs:

the value in the Printer's "printer-up-time" attribute for the "time-at-xxx(integer)" attributes

the value in the Printer's "printer-current-time" attribute for the "date-time-at-xxx(dateTime)" attributes.

If the Printer resets its "printer-up-time" attribute to 1 on power- up (see section 4.4.29) and has persistent jobs, then it MUST change all of jobs' "time-at-xxx(integer)" (time tick) job attributes whose events have occurred either to:

0 to indicate that the event happened before the most recent power up OR

the negative of the number of seconds before the most recent power-up that the event took place, though the negative number NEED NOT reflect the exact number of seconds.

If a client queries a "time-at-xxx(integer)" time tick Job attribute and finds the value to be 0 or negative, the client MUST assume that the event occurred in some life other than the Printer's current life.

Note: A Printer does not change the values of any "date-time-at- xxx(dateTime)" job attributes on power-up.

4.3.14.1 time-at-creation (integer(MIN:MAX))

This REQUIRED attribute indicates the time at which the Job object was created.

4.3.14.2 time-at-processing (integer(MIN:MAX))

This REQUIRED attribute indicates the time at which the Job object first began processing after the create operation or the most recent Restart-Job operation. The out-of-band 'no-value' value is returned if the job has not yet been in the 'processing' state (see the beginning of Section 4.1).

4.3.14.3 time-at-completed (integer(MIN:MAX))

This REQUIRED attribute indicates the time at which the Job object completed (or was canceled or aborted). The out-of-band 'no-value' value is returned if the job has not yet completed, been canceled, or aborted (see the beginning of Section 4.1).

4.3.14.4 job-printer-up-time (integer(1:MAX))

This REQUIRED Job Description attribute indicates the amount of time (in seconds) that the Printer implementation has been up and running. This attribute is an alias for the "printer-up-time" Printer Description attribute (see Section 4.4.29).

A client MAY request this attribute in a Get-Job-Attributes or Get- Jobs request and use the value returned in combination with other requested Event Time Job Description Attributes in order to display time attributes to a user. The difference between this attribute and the 'integer' value of a "time-at-xxx" attribute is the number of seconds ago that the "time-at-xxx" event occurred. A client can compute the wall-clock time at which the "time-at-xxx" event occurred by subtracting this difference from the client's wall-clock time.

4.3.14.5 date-time-at-creation (dateTime)

This attribute indicates the date and time at which the Job object was created.

4.3.14.6 date-time-at-processing (dateTime)

This attribute indicates the date and time at which the Job object first began processing after the create operation or the most recent Restart-Job operation.

4.3.14.7 date-time-at-completed (dateTime)

This attribute indicates the date and time at which the Job object completed (or was canceled or aborted).

4.3.15 number-of-intervening-jobs (integer(0:MAX))

This attribute indicates the number of jobs that are "ahead" of this job in the relative chronological order of expected time to complete (i.e., the current scheduled order). For efficiency, it is only necessary to calculate this value when an operation is performed that requests this attribute.

4.3.16 job-message-from-operator (text(127))

This attribute provides a message from an operator, system administrator or "intelligent" process to indicate to the end user the reasons for modification or other management action taken on a job.

4.3.17 Job Size Attributes

This sub-section defines job attributes that describe the size of the job. These attributes are not intended to be counters; they are intended to be useful routing and scheduling information if known. For these attributes, the Printer object may try to compute the value if it is not supplied in the create request. Even if the client does supply a value for these three attributes in the create request, the Printer object MAY choose to change the value if the Printer object is able to compute a value which is more accurate than the client supplied value. The Printer object may be able to determine the correct value for these attributes either right at job submission time or at any later point in time.

4.3.17.1 job-k-octets (integer(0:MAX))

This attribute specifies the total size of the document(s) in K octets, i.e., in units of 1024 octets requested to be processed in the job. The value MUST be rounded up, so that a job between 1 and 1024 octets MUST be indicated as being 1, 1025 to 2048 MUST be 2, etc.

This value MUST NOT include the multiplicative factors contributed by the number of copies specified by the "copies" attribute, independent of whether the device can process multiple copies without making multiple passes over the job or document data and independent of whether the output is collated or not. Thus the value is independent of the implementation and indicates the size of the document(s) measured in K octets independent of the number of copies.

This value MUST also not include the multiplicative factor due to a copies instruction embedded in the document data. If the document data actually includes replications of the document data, this value will include such replication. In other words, this value is always the size of the source document data, rather than a measure of the hardcopy output to be produced.

4.3.17.2 job-impressions (integer(0:MAX))

This attribute specifies the total size in number of impressions of the document(s) being submitted (see the definition of impression in section 12.2.5).

As with "job-k-octets", this value MUST NOT include the multiplicative factors contributed by the number of copies specified by the "copies" attribute, independent of whether the device can process multiple copies without making multiple passes over the job or document data and independent of whether the output is collated or not. Thus the value is independent of the implementation and reflects the size of the document(s) measured in impressions independent of the number of copies.

As with "job-k-octets", this value MUST also not include the multiplicative factor due to a copies instruction embedded in the document data. If the document data actually includes replications of the document data, this value will include such replication. In other words, this value is always the number of impressions in the source document data, rather than a measure of the number of impressions to be produced by the job.

4.3.17.3 job-media-sheets (integer(0:MAX))

This attribute specifies the total number of media sheets to be produced for this job.

Unlike the "job-k-octets" and the "job-impressions" attributes, this value MUST include the multiplicative factors contributed by the number of copies specified by the "copies" attribute and a 'number of copies' instruction embedded in the document data, if any. This difference allows the system administrator to control the lower and upper bounds of both (1) the size of the document(s) with "job-k- octets-supported" and "job-impressions-supported" and (2) the size of the job with "job-media-sheets-supported".

4.3.18 Job Progress Attributes

This sub-section defines job attributes that describe the progress of the job. These attributes are intended to be counters. That is, the value for a job that has not started processing MUST be 0. When the job's "job-state" is 'processing' or 'processing-stopped', this value is intended to contain the amount of the job that has been processed to the time at which the attributes are requested. When the job enters the 'completed', 'canceled', or 'aborted' states, these values are the final values for the job.

4.3.18.1 job-k-octets-processed (integer(0:MAX))

This attribute specifies the total number of octets processed in K octets, i.e., in units of 1024 octets so far. The value MUST be rounded up, so that a job between 1 and 1024 octets inclusive MUST be indicated as being 1, 1025 to 2048 inclusive MUST be 2, etc.

For implementations where multiple copies are produced by the interpreter with only a single pass over the data, the final value MUST be equal to the value of the "job-k-octets" attribute. For implementations where multiple copies are produced by the interpreter by processing the data for each copy, the final value MUST be a multiple of the value of the "job-k-octets" attribute.

4.3.18.2 job-impressions-completed (integer(0:MAX))

This job attribute specifies the number of impressions completed for the job so far. For printing devices, the impressions completed includes interpreting, marking, and stacking the output.

4.3.18.3 job-media-sheets-completed (integer(0:MAX))

This job attribute specifies the media-sheets completed marking and stacking for the entire job so far whether those sheets have been processed on one side or on both.

4.3.19 attributes-charset (charset)

This REQUIRED attribute is populated using the value in the client supplied "attributes-charset" attribute in the create request. It identifies the charset (coded character set and encoding method) used by any Job attributes with attribute syntax 'text' and 'name' that were supplied by the client in the create request. See Section 3.1.4 for a complete description of the "attributes-charset" operation attribute.

This attribute does not indicate the charset in which the 'text' and 'name' values are stored internally in the Job object. The internal charset is implementation-defined. The IPP object MUST convert from whatever the internal charset is to that being requested in an operation as specified in Section 3.1.4.

4.3.20 attributes-natural-language (naturalLanguage)

This REQUIRED attribute is populated using the value in the client supplied "attributes-natural-language" attribute in the create request. It identifies the natural language used for any Job attributes with attribute syntax 'text' and 'name' that were supplied by the client in the create request. See Section 3.1.4 for a complete description of the "attributes-natural-language" operation attribute. See Sections 4.1.1.2 and 4.1.2.2 for how a Natural Language Override may be supplied explicitly for each 'text' and 'name' attribute value that differs from the value identified by the "attributes-natural-language" attribute.

4.4 Printer Description Attributes

These attributes form the attribute group called "printer- description". The following table summarizes these attributes, their syntax, and whether or not they are REQUIRED for a Printer object to support. If they are not indicated as REQUIRED, they are OPTIONAL. The maximum size in octets for 'text' and 'name' attributes is indicated in parenthesizes.

Note: How these attributes are set by an Administrator is outside the scope of this IPP/1.1 document.

  +----------------------------+---------------------------+-----------+
  |      Attribute             |     Syntax                | REQUIRED? |
  +----------------------------+---------------------------+-----------+
  | printer-uri-supported      | 1setOf uri                |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | uri-security-supported     | 1setOf type2 keyword      |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | uri-authentication-        | 1setOf type2 keyword      |  REQUIRED |
  |     supported              |                           |           |
  +----------------------------+---------------------------+-----------+
  | printer-name               | name (127)                |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-location           | text (127)                |           |
  +----------------------------+---------------------------+-----------+
  | printer-info               | text (127)                |           |
  +----------------------------+---------------------------+-----------+
  | printer-more-info          | uri                       |           |
  +----------------------------+---------------------------+-----------+
  | printer-driver-installer   | uri                       |           |
  +----------------------------+---------------------------+-----------+
  | printer-make-and-model     | text (127)                |           |
  +----------------------------+---------------------------+-----------+
  | printer-more-info-         | uri                       |           |
  | manufacturer               |                           |           |
  +----------------------------+---------------------------+-----------+
  | printer-state              | type1 enum                |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-state-reasons      | 1setOf type2 keyword      |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-state-message      | text (MAX)                |           |
  +----------------------------+---------------------------+-----------+
  | ipp-versions-supported     | 1setOf type2 keyword      |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | operations-supported       | 1setOf type2 enum         |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | multiple-document-jobs-    | boolean                   |           |
  |     supported              |                           |           |
  +----------------------------+---------------------------+-----------+
  | charset-configured         | charset                   |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | charset-supported          | 1setOf charset            |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | natural-language-configured| naturalLanguage           |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | generated-natural-language-| 1setOf naturalLanguage    |  REQUIRED |
  | supported                  |                           |           |
  +----------------------------+---------------------------+-----------+
  | document-format-default    | mimeMediaType             |  REQUIRED |
  
  +----------------------------+---------------------------+-----------+
  | document-format-supported  | 1setOf mimeMediaType      |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-is-accepting-jobs  | boolean                   |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | queued-job-count           | integer (0:MAX)           |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-message-from-      | text (127)                |           |
  | operator                   |                           |           |
  +----------------------------+---------------------------+-----------+
  | color-supported            | boolean                   |           |
  +----------------------------+---------------------------+-----------+
  | reference-uri-schemes-     | 1setOf uriScheme          |           |
  |   supported                |                           |           |
  +----------------------------+---------------------------+-----------+
  | pdl-override-supported     | type2 keyword             |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-up-time            | integer (1:MAX)           |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | printer-current-time       | dateTime                  |           |
  +----------------------------+---------------------------+-----------+
  | multiple-operation-time-out| integer (1:MAX)           |           |
  +----------------------------+---------------------------+-----------+
  | compression-supported      | 1setOf type3 keyword      |  REQUIRED |
  +----------------------------+---------------------------+-----------+
  | job-k-octets-supported     | rangeOfInteger (0:MAX)    |           |
  +----------------------------+---------------------------+-----------+
  | job-impressions-supported  | rangeOfInteger (0:MAX)    |           |
  +----------------------------+---------------------------+-----------+
  | job-media-sheets-supported | rangeOfInteger (0:MAX)    |           |
  +----------------------------+---------------------------+-----------+
  | pages-per-minute           | integer(0:MAX)            |           |
  +----------------------------+---------------------------+-----------+
  | pages-per-minute-color     | integer(0:MAX)            |           |
  +----------------------------+---------------------------+-----------+

4.4.1 printer-uri-supported (1setOf uri)

   This REQUIRED Printer attribute contains at least one URI for the
   Printer object.  It OPTIONALLY contains more than one URI for the
   Printer object.    An administrator determines a Printer object's
   URI(s) and configures this attribute to contain those URIs by some
   means outside the scope of this IPP/1.1 document.  The precise format
   of this URI is implementation dependent and depends on the protocol.
   See the next two sections for a description of the "uri-security-
   supported" and "uri-authentication-supported" attributes, both of

which are the REQUIRED companion attributes to this "printer-uri- supported" attribute. See section 2.4 on Printer object identity and section 8.2 on security and URIs for more information.

4.4.2 uri-authentication-supported (1setOf type2 keyword)

This REQUIRED Printer attribute MUST have the same cardinality (contain the same number of values) as the "printer-uri-supported" attribute. This attribute identifies the Client Authentication mechanism associated with each URI listed in the "printer-uri- supported" attribute. The Printer object uses the specified mechanism to identify the authenticated user (see section 8.3). The "i th" value in "uri-authentication-supported" corresponds to the "i th" value in "printer-uri-supported" and it describes the authentication mechanisms used by the Printer when accessed via that URI. See [RFC2910] for more details on Client Authentication.

The following standard keyword values are defined:

      'none': There is no authentication mechanism associated with the
         URI.  The Printer object assumes that the authenticated user is
         "anonymous".
      'requesting-user-name': When a client performs an operation whose
         target is the associated URI, the Printer object assumes that
         the authenticated user is specified by the "requesting-user-
         name" Operation attribute (see section 8.3). If the
         "requesting-user-name" attribute is absent in a request, the
         Printer object assumes that the authenticated user is
         "anonymous".
      'basic': When a client performs an operation whose target is the
         associated URI, the Printer object challenges the client with
         HTTP basic authentication [RFC2617]. The Printer object assumes
         that the authenticated user is the name received via the basic
         authentication mechanism.
      'digest': When a client performs an operation whose target is the
         associated URI, the Printer object challenges the client with
         HTTP digest authentication [RFC2617]. The Printer object
         assumes that the authenticated user is the name received via
         the digest authentication mechanism.
      'certificate': When a client performs an operation whose target is
         the associated URI, the Printer object expects the client to
         provide a certificate. The Printer object assumes that the
         authenticated user is the textual name contained within the
         certificate.

4.4.3 uri-security-supported (1setOf type2 keyword)

This REQUIRED Printer attribute MUST have the same cardinality (contain the same number of values) as the "printer-uri-supported" attribute. This attribute identifies the security mechanisms used for each URI listed in the "printer-uri-supported" attribute. The "i th" value in "uri-security-supported" corresponds to the "i th" value in "printer-uri-supported" and it describes the security mechanisms used for accessing the Printer object via that URI. See [RFC2910] for more details on security mechanisms.

The following standard keyword values are defined:

      'none': There are no secure communication channel protocols in use
         for the given URI.
      'ssl3': SSL3 [SSL] is the secure communications channel protocol
         in use for the given URI.
      'tls':  TLS [RFC2246] is the secure communications channel
         protocol in use for the given URI.

This attribute is orthogonal to the definition of a Client Authentication mechanism. Specifically, 'none' does not exclude Client Authentication. See section 4.4.2.

   Consider the following example.  For a single Printer object, an
   administrator configures the "printer-uri-supported",  "uri-
   authentication-supported" and "uri-security-supported" attributes as
   follows:
   
     "printer-uri-supported": 'xxx://acme.com/open-use-printer',
        'xxx://acme.com/restricted-use-printer',
        'xxx://acme.com/private-printer'
     "uri-authentication-supported": 'none', 'digest', 'basic'
     "uri-security-supported": 'none', 'none', 'tls'
   
   Note:  'xxx'  is not a valid scheme.  See the IPP/1.1 "Transport and
   Encoding" document [RFC2910] for the actual URI schemes to be used in
   object target attributes.

In this case, one Printer object has three URIs.

      - For the first URI, 'xxx://acme.com/open-use-printer', the value
        'none' in "uri-security-supported" indicates that there is no
        secure channel protocol configured to run under HTTP.  The value
        of 'none' in "uri-authentication-supported" indicates that all
        users are 'anonymous'.  There will be no challenge and the
        Printer will ignore "requesting-user-name".
      
      - For the second URI, 'xxx://acme.com/restricted-use-printer', the
        value 'none' in "uri-security-supported" indicates that there is
        no secure channel protocol configured to run under HTTP. The
        value of 'digest' in "uri-authentication-supported" indicates
        that the Printer will issue a challenge and that the Printer
        will use the name supplied by the digest mechanism to determine
        the authenticated user (see section 8.3).
      - For the third URI, 'xxx://acme.com/private-printer', the value
        'tls' in "uri-security-supported" indicates that TLS is being
        used to secure the channel.  The client SHOULD be prepared to
        use TLS framing to negotiate an acceptable ciphersuite to use
        while communicating with the Printer object.  In this case, the
        name implies the use of a secure communications channel, but the
        fact is made explicit by the presence of the 'tls' value in
        "uri-security-supported".  The client does not need to resort to
        understanding which security it must use by following naming
        conventions or by parsing the URI to determine which security
        mechanisms are implied.  The value of 'basic' in "uri-
        authentication-supported" indicates that the Printer will issue
        a challenge and that the Printer will use the name supplied by
        the digest mechanism to determine the authenticated user (see
        section 8.3).  Because this challenge occurs in a tls session,
        the channel is secure.

It is expected that many IPP Printer objects will be configured to support only one channel (either configured to use TLS access or not) and only one authentication mechanism. Such Printer objects only have one URI listed in the "printer-uri-supported" attribute. No matter the configuration of the Printer object (whether it has only one URI or more than one URI), a client MUST supply only one URI in the target "printer-uri" operation attribute.

4.4.4 printer-name (name(127))

This REQUIRED Printer attribute contains the name of the Printer object. It is a name that is more end-user friendly than a URI. An administrator determines a printer's name and sets this attribute to that name. This name may be the last part of the printer's URI or it may be unrelated. In non-US-English locales, a name may contain characters that are not allowed in a URI.

4.4.5 printer-location (text(127))

This Printer attribute identifies the location of the device. This could include things like: "in Room 123A, second floor of building XYZ".

4.4.6 printer-info (text(127))

This Printer attribute identifies the descriptive information about this Printer object. This could include things like: "This printer can be used for printing color transparencies for HR presentations", or "Out of courtesy for others, please print only small (1-5 page) jobs at this printer", or even "This printer is going away on July 1, 1997, please find a new printer".

4.4.7 printer-more-info (uri)

This Printer attribute contains a URI used to obtain more information about this specific Printer object. For example, this could be an HTTP type URI referencing an HTML page accessible to a Web Browser. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI. The information is intended to be specific to this printer instance and site specific services (e.g. job pricing, services offered, end user assistance). The device manufacturer may initially populate this attribute.

4.4.8 printer-driver-installer (uri)

   This Printer attribute contains a URI to use to locate the driver
   installer for this Printer object.   This attribute is intended for
   consumption by automata.  The mechanics of print driver installation
   is outside the scope of this IPP/1.1 document.  The device
   manufacturer may initially populate this attribute.

4.4.9 printer-make-and-model (text(127))

This Printer attribute identifies the make and model of the device. The device manufacturer may initially populate this attribute.

4.4.10 printer-more-info-manufacturer (uri)

This Printer attribute contains a URI used to obtain more information about this type of device. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI (e.g., latest firmware, upgrades, print drivers, optional features available, details on color support). The information is intended to be germane to this printer without regard to site specific modifications or services. The device manufacturer may initially populate this attribute.

4.4.11 printer-state (type1 enum)

This REQUIRED Printer attribute identifies the current state of the device. The "printer-state reasons" attribute augments the "printer-state" attribute to give more detailed information about the Printer in the given printer state.

A Printer object need only update this attribute before responding to an operation which requests the attribute; the Printer object NEED NOT update this attribute continually, since asynchronous event notification is not part of IPP/1.1. A Printer NEED NOT implement all values if they are not applicable to a given implementation.

The following standard enum values are defined:

   Value  Symbolic Name and Description
   
   '3'    'idle':  Indicates that new jobs can start processing without
                waiting.
   '4'    'processing':  Indicates that jobs are processing; new jobs
                will wait before processing.
   '5'    'stopped':  Indicates that no jobs can be processed and
                intervention is required.

Values of "printer-state-reasons", such as 'spool-area-full' and 'stopped-partly', MAY be used to provide further information.

4.4.12 printer-state-reasons (1setOf type2 keyword)

This REQUIRED Printer attribute supplies additional detail about the device's state. Some of the these value definitions indicate conformance requirements; the rest are OPTIONAL.

Each keyword value MAY have a suffix to indicate its level of severity. The three levels are: report (least severe), warning, and error (most severe).

      - '-report':  This suffix indicates that the reason is a "report".
        An implementation may choose to omit some or all reports. Some
        reports specify finer granularity about the printer state;
        others serve as a precursor to a warning. A report MUST contain
        nothing that could affect the printed output.
      - '-warning': This suffix indicates that the reason is a
        "warning".  An implementation may choose to omit some or all
        warnings. Warnings serve as a precursor to an error. A warning
        MUST contain nothing that prevents a job from completing, though
        in some cases the output may be of lower quality.

'-error': This suffix indicates that the reason is an "error". An implementation MUST include all errors. If this attribute contains one or more errors, printer MUST be in the stopped state.

If the implementation does not add any one of the three suffixes, all parties MUST assume that the reason is an "error".

If a Printer object controls more than one output device, each value of this attribute MAY apply to one or more of the output devices. An error on one output device that does not stop the Printer object as a whole MAY appear as a warning in the Printer's "printer-state-reasons attribute". If the "printer-state" for such a Printer has a value of 'stopped', then there MUST be an error reason among the values in the "printer-state-reasons" attribute.

The following standard keyword values are defined:

      'other': The device has detected an error other than one listed in
         this document.
      'none': There are not reasons. This state reason is semantically
         equivalent to "printer-state-reasons" without any value and
         MUST be used, since the 1setOf attribute syntax requires at
         least one value.
      'media-needed': A tray has run out of media.
      'media-jam': The device has a media jam.
      'moving-to-paused':  Someone has paused the Printer object using
         the Pause-Printer operation (see section 3.2.7) or other means,
         but the device(s) are taking an appreciable time to stop.
         Later, when all output has stopped, the "printer-state" becomes
         'stopped', and the 'paused' value replaces the 'moving-to-
         paused' value in the "printer-state-reasons" attribute.  This
         value MUST be supported, if the Pause-Printer operation is
         supported and the implementation takes significant time to
         pause a device in certain circumstances.
      'paused': Someone has paused the Printer object using the Pause-
         Printer operation (see section 3.2.7) or other means and the
         Printer object's "printer-state" is 'stopped'.  In this state,
         a Printer MUST NOT produce printed output, but it MUST perform
         other operations requested by a client.  If a Printer had been
         printing a job when the Printer was paused, the Printer MUST
         resume printing that job when the Printer is no longer paused
         and leave no evidence in the printed output of such a pause.
         This value MUST be supported, if the Pause-Printer operation is
         supported.
      'shutdown': Someone has removed a Printer object from service, and
         the device may be powered down or physically removed.  In this
         state, a Printer object MUST NOT produce printed output, and
         unless the Printer object is realized by a print server that is
         still active, the Printer object MUST perform no other
         operations requested by a client, including returning this
         value. If a Printer object had been printing a job when it was
         shutdown, the Printer NEED NOT resume printing that job when
         the Printer is no longer shutdown. If the Printer resumes
         printing such a job, it may leave evidence in the printed
         output of such a shutdown, e.g. the part printed before the
         shutdown may be printed a second time after the shutdown.
      'connecting-to-device': The Printer object has scheduled a job on
         the output device and is in the process of connecting to a
         shared network output device (and might not be able to actually
         start printing the job for an arbitrarily long time depending
         on the usage of the output device by other servers on the
         network).
      'timed-out': The server was able to connect to the output device
         (or is always connected), but was unable to get a response from
         the output device.
      'stopping': The Printer object is in the process of stopping the
         device and will be stopped in a while. When the device is
         stopped, the Printer object will change the Printer object's
         state to 'stopped'.  The 'stopping-warning' reason is never an
         error, even for a Printer with a single output device.  When an
         output-device ceases accepting jobs, the Printer will have this
         reason while the output device completes printing.
      'stopped-partly': When a Printer object controls more than one
         output device, this reason indicates that one or more output
         devices are stopped.  If the reason is a report, fewer than
         half of the output devices are stopped.  If the reason is a
         warning, fewer than all of the output devices are stopped.
      'toner-low': The device is low on toner.
      'toner-empty':  The device is out of toner.
      'spool-area-full': The limit of persistent storage allocated for
         spooling has been reached.  The Printer is temporarily unable
         to accept more jobs.  The Printer will remove this value when
         it is able to accept more jobs.  This value SHOULD be used by a
         non-spooling Printer that only accepts one or a small number
         jobs at a time or a spooling Printer that has filled the spool
         space.
      'cover-open': One or more covers on the device are open.
      'interlock-open': One or more interlock devices on the printer are
         unlocked.
      'door-open': One or more doors on the device are open.
      'input-tray-missing': One or more input trays are not in the
         device.
      'media-low': At least one input tray is low on media.
      'media-empty': At least one input tray is empty.
      'output-tray-missing': One or more output trays are not in the
         device
      'output-area-almost-full': One or more output area is almost full
         (e.g. tray, stacker, collator).
      'output-area-full': One or more output area is full. (e.g. tray,
         stacker, collator)
      'marker-supply-low': The device is low on at least one marker
         supply.  (e.g. toner, ink, ribbon)
      'marker-supply-empty: The device is out of at least one marker
         supply. (e.g. toner, ink, ribbon)
      'marker-waste-almost-full': The device marker supply waste
         receptacle is almost full.
      'marker-waste-full': The device marker supply waste receptacle is
         full.
      'fuser-over-temp': The fuser temperature is above normal.
      'fuser-under-temp': The fuser temperature is below normal.
      'opc-near-eol': The optical photo conductor is near end of life.
      'opc-life-over': The optical photo conductor is no longer
         functioning.
      'developer-low': The device is low on developer.
      'developer-empty: The device is out of developer.
      'interpreter-resource-unavailable': An interpreter resource is
         unavailable (i.e. font, form)

4.4.13 printer-state-message (text(MAX))

This Printer attribute specifies information about the "printer- state" and "printer-state-reasons" attributes in human readable text. If the Printer object supports this attribute, the Printer object MUST be able to generate this message in any of the natural languages identified by the Printer's "generated-natural-language-supported" attribute (see the "attributes-natural-language" operation attribute specified in Section 3.1.4.1).

4.4.14 ipp-versions-supported (1setOf type2 keyword)

This REQUIRED attribute identifies the IPP protocol version(s) that this Printer supports, including major and minor versions, i.e., the version numbers for which this Printer implementation meets the conformance requirements. For version number validation, the Printer matches the (two-octet binary) "version-number" parameter supplied by the client in each request (see sections 3.1.1 and 3.1.8) with the (US-ASCII) keyword values of this attribute.

The following standard keyword values are defined:

      '1.0': Meets the conformance requirement of IPP version 1.0 as
         specified in RFC 2566 [RFC2566] and RFC 2565 [RFC2565]
         including any extensions registered according to Section 6 and
         any extension defined in this version or any future version of
         the IPP "Model and Semantics" document or the IPP "Encoding and
         Transport" document following the rules, if any, when the
         "version-number" parameter is '1.0'.
      '1.1': Meets the conformance requirement of IPP version 1.1 as
         specified in this document and [RFC2910] including any
         extensions registered according to Section 6 and any extension
         defined in any future versions of the IPP "Model and Semantics"
         document or the IPP Encoding and Transport document following
         the rules, if any, when the "version-number" parameter is
         '1.1'.

4.4.15 operations-supported (1setOf type2 enum)

This REQUIRED Printer attribute specifies the set of supported operations for this Printer object and contained Job objects.

This attribute is encoded as any other enum attribute syntax according to [RFC2910] as 32-bits. However, all 32-bit enum values for this attribute MUST NOT exceed 0x00008FFF, since these same values are also passed in two octets in the "operation-id" parameter (see section 3.1.1) in each Protocol request with the two high order octets omitted in order to indicate the operation being performed [RFC2910].

The following standard enum and "operation-id" (see section 3.1.2) values are defined:

     Value               Operation Name
     -----------------   -------------------------------------
     
     0x0000              reserved, not used
     0x0001              reserved, not used
     0x0002              Print-Job
     0x0003              Print-URI
     0x0004              Validate-Job
     0x0005              Create-Job
     0x0006              Send-Document
     0x0007              Send-URI
     0x0008              Cancel-Job
     0x0009              Get-Job-Attributes
     0x000A              Get-Jobs
     0x000B              Get-Printer-Attributes
     0x000C              Hold-Job
     0x000D              Release-Job
     0x000E              Restart-Job
     0x000F              reserved for a future operation
     0x0010              Pause-Printer
     0x0011              Resume-Printer
     0x0012              Purge-Jobs
     0x0013-0x3FFF       reserved for future IETF standards track
                         operations (see section 6.4)
     0x4000-0x8FFF       reserved for vendor extensions (see section 6.4)

4.4.16 multiple-document-jobs-supported (boolean)

This Printer attribute indicates whether or not the Printer supports more than one document per job, i.e., more than one Send-Document or Send-Data operation with document data. If the Printer supports the Create-Job and Send-Document operations (see section 3.2.4 and 3.3.1), it MUST support this attribute.

4.4.17 charset-configured (charset)

This REQUIRED Printer attribute identifies the charset that the Printer object has been configured to represent 'text' and 'name' Printer attributes that are set by the operator, system administrator, or manufacturer, i.e., for "printer-name" (name), "printer-location" (text), "printer-info" (text), and "printer-make- and-model" (text). Therefore, the value of the Printer object's "charset-configured" attribute MUST also be among the values of the Printer object's "charset-supported" attribute.

4.4.18 charset-supported (1setOf charset)

This REQUIRED Printer attribute identifies the set of charsets that the Printer and contained Job objects support in attributes with attribute syntax 'text' and 'name'. At least the value 'utf-8' MUST be present, since IPP objects MUST support the UTF-8 [RFC2279] charset. If a Printer object supports a charset, it means that for all attributes of syntax 'text' and 'name' the IPP object MUST (1) accept the charset in requests and return the charset in responses as needed.

If more charsets than UTF-8 are supported, the IPP object MUST perform charset conversion between the charsets as described in Section 3.1.4.2.

4.4.19 natural-language-configured (naturalLanguage)

This REQUIRED Printer attribute identifies the natural language that the Printer object has been configured to represent 'text' and 'name' Printer attributes that are set by the operator, system administrator, or manufacturer, i.e., for "printer-name" (name), "printer-location" (text), "printer-info" (text), and "printer-make- and-model" (text). When returning these Printer attributes, the Printer object MAY return them in the configured natural language specified by this attribute, instead of the natural language requested by the client in the "attributes-natural-language" operation attribute. See Section 3.1.4.1 for the specification of the OPTIONAL multiple natural language support. Therefore, the value of the Printer object's "natural-language-configured" attribute MUST also be among the values of the Printer object's "generated-natural- language-supported" attribute.

4.4.20 generated-natural-language-supported (1setOf naturalLanguage)

This REQUIRED Printer attribute identifies the natural language(s) that the Printer object and contained Job objects support in attributes with attribute syntax 'text' and 'name'. The natural language(s) supported depends on implementation and/or configuration. Unlike charsets, IPP objects MUST accept requests with any natural language or any Natural Language Override whether the natural language is supported or not.

If a Printer object supports a natural language, it means that for any of the attributes for which the Printer or Job object generates messages, i.e., for the "job-state-message" and "printer-state- message" attributes and Operation Messages (see Section 3.1.5) in operation responses, the Printer and Job objects MUST be able to generate messages in any of the Printer's supported natural languages. See section 3.1.4 for the definition of 'text' and 'name' attributes in operation requests and responses.

Note: A Printer object that supports multiple natural languages, often has separate catalogs of messages, one for each natural language supported.

4.4.21 document-format-default (mimeMediaType)

This REQUIRED Printer attribute identifies the document format that the Printer object has been configured to assume if the client does not supply a "document-format" operation attribute in any of the operation requests that supply document data. The standard values for this attribute are Internet Media types (sometimes called MIME types). For further details see the description of the 'mimeMediaType' attribute syntax in Section 4.1.9.

4.4.22 document-format-supported (1setOf mimeMediaType)

This REQUIRED Printer attribute identifies the set of document formats that the Printer object and contained Job objects can support. For further details see the description of the 'mimeMediaType' attribute syntax in Section 4.1.9.

4.4.23 printer-is-accepting-jobs (boolean)

This REQUIRED Printer attribute indicates whether the printer is currently able to accept jobs, i.e., is accepting Print-Job, Print- URI, and Create-Job requests. If the value is 'true', the printer is accepting jobs. If the value is 'false', the Printer object is currently rejecting any jobs submitted to it. In this case, the Printer object returns the 'server-error-not-accepting-jobs' status code.

This value is independent of the "printer-state" and "printer-state- reasons" attributes because its value does not affect the current job; rather it affects future jobs. This attribute, when 'false', causes the Printer to reject jobs even when the "printer-state" is 'idle' or, when 'true', causes the Printer object to accepts jobs even when the "printer-state" is 'stopped'.

4.4.24 queued-job-count (integer(0:MAX))

This REQUIRED Printer attribute contains a count of the number of jobs that are either 'pending', 'processing', 'pending-held', or 'processing-stopped' and is set by the Printer object.

4.4.25 printer-message-from-operator (text(127))

This Printer attribute provides a message from an operator, system administrator or "intelligent" process to indicate to the end user information or status of the printer, such as why it is unavailable or when it is expected to be available.

4.4.26 color-supported (boolean)

This Printer attribute identifies whether the device is capable of any type of color printing at all, including highlight color. All document instructions having to do with color are embedded within the document PDL (none are external IPP attributes in IPP/1.1).

   Note:  end-users are able to determine the nature and details of the
   color support by querying the "printer-more-info-manufacturer"
   Printer attribute.

4.4.27 reference-uri-schemes-supported (1setOf uriScheme)

This Printer attribute specifies which URI schemes are supported for use in the "document-uri" operation attribute of the Print-URI or Send-URI operation. If a Printer object supports these optional operations, it MUST support the "reference-uri-schemes-supported" Printer attribute with at least the following schemed URI value:

      'ftp':  The Printer object will use an FTP 'get' operation as
         defined in RFC 2228 [RFC2228] using FTP URLs as defined by
         [RFC2396] and [RFC2316].

The Printer object MAY OPTIONALLY support other URI schemes (see section 4.1.6).

4.4.28 pdl-override-supported (type2 keyword)

This REQUIRED Printer attribute expresses the ability for a particular Printer implementation to either attempt to override document data instructions with IPP attributes or not.

This attribute takes on the following keyword values:

      - 'attempted': This value indicates that the Printer object
         attempts to make the IPP attribute values take precedence over
         embedded instructions in the document data, however there is no
         guarantee.
      - 'not-attempted': This value indicates that the Printer object
         makes no attempt to make the IPP attribute values take
         precedence over embedded instructions in the document data.

Section 15 contains a full description of how this attribute interacts with and affects other IPP attributes, especially the "ipp-attribute-fidelity" attribute.

4.4.29 printer-up-time (integer(1:MAX))

This REQUIRED Printer attribute indicates the amount of time (in seconds) that this Printer instance has been up and running. The value is a monotonically increasing value starting from 1 when the Printer object is started-up (initialized, booted, etc.). This value is used to populate the Event Time Job Description Job attributes "time-at-creation", "time-at-processing", and "time-at-completed" (see section 4.3.14).

If the Printer object goes down at some value 'n', and comes back up, the implementation MAY:

      1. Know how long it has been down, and resume at some value
         greater than 'n', or
      2. Restart from 1.

In other words, if the device or devices that the Printer object is representing are restarted or power cycled, the Printer object MAY continue counting this value or MAY reset this value to 1 depending on implementation. However, if the Printer object software ceases running, and restarts without knowing the last value for "printer- up-time", the implementation MUST reset this value to 1. If this value is reset and the Printer has persistent jobs, the Printer MUST reset the "time-at-xxx(integer) Event Time Job Description attributes according to Section 4.3.14. An implementation MAY use both implementation alternatives, depending on warm versus cold start, respectively.

4.4.30 printer-current-time (dateTime)

This Printer attribute indicates the current date and time. This value is used to populate the Event Time Job Description attributes: "date-time-at-creation", "date-time-at-processing", and "date-time- at-completed" (see Section 4.3.14).

The date and time is obtained on a "best efforts basis" and does not have to be that precise in order to work in practice. A Printer implementation sets the value of this attribute by obtaining the date and time via some implementation-dependent means, such as getting the value from a network time server, initialization at time of manufacture, or setting by an administrator. See [IPP-IIG] for examples. If an implementation supports this attribute and the implementation knows that it has not yet been set, then the implementation MUST return the value of this attribute using the out-of-band 'no-value' meaning not configured. See the beginning of section 4.1.

The time zone of this attribute NEED NOT be the time zone used by people located near the Printer object or device. The client MUST NOT expect that the time zone of any received 'dateTime' value to be in the time zone of the client or in the time zone of the people located near the printer.

The client SHOULD display any dateTime attributes to the user in client local time by converting the 'dateTime' value returned by the server to the time zone of the client, rather than using the time zone returned by the Printer in attributes that use the 'dateTime' attribute syntax.

4.4.31 multiple-operation-time-out (integer(1:MAX))

   This Printer attributes identifies the minimum time (in seconds) that
   the Printer object waits for additional Send-Document or Send-URI
   operations to follow a still-open Job object before taking  any
   recovery actions, such as the ones indicated in section 3.3.1.  If
   the Printer object supports the Create-Job and Send-Document
   operations (see section 3.2.4 and 3.3.1), it MUST support this
   attribute.

It is RECOMMENDED that vendors supply a value for this attribute that is between 60 and 240 seconds. An implementation MAY allow a system administrator to set this attribute (by means outside this IPP/1.1 document). If so, the system administrator MAY be able to set values outside this range.

4.4.32 compression-supported (1setOf type3 keyword)

This REQUIRED Printer attribute identifies the set of supported compression algorithms for document data. Compression only applies to the document data; compression does not apply to the encoding of the IPP operation itself. The supported values are used to validate the client supplied "compression" operation attributes in Print-Job, Send-Document, and Send-URI requests.

Standard keyword values are :

   'none': no compression is used.
   'deflate':  ZIP public domain inflate/deflate) compression technology
      in RFC 1951 [RFC1951]
   'gzip' GNU zip compression technology described in RFC 1952
      [RFC1952].

'compress':

UNIX compression technology in RFC 1977 [RFC1977]

4.4.33 job-k-octets-supported (rangeOfInteger(0:MAX))

This Printer attribute specifies the upper and lower bounds of total sizes of jobs in K octets, i.e., in units of 1024 octets. The supported values are used to validate the client supplied "job-k- octets" operation attributes in create requests. The corresponding job description attribute "job-k-octets" is defined in section 4.3.17.1.

4.4.34 job-impressions-supported (rangeOfInteger(0:MAX))

This Printer attribute specifies the upper and lower bounds for the number of impressions per job. The supported values are used to validate the client supplied "job-impressions" operation attributes in create requests. The corresponding job description attribute "job-impressions" is defined in section 4.3.17.2.

4.4.35 job-media-sheets-supported (rangeOfInteger(0:MAX))

This Printer attribute specifies the upper and lower bounds for the number of media sheets per job. The supported values are used to validate the client supplied "job-media-sheets" operation attributes in create requests. The corresponding Job attribute "job-media- sheets" is defined in section 4.3.17.3.

4.4.36 pages-per-minute (integer(0:MAX))

This Printer attributes specifies the nominal number of pages per minute to the nearest whole number which may be generated by this printer (e.g., simplex, black-and-white). This attribute is informative, not a service guarantee. Generally, it is the value used in the marketing literature to describe the device.

A value of 0 indicates a device that takes more than two minutes to process a page.

4.4.37 pages-per-minute-color (integer(0:MAX))

This Printer attributes specifies the nominal number of pages per minute to the nearest whole number which may be generated by this printer when printing color (e.g., simplex, color). For purposes of this attribute, "color" means the same as for the "color-supported" attribute, namely, the device is capable of any type of color printing at all, including highlight color. This attribute is informative, not a service guarantee. Generally, it is the value used in the marketing literature to describe the color capabilities of this device.

A value of 0 indicates a device that takes more than two minutes to process a page.

If a color device has several color modes, it MAY use the pages-per- minute value for this attribute that corresponds to the mode that produces the highest number.

Black and white only printers MUST NOT support this attribute. If this attribute is present, then the "color-supported" Printer description attribute MUST be present and have a 'true' value.

The values of these two attributes returned by the Get-Printer- Attributes operation MAY be affected by the "document-format" attribute supplied by the client in the Get-Printer-Attributes request. In other words, the implementation MAY have different speeds depending on the document format being processed. See section 3.2.5.1 Get-Printer-Attributes.

5. Conformance

This section describes conformance issues and requirements. This document introduces model entities such as objects, operations, attributes, attribute syntaxes, and attribute values. These conformance sections describe the conformance requirements which apply to these model entities.

5.1 Client Conformance Requirements

This section describes the conformance requirements for a client (see section 2.1), whether it be:

contained within software controlled by an end user, e.g. activated by the "Print" menu item in an application that sends IPP requests or

the print server component that sends IPP requests to either an output device or another "downstream" print server.

A conforming client MUST support all REQUIRED operations as defined in this document. For each attribute included in an operation request, a conforming client MUST supply a value whose type and value syntax conforms to the requirements of the Model document as specified in Sections 3 and 4. A conforming client MAY supply any

IETF standards track extensions and/or vendor extensions in an operation request, as long as the extensions meet the requirements in Section 6.

Otherwise, there are no conformance requirements placed on the user interfaces provided by IPP clients or their applications. For example, one application might not allow an end user to submit multiple documents per job, while another does. One application might first query a Printer object in order to supply a graphical user interface (GUI) dialogue box with supported and default values whereas a different implementation might not.

When sending a request, an IPP client NEED NOT supply any attributes that are indicated as OPTIONALLY supplied by the client.

A client MUST be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, that may be returned to it in a response from a Printer object. In particular for each attribute that the client supports whose attribute syntax is 'text', the client MUST accept and process both the 'textWithoutLanguage' and 'textWithLanguage' forms. Similarly, for each attribute that the client supports whose attribute syntax is 'name', the client MUST accept and process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms. For presentation purposes, truncation of long attribute values is not recommended. A recommended approach would be for the client implementation to allow the user to scroll through long attribute values.

A response MAY contain attribute groups, attributes, attribute syntaxes, values, and status codes that the client does not expect. Therefore, a client implementation MUST gracefully handle such responses and not refuse to inter-operate with a conforming Printer that is returning IETF standards track extension or vendor extensions, including attribute groups, attributes, attribute syntaxes, attribute values, status codes, and out-of-band attribute values that conform to Section 6. Clients may choose to ignore any parameters, attribute groups, attributes, attribute syntaxes, or values that they do not understand.

While a client is sending data to a printer, it SHOULD do its best to prevent a channel from being closed by a lower layer when the channel is blocked (i.e. flow-controlled off) for whatever reason, e.g. 'out of paper' or 'job ahead hasn't freed up enough memory'. However, the layer that launched the print submission (e.g. an end user) MAY close the channel in order to cancel the job. When a client closes a channel, a Printer MAY print all or part of the received portion of the document. See the "Encoding and Transport" document [RFC2910] for more details.

A client MUST support Client Authentication as defined in the IPP/1.1 Encoding and Transport document [RFC2910]. A client SHOULD support Operation Privacy and Server Authentication as defined in the IPP/1.1 Encoding and Transport document [RFC2910]. See also section 8 of this document.

5.2 IPP Object Conformance Requirements

This section specifies the conformance requirements for conforming implementations of IPP objects (see section 2). These requirements apply to an IPP object whether it is:

(1) an (embedded) device component that accepts IPP requests and controls the device or

(2) a component of a print server that accepts IPP requests (where the print server control one or more networked devices using IPP or other protocols).

5.2.1 Objects

Conforming implementations MUST implement all of the model objects as defined in this document in the indicated sections:

Section 2.1 - Printer Object
Section 2.2 - Job Object

5.2.2 Operations

Conforming IPP object implementations MUST implement all of the REQUIRED model operations, including REQUIRED responses, as defined in this document in the indicated sections:

For a Printer object:

         Print-Job (section 3.2.1)               REQUIRED
         Print-URI (section 3.2.2)               OPTIONAL
         Validate-Job (section 3.2.3)            REQUIRED
         Create-Job (section 3.2.4)              OPTIONAL
         Get-Printer-Attributes (section 3.2.5)  REQUIRED
         Get-Jobs (section 3.2.6)                REQUIRED
         Pause-Printer (section 3.2.7)           OPTIONAL
         Resume-Printer (section 3.2.8)          OPTIONAL
         Purge-Jobs (section 3.2.9)              OPTIONAL

For a Job object:

         Send-Document (section 3.3.1)           OPTIONAL
         Send-URI (section 3.3.2)                OPTIONAL
         Cancel-Job (section 3.3.3)              REQUIRED
         Get-Job-Attributes (section 3.3.4)      REQUIRED
         Hold-Job (section 3.3.5)                OPTIONAL
         Release-Job (section 3.3.6)             OPTIONAL
         Restart-Job (section 3.3.7)             OPTIONAL

Conforming IPP objects MUST support all REQUIRED operation attributes and all values of such attributes if so indicated in the description. Conforming IPP objects MUST ignore all unsupported or unknown operation attributes or operation attribute groups received in a request, but MUST reject a request that contains a supported operation attribute that contains an unsupported value.

   Conforming IPP objects MAY return operation responses that contain
   attributes groups, attributes names,  attribute syntaxes, attribute
   values, and status codes that are extensions to this standard.  The
   additional attribute groups MAY occur in any order.

The following section on object attributes specifies the support required for object attributes.

5.2.3 IPP Object Attributes

Conforming IPP objects MUST support all of the REQUIRED object attributes, as defined in this document in the indicated sections.

If an object supports an attribute, it MUST support only those values specified in this document or through the extension mechanism described in section 5.2.4. It MAY support any non-empty subset of these values. That is, it MUST support at least one of the specified values and at most all of them.

5.2.4 Versions

IPP/1.1 clients MUST meet the conformance requirements for clients specified in this document and [RFC2910]. IPP/1.1 clients MUST send requests containing a "version-number" parameter with a '1.1' value.

   IPP/1.1 Printer and Job objects MUST meet the conformance
   requirements for IPP objects specified in this document and
   [RFC2910].   IPP/1.1 objects MUST accept requests containing a
   "version-number" parameter with a '1.1' value (or reject the request
   if the operation is not supported).

It is beyond the scope of this specification to mandate conformance with previous versions. IPP/1.1 was deliberately designed, however, to make supporting previous versions easy. It is worth noting that, at the time of composing this specification (1999), we would expect IPP/1.1 Printer implementations to:

understand any valid request in the format of IPP/1.0, or 1.1;

respond appropriately with a response containing the same "version-number" parameter value used by the client in the request.

And we would expect IPP/1.1 clients to:

understand any valid response in the format of IPP/1.0, or 1.1.

It is recommended that IPP/1.1 clients try supplying alternate version numbers if they receive a 'server-error-version-not- supported' error return in a response.

5.2.5 Extensions

A conforming IPP object MAY support IETF standards track extensions and vendor extensions, as long as the extensions meet the requirements specified in Section 6.

For each attribute included in an operation response, a conforming IPP object MUST return a value whose type and value syntax conforms to the requirement of the Model document as specified in Sections 3 and 4.

5.2.6 Attribute Syntaxes

An IPP object MUST be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, in any operation in which a client may supply attributes or the system administrator may configure attributes (by means outside the scope of this IPP/1.1 document). In particular for each attribute that the IPP object supports whose attribute syntax is 'text', the IPP object MUST accept and process both the 'textWithoutLanguage' and 'textWithLanguage' forms. Similarly, for each attribute that the IPP object supports whose attribute syntax is 'name', the IPP object MUST accept and process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms. Furthermore, an IPP object MUST return attributes to the client in operation responses that conform to the syntax specified in Section 4.1, including their full range if supplied previously by a client.

5.2.7 Security

An IPP Printer implementation SHOULD contain support for Client Authentication as defined in the IPP/1.1 Encoding and Transport document [RFC2910]. A Printer implementation MAY allow an administrator to configure the Printer so that all, some, or none of the users are authenticated. See also section 8 of this document.

An IPP Printer implementation SHOULD contain support for Operation Privacy and Server Authentication as defined in the IPP/1.1 Encoding and Transport document [RFC2910]. A Printer implementation MAY allow an administrator to configure the degree of support for Operation Privacy and Server Authentication. See also section 8 of this document.

Security MUST NOT be compromised when a client supplies a lower "version-number" parameter in a request. For example, if an IPP/1.1 conforming Printer object accepts version '1.0' requests and is configured to enforce Digest Authentication, it MUST do the same for a version '1.0' request.

5.3 Charset and Natural Language Requirements

All clients and IPP objects MUST support the 'utf-8' charset as defined in section 4.1.7.

IPP objects MUST be able to accept any client request which correctly uses the "attributes-natural-language" operation attribute or the Natural Language Override mechanism on any individual attribute whether or not the natural language is supported by the IPP object. If an IPP object supports a natural language, then it MUST be able to translate (perhaps by table lookup) all generated 'text' or 'name' attribute values into one of the supported languages (see section 3.1.4). That is, the IPP object that supports a natural language NEED NOT be a general purpose translator of any arbitrary 'text' or 'name' value supplied by the client into that natural language. However, the object MUST be able to translate (automatically generate) any of its own attribute values and messages into that natural language.

6. IANA Considerations

This section describes the procedures for defining semantics for the following IETF standards track extensions and vendor extensions to the IPP/1.1 Model and Semantics document:

1. keyword attribute values
2. enum attribute values

      3. attributes
      4. attribute syntaxes
      5. operations
      6. attribute groups
      7. status codes
      8. out-of-band attribute values

Extensions registered for use with IPP/1.1 are OPTIONAL for client and IPP object conformance to the IPP/1.1 "Model and Semantics" document (this document).

These extension procedures are aligned with the guidelines as set forth by the IESG [IANA-CON]. Section 11 describes how to propose new registrations for consideration. IANA will reject registration proposals that leave out required information or do not follow the appropriate format described in Section 11. The IPP/1.1 Model and Semantics document may also be extended by an appropriate RFC that specifies any of the above extensions.

6.1 Typed 'keyword' and 'enum' Extensions

IPP allows for 'keyword' and 'enum' extensions (see sections 4.1.2.3 and 4.1.4). This document uses prefixes to the 'keyword' and 'enum' basic attribute syntax type in order to communicate extra information to the reader through its name. This extra information is not represented in the protocol because it is unimportant to a client or Printer object. The list below describes the prefixes and their meaning.

      "type1":  This IPP specification document must be revised (or
         another IETF standards track document which augments this
         document) to add a new keyword or a new enum.  No vendor
         defined keywords or enums are allowed.
      
      "type2":  Implementers can, at any time, add new keyword or enum
         values by proposing the complete specification to IANA:
      
         iana@iana.org

IANA will forward the registration proposal to the IPP Designated Expert who will review the proposal with a mailing list that the Designated Expert keeps for this purpose. Initially, that list will be the mailing list used by the IPP WG:

            ipp@pwg.org

even after the IPP WG is disbanded as permitted by [IANA-CON].

The IPP Designated Expert is appointed by the IESG Area

Director responsible for IPP, according to [IANA-CON].

When a type2 keyword or enum is approved, the IPP Designated Expert becomes the point of contact for any future maintenance that might be required for that registration.

      "type3":  Implementers can, at any time, add new keyword and enum
         values by submitting the complete specification to IANA as for
         type2 who will forward the proposal to the IPP Designated
         Expert.  While no additional technical review is required, the
         IPP Designated Expert may, at his/her discretion, forward the
         proposal to the same mailing list as for type2 registrations
         for advice and comment.

When a type3 keyword or enum is approved by the IPP Designated Expert, the original proposer becomes the point of contact for any future maintenance that might be required for that registration.

For type2 and type3 keywords, the proposer includes the name of the keyword in the registration proposal and the name is part of the technical review.

After type2 and type3 enums specifications are approved, the IPP Designated Expert in consultation with IANA assigns the next available enum number for each enum value.

IANA will publish approved type2 and type3 keyword and enum attributes value registration specifications in:

      ftp.isi.edu/iana/assignments/ipp/attribute-values/xxx/yyy.txt

where xxx is the attribute name that specifies the initial values and yyy.txt is a descriptive file name that contains one or more enums or keywords approved at the same time. For example, if several additional enums for stapling are approved for use with the "finishings" attribute (and "finishings-default" and "finishings- supported" attributes), IANA will publish the additional values in the file:

      ftp.isi.edu/iana/assignments/ipp/attribute-
      values/finishings/stapling.txt

Note: Some attributes are defined to be: 'type3 keywords' | 'name' which allows for attribute values to be extended by a site administrator with administrator defined names. Such names are not registered with IANA.

   By definition, each of the three types above assert some sort of
   registry or review process in order for extensions to be considered
   valid.  Each higher numbered level (1, 2, 3) tends to be decreasingly
   less stringent than the previous level.   Therefore, any typeN value
   MAY be registered using a process for some typeM where M is less than
   N, however such registration is NOT REQUIRED.  For example, a type3
   value MAY be registered in a type 1 manner (by being included in a
   future version of an IPP specification), however, it is NOT REQUIRED.

This document defines keyword and enum values for all of the above types, including type3 keywords.

For vendor keyword extensions, implementers SHOULD use keywords with a suitable distinguishing prefix, such as "xxx-" where xxx follows the syntax rules for keywords (see section 4.1.3) and is the (lowercase) fully qualified company name registered with IANA for use in domain names [RFC1035]. For example, if the company XYZ Corp. had obtained the domain name "XYZ.com", then a vendor keyword 'abc' would be: 'xyz.com-abc'.

   Note: RFC 1035 [RFC1035] indicates that while upper and lower case
   letters are allowed in domain names, no significance is attached to
   the case.  That is, two names with the same spelling but different
   case are to be treated as if identical.  Also, the labels in a domain
   name must follow the rules for ARPANET host names:  They must start
   with a letter, end with a letter or digit, and have as interior
   characters only letters, digits, and hyphen.  Labels must be 63
   characters or less.  Labels are separated by the "." character.

For vendor enum extensions, implementers MUST use values in the reserved integer range which is 2**30 to 2**31-1.

6.2 Attribute Extensibility

Attribute names (see section 4.1.3) are type2 keywords. Therefore, new attributes may be registered and have the same status as attributes in this document by following the type2 extension rules. For vendor attribute extensions, implementers SHOULD use keywords with a suitable distinguishing prefix as described in Section 6.1.

IANA will publish approved attribute registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/attributes/xxx-yyy.txt

where "xxx-yyy" is the new attribute name.

If a new Printer object attribute is defined and its values can be affected by a specific document format, its specification needs to contain the following sentence:

"The value of this attribute returned in a Get-Printer-

Attributes response MAY depend on the "document-format"

attribute supplied (see Section 3.2.5.1)."

If the specification does not, then its value in the Get-Printer- Attributes response MUST NOT depend on the "document-format" supplied in the request. When a new Job Template attribute is registered, the value of the Printer attributes MAY vary with "document-format" supplied in the request without the specification having to indicate so.

6.3 Attribute Syntax Extensibility

Attribute syntaxes (see section 4.1) are like type2 enums. Therefore, new attribute syntaxes may be registered and have the same status as attribute syntaxes in this document by following the type2 extension rules described in Section 6.1. The initial set of value codes that identify each of the attribute syntaxes have been assigned in the "Encoding and Transport" document [RFC2910], including a designated range for vendor extension.

For attribute syntaxes, the IPP Designated Expert in consultation with IANA assigns the next attribute syntax code in the appropriate range as specified in [RFC2910]. IANA will publish approved attribute syntax registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/attribute-syntaxes/xxx-yyy.txt

where 'xxx-yyy' is the new attribute syntax name.

6.4 Operation Extensibility

Operations (see section 3) may also be registered following the type2 procedures described in Section 6.1, though major new operations will usually be done by a new standards track RFC that augments this document. For vendor operation extensions, implementers MUST use the range for the "operation-id" in requests specified in Section 4.4.15 "operations-supported" Printer attribute.

For operations, the IPP Designated Expert in consultation with IANA assigns the next operation-id code as specified in Section 4.4.15. IANA will publish approved operation registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/operations/Xxx-Yyy.txt

where "Xxx-Yyy" is the new operation name.

6.5 Attribute Group Extensibility

Attribute groups (see section 3.1.3) passed in requests and responses may be registered following the type2 procedures described in Section 6.1. The initial set of attribute group tags have been assigned in the "Encoding and Transport" document [RFC2910], including a designated range for vendor extension.

For attribute groups, the IPP Designated Expert in consultation with IANA assigns the next attribute group tag code in the appropriate range as specified in [RFC2910]. IANA will publish approved attribute group registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/attribute-group-tags/xxx-yyy-
      tag.txt

where 'xxx-yyy-tag' is the new attribute group tag name.

6.6 Status Code Extensibility

Operation status codes (see section 3.1.6.1) may also be registered following the type2 procedures described in Section 6.1. The values for status codes are allocated in ranges as specified in Section 14 for each status code class:

      "informational" - Request received, continuing process
      "successful" - The action was successfully received, understood, and
         accepted
      "redirection" - Further action must be taken in order to complete the
         request
      "client-error" - The request contains bad syntax or cannot be
         fulfilled
      "server-error" - The IPP object  failed to fulfill an apparently
         valid request

For vendor operation status code extensions, implementers MUST use the top of each range as specified in Section 13.

For operation status codes, the IPP Designated Expert in consultation with IANA assigns the next status code in the appropriate class range as specified in Section 13. IANA will publish approved status code registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/status-codes/xxx-yyy.txt

where "xxx-yyy" is the new operation status code keyword.

6.7 Out-of-band Attribute Value Extensibility

Out-of-band attribute values (see the beginning of section 4.1) passed in requests and responses may be registered following the type2 procedures described in Section 6.1. The initial set of out- of-band attribute value tags have been assigned in the "Encoding and Transport" document [RFC2910].

For out-of-band attribute value tags, the IPP Designated Expert in consultation with IANA assigns the next out-of-band attribute value tag code in the appropriate range as specified in [RFC2910]. IANA will publish approved out-of-band attribute value tags registration specifications as separate files:

      ftp.isi.edu/iana/assignments/ipp/out-of-band-attribute-value-
      tags/xxx-yyy-tag.txt

where 'xxx-yyy-tag' is the new out-of-band attribute value tag name.

6.8 Registration of MIME types/sub-types for document-formats

The "document-format" attribute's syntax is 'mimeMediaType'. This means that valid values are Internet Media Types (see Section 4.1.9). RFC 2045 [RFC2045] defines the syntax for valid Internet media types. IANA is the registry for all Internet media types.

6.9 Registration of charsets for use in 'charset' attribute values

The "attributes-charset" attribute's syntax is 'charset'. This means that valid values are charsets names. When a charset in the IANA registry has more than one name (alias), the name labeled as "(preferred MIME name)", if present, MUST be used (see Section 4.1.7). IANA is the registry for charsets following the procedures of [RFC2278].

7. Internationalization Considerations

Some of the attributes have values that are text strings and names which are intended for human understanding rather than machine understanding (see the 'text' and 'name' attribute syntaxes in Sections 4.1.1 and 4.1.2).

In each operation request, the client

identifies the charset and natural language of the request which affects each supplied 'text' and 'name' attribute value, and

requests the charset and natural language for attributes returned by the IPP object in operation responses (as described in Section 3.1.4.1).

In addition, the client MAY separately and individually identify the Natural Language Override of a supplied 'text' or 'name' attribute using the 'textWithLanguage' and 'nameWithLanguage' technique described section 4.1.1.2 and 4.1.2.2 respectively.

All IPP objects MUST support the UTF-8 [RFC2279] charset in all 'text' and 'name' attributes supported. If an IPP object supports more than the UTF-8 charset, the object MUST convert between them in order to return the requested charset to the client according to Section 3.1.4.2. If an IPP object supports more than one natural language, the object SHOULD return 'text' and 'name' values in the natural language requested where those values are generated by the Printer (see Section 3.1.4.1).

For Printers that support multiple charsets and/or multiple natural languages in 'text' and 'name' attributes, different jobs may have been submitted in differing charsets and/or natural languages. All responses MUST be returned in the charset requested by the client. However, the Get-Jobs operation uses the 'textWithLanguage' and 'nameWithLanguage' mechanism to identify the differing natural languages with each job attribute returned.

   The Printer object also has configured charset and natural language
   attributes.   The client can query the Printer object to determine
   the list of charsets and natural languages supported by the Printer
   object and what the Printer object's configured values are.  See the
   "charset-configured", "charset-supported", "natural-language-
   configured", and "generated-natural-language-supported" Printer
   description attributes for more details.

The "charset-supported" attributed identifies the supported charsets. If a charset is supported, the IPP object MUST be capable of converting to and from that charset into any other supported charset. In many cases, an IPP object will support only one charset and it MUST be the UTF-8 charset.

The "charset-configured" attribute identifies the one supported charset which is the native charset given the current configuration of the IPP object (administrator defined).

The "generated-natural-language-supported" attribute identifies the set of supported natural languages for generated messages; it is not related to the set of natural languages that must be accepted for client supplied 'text' and 'name' attributes. For client supplied

'text' and 'name' attributes, an IPP object MUST accept ALL supplied natural languages. Just because a Printer object is currently configured to support 'en-us' natural language does not mean that the Printer object should reject a job if the client supplies a job name that is in 'fr-ca'.

The "natural-language-configured" attribute identifies the one supported natural language for generated messages which is the native natural language given the current configuration of the IPP object (administrator defined).

Attributes of type 'text' and 'name' are populated from different sources. These attributes can be categorized into following groups (depending on the source of the attribute):

      1. Some attributes are supplied by the client (e.g., the client
         supplied "job-name", "document-name", and "requesting-user-
         name" operation attributes along with the corresponding Job
         object's "job-name" and "job-originating-user-name"
         attributes).  The IPP object MUST accept these attributes in
         any natural language no matter what the set of supported
         languages for generated messages
      2. Some attributes are supplied by the system administrator (e.g.,
         the Printer object's "printer-name" and "printer-location"
         attributes).  These too can be in any natural language.  If the
         natural language for these attributes is different than what a
         client requests, then they must be reported using the Natural
         Language Override mechanism.
      3. Some attributes are supplied by the device manufacturer (e.g.,
         the Printer object's "printer-make-and-model" attribute).
         These too can be in any natural language.  If the natural
         language for these attributes is different than what a client
         requests, then they must be reported using the Natural Language
         Override mechanism.
      4. Some attributes are supplied by the operator (e.g., the Job
         object's "job-message-from-operator" attribute). These too can
         be in any natural language.  If the natural language for these
         attributes is different than what a client requests, then they
         must be reported using the Natural Language Override mechanism.
      5. Some attributes are generated by the IPP object (e.g., the Job
         object's "job-state-message" attribute, the Printer object's
         "printer-state-message" attribute, and the "status-message"
         operation attribute).  These attributes can only be in one of
         the "generated-natural-language-supported" natural languages.
         If a client requests some natural language for these attributes
         other than one of the supported values, the IPP object SHOULD

respond using the value of the "natural-language-configured"

attribute (using the Natural Language Override mechanism if

needed).

The 'text' and 'name' attributes specified in this version of this document (additional ones will be registered according to the procedures in Section 6) are:

                    Attributes                            Source

Operation Attributes:

        job-name (name)                         client
        document-name (name)                    client
        requesting-user-name (name)             client
        status-message (text)                   Job or Printer object
        detailed-status-message (text)          Job or Printer object -
                                                see rule 1
        document-access-error (text)            Job or Printer object -
                                                see rule 1

Job Template Attributes:

        job-hold-until (keyword | name)         client matches
                                                administrator-configured
        job-hold-until-default (keyword | name) client matches
                                                administrator-configured
        job-hold-until-supported (keyword |     client matches
        name)                                   administrator-configured
        job-sheets (keyword | name)             client matches
                                                administrator-configured
        job-sheets-default (keyword | name)     client matches
                                                administrator-configured
        job-sheets-supported (keyword | name)   client matches
                                                administrator-configured
        media (keyword | name)                  client matches
                                                administrator-configured
        media-default (keyword | name)          client matches
                                                administrator-configured
        media-supported (keyword | name)        client matches
                                                administrator-configured
        media-ready (keyword | name)            client matches
                                                administrator-configured

Job Description Attributes:

        job-name (name)                         client or Printer object
        job-originating-user-name (name)        Printer object
        job-state-message (text)                Job or Printer object
        output-device-assigned (name(127))      administrator
        job-message-from-operator (text(127))   operator
        
        job-detailed-status-messages (1setOf    Job or Printer object -
        text)                                   see rule 1
        job-document-access-errors (1setOf      Job or Printer object -
        text)                                   see rule 1

Printer Description Attributes:

        printer-name (name(127))                administrator
        printer-location (text(127))            administrator
        printer-info (text(127))                administrator
        printer-make-and-model (text(127))      administrator or
                                                manufacturer
        printer-state-message (text)            Printer object
        printer-message-from-operator           operator
        (text(127))

Rule 1 - Neither the Printer nor the client localizes these message attributes, since they are intended for use by the system administrator or other experienced technical persons.

8. Security Considerations

It is difficult to anticipate the security risks that might exist in any given IPP environment. For example, if IPP is used within a given corporation over a private network, the risks of exposing document data may be low enough that the corporation will choose not to use encryption on that data. However, if the connection between the client and the IPP object is over a public network, the client may wish to protect the content of the information during transmission through the network with encryption.

Furthermore, the value of the information being printed may vary from one IPP environment to the next. Printing payroll checks, for example, would have a different value than printing public information from a file. There is also the possibly of denial-of- service attacks, but denial-of-service attacks against printing resources are not well understood and there is no published precedents regarding this scenario.

Once the authenticated identity of the requester has been supplied to the IPP object, the object uses that identity to enforce any authorization policy that might be in place. For example, one site's policy might be that only the job owner is allowed to cancel a job. The details and mechanisms to set up a particular access control policy are not part of IPP/1.1, and must be established via some other type of administrative or access control framework. However, there are operation status codes that allow an IPP server to return information back to a client about any potential access control violations for an IPP object.

During a create operation, the client's identity is recorded in the Job object in an implementation-defined attribute. This information can be used to verify a client's identity for subsequent operations on that Job object in order to enforce any access control policy that might be in effect. See section 8.3 below for more details.

Since the security levels or the specific threats that an IPP system administrator may be concerned with cannot be anticipated, IPP MUST be capable of operating with different security mechanisms and security policies as required by the individual installation. Security policies might vary from very strong, to very weak, to none at all, and corresponding security mechanisms will be required.

8.1 Security Scenarios

The following sections describe specific security attacks for IPP environments. Where examples are provided they should be considered illustrative of the environment and not an exhaustive set. Not all of these environments will necessarily be addressed in initial implementations of IPP.

8.1.1 Client and Server in the Same Security Domain

This environment is typical of internal networks where traditional office workers print the output of personal productivity applications on shared work-group printers, or where batch applications print their output on large production printers. Although the identity of the user may be trusted in this environment, a user might want to protect the content of a document against such attacks as eavesdropping, replaying or tampering.

8.1.2 Client and Server in Different Security Domains

Examples of this environment include printing a document created by the client on a publicly available printer, such as at a commercial print shop; or printing a document remotely on a business associate's printer. This latter operation is functionally equivalent to sending the document to the business associate as a facsimile. Printing sensitive information on a Printer in a different security domain requires strong security measures. In this environment authentication of the printer is required as well as protection against unauthorized use of print resources. Since the document crosses security domains, protection against eavesdropping and document tampering are also required. It will also be important in this environment to protect Printers against "spamming" and malicious document content.

8.1.3 Print by Reference

When the document is not stored on the client, printing can be done by reference. That is, the print request can contain a reference, or pointer, to the document instead of the actual document itself (see sections 3.2.2 and 3.3.2). Standard methods currently do not exist for remote entities to "assume" the credentials of a client for forwarding requests to a 3rd party. It is anticipated that Print-By- Reference will be used to access "public" documents and that sophisticated methods for authenticating "proxies" is not specified in this document.

8.2 URIs in Operation, Job, and Printer attributes

The "printer-uri-supported" attribute contains the Printer object's URI(s). Its companion attribute, "uri-security-supported", identifies the security mechanism used for each URI listed in the "printer-uri-supported" attribute. For each Printer operation request, a client MUST supply only one URI in the "printer-uri" operation attribute. In other words, even though the Printer supports more than one URI, the client only interacts with the Printer object using one if its URIs. This duality is not needed for Job objects, since the Printer objects is the factory for Job objects, and the Printer object will generate the correct URI for new Job objects depending on the Printer object's security configuration.

8.3 URIs for each authentication mechanisms

Each URI has an authentication mechanism associated with it. If the URI is the i'th element of "printer-uri-supported", then authentication mechanism is the "i th" element of "uri- authentication-supported". For a list of possible authentication mechanisms, see section 4.4.2.

The Printer object uses an authentication mechanism to determine the name of the user performing an operation. This user is called the "authenticated user". The credibility of authentication depends on the mechanism that the Printer uses to obtain the user's name. When the authentication mechanism is 'none', all authenticated users are "anonymous".

During job creation operations, the Printer initializes the value of the "job-originating-user-name" attribute (see section 4.3.6) to be the authenticated user. The authenticated user is this case is called the "job owner".

If an implementation can be configured to support more than one authentication mechanism (see section 4.4.2), then it MUST implement rules for determining equality of authenticated user names which have been authenticated via different authentication mechanisms. One possible policy is that identical names that are authenticated via different mechanisms are different. For example, a user can cancel his job only if he uses the same authentication mechanism for both Cancel-Job and Print-Job. Another policy is that identical names that are authenticated via different mechanism are the same if the authentication mechanism for the later operation is not less strong than the authentication mechanism for the earlier job creation operation. For example, a user can cancel his job only if he uses the same or stronger authentication mechanism for Cancel-Job and Print-Job. With this second policy a job submitted via 'requesting- user-name' authentication could be canceled via 'digest' authentication. With the first policy, the job could not be canceled in this way.

A client is able to determine the authentication mechanism used to create a job. It is the i'th value of the Printer's "uri- authentication-supported" attribute (see section 4.4.2), where i is the index of the element of the Printer's "printer-uri-supported" attribute (see section 4.4.1) equal to the job's "job-printer-uri" attribute (see section 4.3.3).

8.4 Restricted Queries

In many IPP operations, a client supplies a list of attributes to be returned in the response. For security reasons, an IPP object may be configured not to return all attributes (or all values) that a client requests. The job attributes returned MAY depend on whether the requesting user is the same as the user that submitted the job. The IPP object MAY even return none of the requested attributes. In such cases, the status returned is the same as if the object had returned all requested attributes. The client cannot tell by such a response whether the requested attribute was present or absent on the object.

8.5 Operations performed by operators and system administrators

   For the three printer operations Pause-Printer, Resume-Printer, and
   Purge-Jobs (see sections 3.2.7, 3.2.8 and 3.2.9), the requesting user
   is intended to be an operator or administrator of the Printer object
   (see section 1).  Otherwise, the IPP Printer MUST reject the
   operation and return:  'client-error-forbidden', 'client-error-not-
   authenticated', or 'client-error-not-authorized' as appropriate.  For
   operations on jobs, the requesting user is intended to be the job

owner or may be an operator or administrator of the Printer object. The means for authorizing an operator or administrator of the Printer object are not specified in this document.

8.6 Queries on jobs submitted using non-IPP protocols

If the device that an IPP Printer is representing is able to accept jobs using other job submission protocols in addition to IPP, it is RECOMMENDED that such an implementation at least allow such "foreign" jobs to be queried using Get-Jobs returning "job-id" and "job-uri" as 'unknown'. Such an implementation NEED NOT support all of the same IPP job attributes as for IPP jobs. The IPP object returns the 'unknown' out-of-band value for any requested attribute of a foreign job that is supported for IPP jobs, but not for foreign jobs.

It is further RECOMMENDED, that the IPP Printer generate "job-id" and "job-uri" values for such "foreign jobs", if possible, so that they may be targets of other IPP operations, such as Get-Job-Attributes and Cancel-Job. Such an implementation also needs to deal with the problem of authentication of such foreign jobs. One approach would be to treat all such foreign jobs as belonging to users other than the user of the IPP client. Another approach would be for the foreign job to belong to 'anonymous'. Only if the IPP client has been authenticated as an operator or administrator of the IPP Printer object, could the foreign jobs be queried by an IPP request. Alternatively, if the security policy is to allow users to query other users' jobs, then the foreign jobs would also be visible to an end-user IPP client using Get-Jobs and Get-Job-Attributes.

9. References

[ASME-Y14.1M] Metric Drawing Sheet Size and Format, ASME Y14.1M-1995.

This standard defines metric sheet sizes and formats for engineering drawings.

   [ASCII]       Coded Character Set - 7-bit American Standard Code for
                 Information Interchange (ASCII), ANSI X3.4-1986. This
                 standard is the specification of the US-ASCII charset.
   
   [BCP-11]      Bradner S. and R. Hovey, "The Organizations Involved in
                 the IETF Standards Process", BCP 11, RFC 2028, October
                 1996.
   
   [HTPP]        J. Barnett, K. Carter, R. DeBry,  "Initial Draft -
                 Hypertext Printing Protocol - HTPP/1.0", October 1996,
              ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/overview.ps.gz
   
   [IANA-CON]    Narten, T. and H. Alvestrand, "Guidelines for Writing
                 an IANA Considerations Section in RFCs", BCP 26, RFC
                 2434, October 1998.
   
   [IANA-CS]     IANA Registry of Coded Character Sets:
                 ftp://ftp.isi.edu/in-notes/iana/assignments/character-
                 sets
   
   [IANA-MT]     IANA Registry of Media Types:  ftp://ftp.isi.edu/in-
                 notes/iana/assignments/media-types/
   
   [IPP-IIG]     Hastings, T., Manros, C., Kugler, C., Holst, H., and P.
                 Zehler, "Internet Printing Protocol/1.1:  draft-ietf-
                 ipp-implementers-guide-v11-01.txt, work in progress,
                 May 30, 2000.
   
   [ISO10646-1]  ISO/IEC 10646-1:1993, "Information technology --
                 Universal Multiple-Octet Coded Character Set (UCS) -
                 Part 1: Architecture and Basic Multilingual Plane,
                 JTC1/SC2."
   
   [ISO8859-1]   ISO/IEC 8859-1:1987, "Information technology -- 8-bit
                 One-Byte Coded Character Set - Part 1: Latin Alphabet
                 Nr 1", 1987, JTC1/SC2.
   
   [ISO10175]    ISO/IEC 10175 Document Printing Application (DPA), June
                 1996.
   
   [LDPA]        T. Hastings,  S. Isaacson,  M. MacKay, C. Manros, D.
                 Taylor, P. Zehler,  "LDPA - Lightweight Document
                 Printing Application", October 1996,
              ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/ldpa8.pdf.gz
   
   [P1387.4]     Kirk, M. (editor), POSIX System Administration - Part
                 4:  Printing Interfaces, POSIX 1387.4 D8, 1994.
   
   [PSIS]        Herriot, R. (editor), X/Open A Printing System
                 Interoperability Specification (PSIS), August 1995.
   
   [PWG]         Printer Working Group, http://www.pwg.org.
   
   [RFC1035]     Mockapetris, P., "Domain Names - Implementation and
                 Specification", STD 13, RFC 1035, November 1987.
   
   [RFC1179]     McLaughlin, L., "Line Printer Daemon Protocol", RFC
                 1179, August 1990.
   
   [RFC1759]     Smith, R., Wright, F., Hastings, T., Zilles, S. and J.
                 Gyllenskog, "Printer MIB", RFC 1759, March 1995.
   
   [RFC1766]     Alvestrand, H., "Tags for the Identification of
                 Languages", RFC 1766, March 1995.
   
   [RFC1951]     Deutsch, P., "DEFLATE Compressed Data Format
                 Specification version 1.3 ", RFC 1951, May 1996.
   
   [RFC1952]     Deutsch, P., "GZIP file format specification version
                 4.3", RFC 1952, May 1996.
   
   [RFC1977]     Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
                 August 1996.
   
   [RFC2026]     Bradner, S., "The Internet Standards Process --
                 Revision 3", BCP 9, RFC 2026, October 1996.
   
   [RFC2045]     Freed, N. and  N. Borenstein, ", Multipurpose Internet
                 Mail Extensions (MIME) Part One: Format of Internet
                 Message Bodies", RFC 2045, November 1996.
   
   [RFC2046]     Freed, N. and N. Borenstein, "Multipurpose Internet
                 Mail Extensions (MIME) Part Two: Media Types", RFC
                 2046, November 1996.
   
   [RFC2048]     Freed, N., Klensin, J. and J. Postel, "Multipurpose
                 Internet Mail Extension (MIME) Part Four: Registration
                 Procedures", RFC 2048, November 1996.
   
   [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.
   
   [RFC2228]     Horowitz, M. and S. Lunt, "FTP Security Extensions",
                 RFC 2228, October 1997.
   
   [RFC2246]     Dierks, T. and C. Allen, "The TLS Protocol Version
                 1.0", RFC 2246, January 1999.
   
   [RFC2277]     Alvestrand, H., "IETF Policy on Character Sets and
                 Languages" BCP 18, RFC 2277, January 1998.
   
   [RFC2278]     Freed, N. and J. Postel: "IANA CharSet Registration
                 Procedures", BCP 19, RFC 2278, January 1998.
   
   [RFC2279]     Yergeau, F., "UTF-8, a transformation format of ISO
                 10646", RFC 2279, January 1998.
   
   [RFC2316]     Bellovin, S., "Report of the IAB Security Architecture
                 Workshop", RFC 2316, April 1998.
   
   [RFC2396]     Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
                 Resource Identifiers (URI): Generic Syntax", RFC 2396,
                 August 1998.
   
   [RFC2565]     Herriot, R., Butler, S., Moore, P. and R. Turner,
                 "Internet Printing Protocol/1.0: Encoding and
                 Transport", RFC 2565, April 1999.
   
   [RFC2566]     deBry, R., Hastings, T., Herriot, R., Isaacson, S. and
                 P. Powell, "Internet Printing Protocol/1.0: Model and
                 Semantics", RFC 2566, April 1999.
   
   [RFC2567]     Wright, D., "Design Goals for an Internet Printing
                 Protocol", RFC 2567, April 1999.
   
   [RFC2568]     Zilles, S., "Rationale for the Structure and Model and
                 Protocol for the Internet Printing Protocol", RFC 2568,
                 April 1999.
   
   [RFC2569]     Herriot, R., Hastings, T., Jacobs, N. and J. Martin,
                 "Mapping between LPD and IPP Protocols", RFC 2569,
                 April 1999.
   
   [RFC2579]     McCloghrie, K., Perkins, D. and J. Schoenwaelder,
                 "Textual Conventions for SMIv2", STD 58, RFC 2579,
                 April 1999.
   
   [RFC2616]     Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
                 Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
                 Transfer Protocol - HTTP/1.1", RFC 2616, June 1999.
   
   [RFC2617]     Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence,
                 S., Leach, P., Luotonen, A. and L. Stewart, "HTTP
                 Authentication:  Basic and Digest Access
                 Authentication", RFC 2617, June 1999.
   
   [RFC2639]     Hastings, T. and C. Manros, "Internet Printing
                 Protocol/1.0: Encoding and Transport", RFC 2639, July
                 1999.
   
   [RFC2910]     Herriot, R., Butler, S., Moore, P., Turner, R. and J.
                 Wenn, "Internet Printing Protocol/1.1: Encoding and
                 Transport", RFC 2910, September 2000.
   
   [SSL]         Netscape, The SSL Protocol, Version 3, (Text version
                 3.02), November 1996.
   
   [SWP]         P. Moore, B. Jahromi, S. Butler, "Simple Web Printing
                 SWP/1.0", May 7, 1997,
                 ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/swp9705.pdf

10. Authors' Addresses

   Scott A. Isaacson, Editor
   Novell, Inc.
   122 E 1700 S
   Provo, UT   84606
   
   Phone: 801-861-7366
   Fax:   801-861-2517
   EMail: sisaacson@novell.com
   
   Tom Hastings
   Xerox Corporation
   737 Hawaii St.  ESAE 231
   El Segundo, CA   90245
   
   Phone: 310-333-6413
   Fax:   310-333-5514
   EMail: hastings@cp10.es.xerox.com

Robert Herriot
Xerox Corp.
3400 Hill View Ave, Building 1
Palo Alto, CA 94304

   Phone: 650-813-7696
   Fax:  650-813-6860
   EMail: robert.herriot@pahv.xerox.com

Roger deBry
Utah Valley State College
Orem, UT 84058

   Phone: (801) 222-8000
   EMail: debryro@uvsc.edu
   Patrick Powell
   Astart Technologies
   9475 Chesapeake Dr., Suite D
   San Diego, CA  95123
   
   Phone: (619) 874-6543
   Fax:   (619) 279-8424
   EMail: papowell@astart.com
   
   IPP Web Page:  http://www.pwg.org/ipp/
   IPP Mailing List:  ipp@pwg.org

To subscribe to the ipp mailing list, send the following email:

1) send it to majordomo@pwg.org
2) leave the subject line blank
3) put the following two lines in the message body:

subscribe ipp
end

Implementers of this specification document are encouraged to join IPP Mailing List in order to participate in any discussions of clarification issues and review of registration proposals for additional attributes and values.

Other Participants:

   Chuck Adams - Tektronix             Shivaun Albright - HP
   Stefan Andersson - Axis             Jeff Barnett - IBM
   Ron Bergman - Hitachi Koki Imaging  Dennis Carney - IBM
   Systems
   Keith Carter - IBM                  Angelo Caruso - Xerox
   Rajesh Chawla - TR Computing        Nancy Chen - Okidata
   Solutions
   Josh Cohen - Microsoft              Jeff Copeland - QMS
   Andy Davidson - Tektronix           Roger deBry - IBM
   Maulik Desai - Auco                 Mabry Dozier - QMS
   Lee Farrell - Canon Information     Satoshi Fujitami - Ricoh
   Systems
   Steve Gebert - IBM                  Sue Gleeson - Digital
   Charles Gordon - Osicom             Brian Grimshaw - Apple
   Jerry Hadsell - IBM                 Richard Hart - Digital
   Tom Hastings - Xerox                Henrik Holst - I-data
   Stephen Holmstead                   Zhi-Hong Huang - Zenographics
   Scott Isaacson - Novell             Babek Jahromi - Microsoft
   Swen Johnson - Xerox                David Kellerman - Northlake
                                       Software
   Robert Kline - TrueSpectra          Charles Kong - Panasonic
   Carl Kugler - IBM                   Dave Kuntz - Hewlett-Packard
   Takami Kurono - Brother             Rick Landau - Digital
   Scott Lawrence - Agranot Systems    Greg LeClair - Epson
   Dwight Lewis - Lexmark              Harry Lewis - IBM
   Tony Liao - Vivid Image             Roy Lomicka - Digital
   Pete Loya - HP                      Ray Lutz - Cognisys
   Mike MacKay - Novell, Inc.          David Manchala - Xerox
   Carl-Uno Manros - Xerox             Jay Martin - Underscore
   Stan McConnell - Xerox              Larry Masinter - Xerox
   Sandra Matts - Hewlett Packard      Peter Michalek - Shinesoft
   Ira McDonald - High North Inc.      Mike Moldovan - G3 Nova
   Tetsuya Morita - Ricoh              Yuichi Niwa - Ricoh
   Pat Nogay - IBM                     Ron Norton - Printronics
   Hugo Parra, Novell                  Bob Pentecost - Hewlett-Packard
   Patrick Powell - Astart             Jeff Rackowitz - Intermec
   Technologies
   Eric Random - Peerless              Rob Rhoads - Intel
   Xavier Riley - Xerox                Gary Roberts - Ricoh
   David Roach - Unisys                Stuart Rowley - Kyocera
   Yuji Sasaki - Japan Computer        Richard Schneider - Epson
   Industry
   Kris Schoff - HP                    Katsuaki Sekiguchi - Canon
   Bob Setterbo - Adobe                Gail Songer - Peerless
   Hideki Tanaka - Cannon              Devon Taylor - Novell
   Mike Timperman - Lexmark            Atsushi Uchino - Epson
   Shigeru Ueda - Canon                Bob Von Andel - Allegro Software
   William Wagner - NetSilicon/DPI     Jim Walker - DAZEL
   Chris Wellens - Interworking Labs   Trevor Wells - Hewlett Packard
   Craig Whittle - Sharp Labs          Rob Whittle - Novell, Inc.
   Jasper Wong - Xionics               Don Wright - Lexmark
   Michael Wu - Heidelberg Digital     Rick Yardumian - Xerox
   Michael Yeung - Toshiba             Lloyd Young - Lexmark
   Atsushi Yuki - Kyocera              Peter Zehler - Xerox
   William Zhang- Canon Information    Frank Zhao - Panasonic
   Systems
   Steve Zilles - Adobe                Rob Zirnstein - Canon Information
                                       Systems

11. Formats for IPP Registration Proposals

In order to propose an IPP extension for registration, the proposer must submit an application to IANA by email to "iana@iana.org" or by filling out the appropriate form on the IANA web pages (http://www.iana.org). This section specifies the required information and the formats for proposing registrations of extensions to IPP as provided in Section 6 for:

1. type2 'keyword' attribute values
2. type3 'keyword' attribute values
3. type2 'enum' attribute values
4. type3 'enum' attribute values
5. attributes
6. attribute syntaxes
7. operations
8. status codes
9. out-of-band attribute values

11.1 Type2 keyword attribute values registration,

   Type of registration:  type2 keyword attribute value
   Name of attribute to which this keyword specification is to be added:
   Proposed keyword name of this keyword value:
   Specification of this keyword value (follow the style of IPP Model
   Section 4.1.2.3):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For type2 keywords, the Designated Expert will be the point of
   contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.2 Type3 keyword attribute values registration

   Type of registration:  type3 keyword attribute value
   Name of attribute to which this keyword specification is to be added:
   Proposed keyword name of this keyword value:
   Specification of this keyword value (follow the style of IPP Model
   Section 4.1.2.3):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For type3 keywords, the proposer will be the point of contact
   for the approved registration specification, if any maintenance of
   the registration specification is needed.

11.3 Type2 enum attribute values registration

   Type of registration:  type2 enum attribute value
   Name of attribute to which this enum specification is to be added:
   Keyword symbolic name of this enum value:
   Numeric value (to be assigned by the IPP Designated Expert in
   consultation with IANA):

Specification of this enum value (follow the style of IPP Model Section 4.1.4):
Name of proposer:
Address of proposer:
Email address of proposer:

   Note:  For type2 enums, the Designated Expert will be the point of
   contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.4 Type3 enum attribute values registration

   Type of registration:  type3 enum attribute value
   Name of attribute to which this enum specification is to be added:
   Keyword symbolic name of this enum value:
   Numeric value (to be assigned by the IPP Designated Expert in
   consultation with IANA):
   Specification of this enum value (follow the style of IPP Model
   Section 4.1.4):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For type3 enums, the proposer will be the point of contact for
   the approved registration specification, if any maintenance of the
   registration specification is needed.

11.5 Attribute registration

   Type of registration:  attribute
   Proposed keyword name of this attribute:
   Types of attribute (Operation, Job Template, Job Description, Printer
   Description):
   Operations to be used with if the attribute is an operation attribute:
   Object (Job, Printer, etc. if bound to an object):
   Attribute syntax(es) (include 1setOf and range as in Section 4.2):
   If attribute syntax is 'keyword' or 'enum', is it type2 or type3:
   If this is a Printer attribute, MAY the value returned depend on
   "document-format" (See Section 6.2):
   If this is a Job Template attribute, how does its specification depend
   on the value of the "multiple-document-handling" attribute:
   Specification of this attribute (follow the style of IPP Model Section
   4.2):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   Note:  For attributes, the IPP Designated Expert will be the point of
   contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.6 Attribute Syntax registration

   Type of registration:  attribute syntax
   Proposed name of this attribute syntax:
   Type of attribute syntax (integer, octetString, character-string,  see
   [RFC2910]):
   Numeric tag according to [RFC2910] (to be assigned by the IPP
   Designated Expert in consultation with IANA):
   Specification of this attribute (follow the style of IPP Model Section
   4.1):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For attribute syntaxes, the IPP Designated Expert will be the
   point of contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.7 Operation registration

   Type of registration:  operation
   Proposed name of this operation:
   Numeric operation-id value according to section 4.4.15 (to be assigned
   by the IPP Designated Expert in consultation with IANA):
   Object Target (Job, Printer, etc. that operation is upon):
   Specification of this operation (follow the style of IPP Model Section
   3):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For operations, the IPP Designated Expert will be the point of
   contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.8 Attribute Group registration

   Type of registration:  attribute group
   Proposed name of this attribute group:
   Numeric tag according to [RFC2910] (to be assigned by the IPP
   Designated Expert in consultation with IANA):
   Operation requests and group number for each operation in which the
   attribute group occurs:

Operation responses and group number for each operation in which the attribute group occurs:
Specification of this attribute group (follow the style of IPP Model Section 3):
Name of proposer:
Address of proposer:
Email address of proposer:

   Note:  For attribute groups, the IPP Designated Expert will be the
   point of contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.9 Status code registration

   Type of registration:  status code
   Keyword symbolic name of this status code value:
   Numeric value (to be assigned by the IPP Designated Expert in
   consultation with IANA):
   Operations that this status code may be used with:
   Specification of this status code (follow the style of IPP Model
   Section 13 APPENDIX B:  Status Codes and Suggested Status Code
   Messages):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For status codes, the Designated Expert will be the point of
   contact for the approved registration specification, if any
   maintenance of the registration specification is needed.

11.10 Out-of-band Attribute Value registration

   Type of registration:  out-of-band attribute value
   Proposed name of this out-of-band attribute value:
   Numeric tag according to [RFC2910] (to be assigned by the IPP Designated
   Expert in consultation with IANA):
   Operations that this out-of-band attribute value may be used with:
   Attributes that this out-of-band attribute value may be used with:
   Specification of this out-of-band attribute value (follow the style of
   the beginning of IPP Model Section 4.1):
   Name of proposer:
   Address of proposer:
   Email address of proposer:
   
   Note:  For out-of-band attribute values, the IPP Designated Expert
   will be the point of contact for the approved registration
   specification, if any maintenance of the registration specification
   is needed.

12. APPENDIX A: Terminology

This specification document uses the terminology defined in this section.

12.1 Conformance Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and  "OPTIONAL" in this document are to be
   interpreted as described in RFC 2119 [RFC2119].

12.1.1 NEED NOT

This term is not included in RFC 2119. The verb "NEED NOT" indicates an action that the subject of the sentence does not have to implement in order to claim conformance to the standard. The verb "NEED NOT" is used instead of "MAY NOT" since "MAY NOT" sounds like a prohibition.

12.2 Model Terminology

12.2.1 Keyword

Keywords are used within this document as identifiers of semantic entities within the abstract model (see section 4.1.2.3). Attribute names, some attribute values, attribute syntaxes, and attribute group names are represented as keywords.

12.2.2 Attributes

An attribute is an item of information that is associated with an instance of an IPP object. An attribute consists of an attribute name and one or more attribute values. Each attribute has a specific attribute syntax. All object attributes are defined in section 4 and all operation attributes are defined in section 3.

Job Template Attributes are described in section 4.2. The client optionally supplies Job Template attributes in a create request (operation requests that create Job objects). The Printer object has associated attributes which define supported and default values for the Printer.

12.2.2.1 Attribute Name

Each attribute is uniquely identified in this document by its attribute name. An attribute name is a keyword. The keyword attribute name is given in the section header describing that attribute. In running text in this document, attribute names are indicated inside double quotation marks (") where the quotation marks are not part of the keyword itself.

12.2.2.2 Attribute Group Name

Related attributes are grouped into named groups. The name of the group is a keyword. The group name may be used in place of naming all the attributes in the group explicitly. Attribute groups are defined in section 3.

12.2.2.3 Attribute Value

Each attribute has one or more values. Attribute values are represented in the syntax type specified for that attribute. In running text in this document, attribute values are indicated inside single quotation marks ('), whether their attribute syntax is keyword, integer, text, etc. where the quotation marks are not part of the value itself.

12.2.2.4 Attribute Syntax

Each attribute is defined using an explicit syntax type. In this document, each syntax type is defined as a keyword with specific meaning. The "Encoding and Transport" document [RFC2910] indicates the actual "on-the-wire" encoding rules for each syntax type. Attribute syntax types are defined in section 4.1.

12.2.3 Supports

By definition, a Printer object supports an attribute only if that Printer object responds with the corresponding attribute populated with some value(s) in a response to a query for that attribute. A Printer object supports an attribute value if the value is one of the Printer object's "supported values" attributes. The device behind a Printer object may exhibit a behavior that corresponds to some IPP attribute, but if the Printer object, when queried for that attribute, doesn't respond with the attribute, then as far as IPP is concerned, that implementation does not support that feature. If the Printer object's "xxx-supported" attribute is not populated with a particular value (even if that value is a legal value for that attribute), then that Printer object does not support that particular value.

A conforming implementation MUST support all REQUIRED attributes. However, even for REQUIRED attributes, conformance to IPP does not mandate that all implementations support all possible values representing all possible job processing behaviors and features. For example, if a given instance of a Printer supports only certain document formats, then that Printer responds with the "document- format-supported" attribute populated with a set of values, possibly only one, taken from the entire set of possible values defined for that attribute. This limited set of values represents the Printer's set of supported document formats. Supporting an attribute and some set of values for that attribute enables IPP end users to be aware of and make use of those features associated with that attribute and those values. If an implementation chooses to not support an attribute or some specific value, then IPP end users would have no ability to make use of that feature within the context of IPP itself. However, due to existing practice and legacy systems which are not IPP aware, there might be some other mechanism outside the scope of IPP to control or request the "unsupported" feature (such as embedded instructions within the document data itself).

For example, consider the "finishings-supported" attribute.

      1) If a Printer object is not physically capable of stapling, the
         "finishings-supported" attribute MUST NOT be populated with the
         value of 'staple'.
      2) A Printer object is physically capable of stapling, however an
         implementation chooses not to support stapling in the IPP
         "finishings" attribute.  In this case, 'staple' MUST NOT be a
         value in the "finishings-supported" Printer object attribute.
         Without support for the value 'staple', an IPP end user would
         have no means within the protocol itself to request that a Job
         be stapled.  However, an existing document data formatter might
         be able to request that the document be stapled directly with
         an embedded instruction within the document data.  In this
         case, the IPP implementation does not "support" stapling,
         however the end user is still able to have some control over
         the stapling of the completed job.
      3) A Printer object is physically capable of stapling, and an
         implementation chooses to support stapling in the IPP
         "finishings" attribute. In this case, 'staple' MUST be a value
         in the "finishings-supported" Printer object attribute. Doing
         so, would enable end users to be aware of and make use of the
         stapling feature using IPP attributes.

Even though support for Job Template attributes by a Printer object is OPTIONAL, it is RECOMMENDED that if the device behind a Printer object is capable of realizing any feature or function that corresponds to an IPP attribute and some associated value, then that implementation SHOULD support that IPP attribute and value.

The set of values in any of the supported value attributes is set (populated) by some administrative process or automatic sensing mechanism that is outside the scope of this IPP/1.1 document. For administrative policy and control reasons, an administrator may choose to make only a subset of possible values visible to the end user. In this case, the real output device behind the IPP Printer abstraction may be capable of a certain feature, however an administrator is specifying that access to that feature not be exposed to the end user through the IPP protocol. Also, since a Printer object may represent a logical print device (not just a physical device) the actual process for supporting a value is undefined and left up to the implementation. However, if a Printer object supports a value, some manual human action may be needed to realize the semantic action associated with the value, but no end user action is required.

For example, if one of the values in the "finishings-supported" attribute is 'staple', the actual process might be an automatic staple action by a physical device controlled by some command sent to the device. Or, the actual process of stapling might be a manual action by an operator at an operator attended Printer object.

For another example of how supported attributes function, consider a system administrator who desires to control all print jobs so that no job sheets are printed in order to conserve paper. To force no job sheets, the system administrator sets the only supported value for the "job-sheets-supported" attribute to 'none'. In this case, if a client requests anything except 'none', the create request is rejected or the "job-sheets" value is ignored (depending on the value of "ipp-attribute-fidelity"). To force the use of job start/end sheets on all jobs, the administrator does not include the value 'none' in the "job-sheets- supported" attribute. In this case, if a client requests 'none', the create request is rejected or the "job- sheets" value is ignored (again depending on the value of "ipp- attribute-fidelity").

12.2.4 print-stream page

A "print-stream page" is a page according to the definition of pages in the language used to express the document data.

12.2.5 impression

An "impression" is the image (possibly many print-stream pages in different configurations) imposed onto a single media page.

13. APPENDIX B: Status Codes and Suggested Status Code Messages

This section defines status code enum keywords and values that are used to provide semantic information on the results of an operation request. Each operation response MUST include a status code. The response MAY also contain a status message that provides a short textual description of the status. The status code is intended for use by automata, and the status message is intended for the human end user. Since the status message is an OPTIONAL component of the operation response, an IPP application (i.e., a browser, GUI, print driver or gateway) is NOT REQUIRED to examine or display the status message, since it MAY not be returned to the application.

The prefix of the status keyword defines the class of response as follows:

      "informational" - Request received, continuing process
      "successful" - The action was successfully received, understood,
         and accepted
      "redirection" - Further action must be taken in order to complete
         the request
      "client-error" - The request contains bad syntax or cannot be
         fulfilled
      "server-error" - The IPP object  failed to fulfill an apparently
         valid request

As with type2 enums, IPP status codes are extensible. IPP clients are NOT REQUIRED to understand the meaning of all registered status codes, though such understanding is obviously desirable. However, IPP clients MUST understand the class of any status code, as indicated by the prefix, and treat any unrecognized response as being equivalent to the first status code of that class, with the exception that an unrecognized response MUST NOT be cached. For example, if an unrecognized status code of "client-error-xxx-yyy" is received by the client, it can safely assume that there was something wrong with its request and treat the response as if it had received a "client- error-bad-request" status code. In such cases, IPP applications SHOULD present the OPTIONAL message (if present) to the end user since the message is likely to contain human readable information which will help to explain the unusual status. The name of the enum is the suggested status message for US English.

The status code values range from 0x0000 to 0x7FFF. The value ranges for each status code class are as follows:

"successful" - 0x0000 to 0x00FF
"informational" - 0x0100 to 0x01FF
"redirection" - 0x0200 to 0x02FF
"client-error" - 0x0400 to 0x04FF
"server-error" - 0x0500 to 0x05FF

The top half (128 values) of each range (0x0n40 to 0x0nFF, for n = 0 to 5) is reserved for vendor use within each status code class. Values 0x0600 to 0x7FFF are reserved for future assignment by IETF standards track documents and MUST NOT be used.

13.1 Status Codes

Each status code is described below. Section 13.1.5.9 contains a table that indicates which status codes apply to which operations. The Implementer's Guide [IPP-IIG] describe the suggested steps for processing IPP attributes for all operations, including returning status codes.

13.1.1 Informational

This class of status code indicates a provisional response and is to be used for informational purposes only.

There are no status codes defined in IPP/1.1 for this class of status code.

13.1.2 Successful Status Codes

This class of status code indicates that the client's request was successfully received, understood, and accepted.

13.1.2.1 successful-ok (0x0000)

The request has succeeded and no request attributes were substituted or ignored. In the case of a response to a create request, the 'successful-ok' status code indicates that the request was successfully received and validated, and that the Job object has been created; it does not indicate that the job has been processed. The transition of the Job object into the 'completed' state is the only indicator that the job has been printed.

13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001)

   The request has succeeded, but some supplied (1) attributes were
   ignored or (2) unsupported values were substituted with supported
   values or were ignored in order to perform the operation without
   rejecting it.  Unsupported attributes, attribute syntaxes, or values
   MUST be returned in the Unsupported Attributes group of the response
   for all operations.  There is an exception to this rule for the query
   operations:  Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes
   for the "requested-attributes" operation attribute only.  When the
   supplied values of the "requested-attributes" operation attribute are
   requesting attributes that are not supported, the IPP object MAY, but
   is NOT REQUIRED to, return the "requested-attributes" attribute in
   the Unsupported Attribute response group (with the unsupported values
   only).  See sections 3.1.7 and 3.2.1.2.

13.1.2.3 successful-ok-conflicting-attributes (0x0002)

The request has succeeded, but some supplied attribute values conflicted with the values of other supplied attributes. These conflicting values were either (1) substituted with (supported) values or (2) the attributes were removed in order to process the job without rejecting it. Attributes or values which conflict with other attributes and have been substituted or ignored MUST be returned in the Unsupported Attributes group of the response for all operations as supplied by the client. See sections 3.1.7 and 3.2.1.2.

13.1.3 Redirection Status Codes

This class of status code indicates that further action needs to be taken to fulfill the request.

There are no status codes defined in IPP/1.1 for this class of status code.

13.1.4 Client Error Status Codes

This class of status code is intended for cases in which the client seems to have erred. The IPP object SHOULD return a message containing an explanation of the error situation and whether it is a temporary or permanent condition.

13.1.4.1 client-error-bad-request (0x0400)

The request could not be understood by the IPP object due to malformed syntax (such as the value of a fixed length attribute whose length does not match the prescribed length for that attribute - see the Implementer's Guide [IPP-IIG] ). The IPP application SHOULD NOT repeat the request without modifications.

13.1.4.2 client-error-forbidden (0x0401)

The IPP object understood the request, but is refusing to fulfill it. Additional authentication information or authorization credentials will not help and the request SHOULD NOT be repeated. This status code is commonly used when the IPP object does not wish to reveal exactly why the request has been refused or when no other response is applicable.

13.1.4.3 client-error-not-authenticated (0x0402)

The request requires user authentication. The IPP client may repeat the request with suitable authentication information. If the request already included authentication information, then this status code indicates that authorization has been refused for those credentials. If this response contains the same challenge as the prior response, and the user agent has already attempted authentication at least once, then the response message may contain relevant diagnostic information. This status codes reveals more information than "client-error-forbidden".

13.1.4.4 client-error-not-authorized (0x0403)

The requester is not authorized to perform the request. Additional authentication information or authorization credentials will not help and the request SHOULD NOT be repeated. This status code is used when the IPP object wishes to reveal that the authentication information is understandable, however, the requester is explicitly not authorized to perform the request. This status codes reveals more information than "client-error-forbidden" and "client-error- not-authenticated".

13.1.4.5 client-error-not-possible (0x0404)

This status code is used when the request is for something that can not happen. For example, there might be a request to cancel a job that has already been canceled or aborted by the system. The IPP client SHOULD NOT repeat the request.

13.1.4.6 client-error-timeout (0x0405)

   The client did not produce a request within the time that the IPP
   object was prepared to wait.  For example, a client issued a Create-
   Job operation and then, after a long period of time, issued a Send-
   Document operation and this error status code was returned in
   response to the Send-Document request  (see section 3.3.1).  The IPP
   object might have been forced to clean up resources that had been
   held for the waiting additional Documents.  The IPP object was forced
   to close the Job since the client took too long.  The client SHOULD
   NOT repeat the request without modifications.

13.1.4.7 client-error-not-found (0x0406)

The IPP object has not found anything matching the request URI. No indication is given of whether the condition is temporary or permanent. For example, a client with an old reference to a Job (a URI) tries to cancel the Job, however in the mean time the Job might have been completed and all record of it at the Printer has been deleted. This status code, 'client-error-not-found' is returned indicating that the referenced Job can not be found. This error status code is also used when a client supplies a URI as a reference to the document data in either a Print-URI or Send-URI operation, but the document can not be found.

In practice, an IPP application should avoid a not found situation by first querying and presenting a list of valid Printer URIs and Job URIs to the end-user.

13.1.4.8 client-error-gone (0x0407)

The requested object is no longer available and no forwarding address is known. This condition should be considered permanent. Clients with link editing capabilities should delete references to the request URI after user approval. If the IPP object does not know or has no facility to determine, whether or not the condition is permanent, the status code "client-error-not-found" should be used instead.

This response is primarily intended to assist the task of maintenance by notifying the recipient that the resource is intentionally unavailable and that the IPP object administrator desires that remote links to that resource be removed. It is not necessary to mark all permanently unavailable resources as "gone" or to keep the mark for any length of time -- that is left to the discretion of the IPP object administrator and/or Printer implementation.

13.1.4.9 client-error-request-entity-too-large (0x0408)

The IPP object is refusing to process a request because the request entity is larger than the IPP object is willing or able to process. An IPP Printer returns this status code when it limits the size of print jobs and it receives a print job that exceeds that limit or when the attributes are so many that their encoding causes the request entity to exceed IPP object capacity.

13.1.4.10 client-error-request-value-too-long (0x0409)

The IPP object is refusing to service the request because one or more of the client-supplied attributes has a variable length value that is longer than the maximum length specified for that attribute. The IPP object might not have sufficient resources (memory, buffers, etc.) to process (even temporarily), interpret, and/or ignore a value larger than the maximum length. Another use of this error code is when the IPP object supports the processing of a large value that is less than the maximum length, but during the processing of the request as a whole, the object may pass the value onto some other system component which is not able to accept the large value. For more details, see the Implementer's Guide [IPP-IIG] .

   Note:  For attribute values that are URIs, this rare condition is
   only likely to occur when a client has improperly submitted a request
   with long query information (e.g. an IPP application allows an end-
   user to enter an invalid URI), when the client has descended into a
   URI "black hole" of redirection (e.g., a redirected URI prefix that
   points to a suffix of itself), or when the IPP object is under attack
   by a client attempting to exploit security holes present in some IPP
   objects using fixed-length buffers for reading or manipulating the
   Request-URI.

13.1.4.11 client-error-document-format-not-supported (0x040A)

The IPP object is refusing to service the request because the document data is in a format, as specified in the "document-format" operation attribute, that is not supported by the Printer object. This error is returned independent of the client-supplied "ipp- attribute-fidelity". The Printer object MUST return this status code, even if there are other Job Template attributes that are not supported as well, since this error is a bigger problem than with Job Template attributes. See sections 3.1.6.1, 3.1.7, and 3.2.1.1.

13.1.4.12 client-error-attributes-or-values-not-supported (0x040B)

In a create request, if the Printer object does not support one or more attributes, attribute syntaxes, or attribute values supplied in the request and the client supplied the "ipp-attribute-fidelity" operation attribute with the 'true' value, the Printer object MUST return this status code. The Printer object MUST also return in the Unsupported Attributes Group all the attributes and/or values supplied by the client that are not supported. See section 3.1.7. For example, if the request indicates 'iso-a4' media, but that media type is not supported by the Printer object. Or, if the client supplies a Job Template attribute and the attribute itself is not even supported by the Printer. If the "ipp-attribute-fidelity" attribute is 'false', the Printer MUST ignore or substitute values for unsupported Job Template attributes and values rather than reject the request and return this status code.

For any operation where a client requests attributes (such as a Get- Jobs, Get-Printer-Attributes, or Get-Job-Attributes operation), if the IPP object does not support one or more of the requested attributes, the IPP object simply ignores the unsupported requested attributes and processes the request as if they had not been supplied, rather than returning this status code. In this case, the IPP object MUST return the 'successful-ok-ignored-or-substituted- attributes' status code and MAY return the unsupported attributes as values of the "requested-attributes" in the Unsupported Attributes Group (see section 13.1.2.2).

13.1.4.13 client-error-uri-scheme-not-supported (0x040C)

The scheme of the client-supplied URI in a Print-URI or a Send-URI operation is not supported. See sections 3.1.6.1 and 3.1.7.

13.1.4.14 client-error-charset-not-supported (0x040D)

   For any operation, if the IPP Printer does not support the charset
   supplied by the client in the "attributes-charset" operation
   attribute, the Printer MUST reject the operation and return this
   status and any 'text' or 'name' attributes using the 'utf-8' charset
   (see Section 3.1.4.1).  See sections 3.1.6.1 and  3.1.7.

13.1.4.15 client-error-conflicting-attributes (0x040E)

The request is rejected because some attribute values conflicted with the values of other attributes which this document does not permit to be substituted or ignored. The Printer object MUST also return in the Unsupported Attributes Group the conflicting attributes supplied by the client. See sections 3.1.7 and 3.2.1.2.

13.1.4.16 client-error-compression-not-supported (0x040F)

The IPP object is refusing to service the request because the document data, as specified in the "compression" operation attribute, is compressed in a way that is not supported by the Printer object. This error is returned independent of the client-supplied "ipp- attribute-fidelity". The Printer object MUST return this status code, even if there are other Job Template attributes that are not supported as well, since this error is a bigger problem than with Job Template attributes. See sections 3.1.6.1, 3.1.7, and 3.2.1.1.

13.1.4.17 client-error-compression-error (0x0410)

The IPP object is refusing to service the request because the document data cannot be decompressed when using the algorithm specified by the "compression" operation attribute. This error is returned independent of the client-supplied "ipp-attribute-fidelity". The Printer object MUST return this status code, even if there are Job Template attributes that are not supported as well, since this error is a bigger problem than with Job Template attributes. See sections 3.1.7 and 3.2.1.1.

13.1.4.18 client-error-document-format-error (0x0411)

The IPP object is refusing to service the request because Printer encountered an error in the document data while interpreting it. This error is returned independent of the client-supplied "ipp- attribute-fidelity". The Printer object MUST return this status code, even if there are Job Template attributes that are not supported as well, since this error is a bigger problem than with Job Template attributes. See sections 3.1.7 and 3.2.1.1.

13.1.4.19 client-error-document-access-error (0x0412)

The IPP object is refusing to service the Print-URI or Send-URI request because Printer encountered an access error while attempting to validate the accessibility or access the document data specified in the "document-uri" operation attribute. The Printer MAY also return a specific document access error code using the "document- access-error" operation attribute (see section 3.1.6.4). This error is returned independent of the client-supplied "ipp-attribute- fidelity". The Printer object MUST return this status code, even if there are Job Template attributes that are not supported as well, since this error is a bigger problem than with Job Template attributes. See sections 3.1.6.1 and 3.1.7.

13.1.5 Server Error Status Codes

This class of status codes indicates cases in which the IPP object is aware that it has erred or is incapable of performing the request. The IPP object SHOULD include a message containing an explanation of the error situation, and whether it is a temporary or permanent condition.

13.1.5.1 server-error-internal-error (0x0500)

The IPP object encountered an unexpected condition that prevented it from fulfilling the request. This error status code differs from "server-error-temporary-error" in that it implies a more permanent type of internal error. It also differs from "server-error-device- error" in that it implies an unexpected condition (unlike a paper-jam or out-of-toner problem which is undesirable but expected). This error status code indicates that probably some knowledgeable human intervention is required.

13.1.5.2 server-error-operation-not-supported (0x0501)

The IPP object does not support the functionality required to fulfill the request. This is the appropriate response when the IPP object does not recognize an operation or is not capable of supporting it. See sections 3.1.6.1 and 3.1.7.

13.1.5.3 server-error-service-unavailable (0x0502)

The IPP object is currently unable to handle the request due to a temporary overloading or maintenance of the IPP object. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay may be indicated in the message. If no delay is given, the IPP application should handle the response as it would for a "server-error- temporary-error" response. If the condition is more permanent, the error status codes "client-error-gone" or "client-error-not-found" could be used.

13.1.5.4 server-error-version-not-supported (0x0503)

The IPP object does not support, or refuses to support, the IPP protocol version that was supplied as the value of the "version- number" operation parameter in the request. The IPP object is indicating that it is unable or unwilling to complete the request using the same major and minor version number as supplied in the request other than with this error message. The error response SHOULD contain a "status-message" attribute (see section 3.1.6.2) describing why that version is not supported and what other versions are supported by that IPP object. See sections 3.1.6.1, 3.1.7, and 3.1.8.

The error response MUST identify in the "version-number" operation parameter the closest version number that the IPP object does support. For example, if a client supplies version '1.0' and an IPP/1.1 object supports version '1.0', then it responds with version '1.0' in all responses to such a request. If the IPP/1.1 object does not support version '1.0', then it should accept the request and respond with version '1.1' or may reject the request and respond with this error code and version
'1.1'. If a client supplies a version '1.2', the IPP/1.1 object should accept the request and return version '1.1' or may reject the request and respond with this error code and version '1.1'. See sections 3.1.8 and 4.4.14.

13.1.5.5 server-error-device-error (0x0504)

A printer error, such as a paper jam, occurs while the IPP object processes a Print or Send operation. The response contains the true Job Status (the values of the "job-state" and "job-state-reasons" attributes). Additional information can be returned in the OPTIONAL "job-state-message" attribute value or in the OPTIONAL status message that describes the error in more detail. This error status code is only returned in situations where the Printer is unable to accept the create request because of such a device error. For example, if the Printer is unable to spool, and can only accept one job at a time, the reason it might reject a create request is that the printer currently has a paper jam. In many cases however, where the Printer object can accept the request even though the Printer has some error condition, the 'successful-ok' status code will be returned. In such a case, the client would look at the returned Job Object Attributes or later query the Printer to determine its state and state reasons.

13.1.5.6 server-error-temporary-error (0x0505)

A temporary error such as a buffer full write error, a memory overflow (i.e. the document data exceeds the memory of the Printer), or a disk full condition, occurs while the IPP Printer processes an operation. The client MAY try the unmodified request again at some later point in time with an expectation that the temporary internal error condition may have been cleared. Alternatively, as an implementation option, a Printer object MAY delay the response until the temporary condition is cleared so that no error is returned.

13.1.5.7 server-error-not-accepting-jobs (0x0506)

A temporary error indicating that the Printer is not currently accepting jobs, because the administrator has set the value of the Printer's "printer-is-accepting-jobs" attribute to 'false' (by means outside the scope of this IPP/1.1 document).

13.1.5.8 server-error-busy (0x0507)

A temporary error indicating that the Printer is too busy processing jobs and/or other requests. The client SHOULD try the unmodified request again at some later point in time with an expectation that the temporary busy condition will have been cleared.

13.1.5.9 server-error-job-canceled (0x0508)

An error indicating that the job has been canceled by an operator or the system while the client was transmitting the data to the IPP Printer. If a job-id and job-uri had been created, then they are returned in the Print-Job, Send-Document, or Send-URI response as usual; otherwise, no job-id and job-uri are returned in the response.

13.1.5.10 server-error-multiple-document-jobs-not-supported (0x0509)

The IPP object does not support multiple documents per job and a client attempted to supply document data with a second Send-Document or Send-URI operation.

13.2 Status Codes for IPP Operations

   PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document
   SU = Send-URI, V = Validate-Job, GA = Get-Job-Attributes and
   Get-Printer-Attributes, GJ = Get-Jobs, C = Cancel-Job
                                                  IPP Operations
   IPP Status Keyword                       PJ PU CJ SD SU V GA GJ C
   ------------------                       -- -- -- -- -- - -- -- -
   successful-ok                            x  x  x  x  x  x x  x  x
   successful-ok-ignored-or-substituted-    x  x  x  x  x  x x  x  x
        attributes
   successful-ok-conflicting-attributes     x  x  x  x  x  x x  x  x
   client-error-bad-request                 x  x  x  x  x  x x  x  x
   client-error-forbidden                   x  x  x  x  x  x x  x  x
   client-error-not-authenticated           x  x  x  x  x  x x  x  x
   client-error-not-authorized              x  x  x  x  x  x x  x  x
   client-error-not-possible                x  x  x  x  x  x x  x  x
   client-error-timeout                              x  x
   client-error-not-found                   x  x  x  x  x  x x  x  x
   client-error-gone                        x  x  x  x  x  x x  x  x
   client-error-request-entity-too-large    x  x  x  x  x  x x  x  x
   client-error-request-value-too-long      x  x  x  x  x  x x  x  x
   client-error-document-format-not-        x  x     x  x  x x
        supported
   client-error-attributes-or-values-not-   x  x  x  x  x  x x  x  x
        supported
   client-error-uri-scheme-not-supported       x        x
   client-error-charset-not-supported       x  x  x  x  x  x x  x  x
   client-error-conflicting-attributes      x  x  x  x  x  x x  x  x
   client-error-compression-not-supported   x  x     x  x  x
   client-error-compression-error           x  x     x  x
   client-error-document-format-error       x  x     x  x
   client-error-document-access-error          x        x
   server-error-internal-error              x  x  x  x  x  x x  x  x
   server-error-operation-not-supported        x  x  x  x
   server-error-service-unavailable         x  x  x  x  x  x x  x  x
   server-error-version-not-supported       x  x  x  x  x  x x  x  x
   server-error-device-error                x  x  x  x  x
   server-error-temporary-error             x  x  x  x  x
   server-error-not-accepting-jobs          x  x  x        x
   server-error-busy                        x  x  x  x  x  x x  x  x
   server-error-job-canceled                x        x  x
   server-error-multiple-document-jobs-              x  x
          not-supported
   
   HJ = Hold-Job, RJ = Release-Job, RS = Restart-Job
   PP = Pause-Printer, RP = Resume-Printer, PJ = Purge-Jobs
                                            IPP Operations (cont.)
   IPP Status Keyword                       HJ RJ RS PP RP PJ
   ------------------                       -- -- -- -- -- --
   successful-ok                            x  x  x  x  x  x
   successful-ok-ignored-or-substituted-    x  x  x  x  x  x
        attributes
   successful-ok-conflicting-attributes     x  x  x  x  x  x
   client-error-bad-request                 x  x  x  x  x  x
   client-error-forbidden                   x  x  x  x  x  x
   client-error-not-authenticated           x  x  x  x  x  x
   client-error-not-authorized              x  x  x  x  x  x
   client-error-not-possible                x  x  x  x  x  x
   client-error-timeout
   client-error-not-found                   x  x  x  x  x  x
   client-error-gone                        x  x  x  x  x  x
   client-error-request-entity-too-large    x  x  x  x  x  x
   client-error-request-value-too-long      x  x  x  x  x  x
   client-error-document-format-not-
        supported
   client-error-attributes-or-values-not-   x  x  x  x  x  x
        supported
   client-error-uri-scheme-not-supported
   client-error-charset-not-supported       x  x  x  x  x  x
   client-error-conflicting-attributes      x  x  x  x  x  x
   client-error-compression-not-supported
   client-error-compression-error
   client-error-document-format-error
   client-error-document-access-error
   server-error-internal-error              x  x  x  x  x  x
   server-error-operation-not-supported     x  x  x  x  x  x
   server-error-service-unavailable         x  x  x  x  x  x
   server-error-version-not-supported       x  x  x  x  x  x
   server-error-device-error
   server-error-temporary-error             x  x  x  x  x  x
   server-error-not-accepting-jobs
   server-error-busy                        x  x  x  x  x  x
   server-error-job-canceled
   server-error-multiple-document-jobs-
          not-supported

14. APPENDIX C: "media" keyword values

Standard keyword values are taken from several sources.

Standard values are defined (taken from DPA[ISO10175] and the Printer MIB[RFC1759]):

    'default': The default medium for the output device
    'iso-a4-white': Specifies the ISO A4 white medium: 210 mm x 297 mm
    'iso-a4-colored': Specifies the ISO A4 colored medium: 210 mm x 297
       mm
    'iso-a4-transparent' Specifies the ISO A4 transparent medium: 210 mm
       x 297 mm
    'iso-a3-white': Specifies the ISO A3 white medium: 297 mm x 420 mm
    'iso-a3-colored': Specifies the ISO A3 colored medium: 297 mm x 420
       mm
    'iso-a5-white': Specifies the ISO A5 white medium: 148 mm x 210 mm
    'iso-a5-colored': Specifies the ISO A5 colored medium: 148 mm x 210
       mm
    'iso-b4-white': Specifies the ISO B4 white medium: 250 mm x 353 mm
    'iso-b4-colored': Specifies the ISO B4 colored medium: 250 mm x 353
       mm
    'iso-b5-white': Specifies the ISO B5 white medium: 176 mm x 250 mm
    'iso-b5-colored': Specifies the ISO B5 colored medium: 176 mm x 250
       mm
    'jis-b4-white': Specifies the JIS B4 white medium: 257 mm x 364 mm
    'jis-b4-colored': Specifies the JIS B4 colored medium: 257 mm x 364
       mm
    'jis-b5-white': Specifies the JIS B5 white medium: 182 mm x 257 mm
    'jis-b5-colored': Specifies the JIS B5 colored medium: 182 mm x 257
       mm

The following standard values are defined for North American media:

    'na-letter-white': Specifies the North American letter white medium
    'na-letter-colored': Specifies the North American letter colored
       medium
    'na-letter-transparent': Specifies the North American letter
       transparent medium
    'na-legal-white': Specifies the North American legal white medium
    'na-legal-colored': Specifies the North American legal colored
       medium

The following standard values are defined for envelopes:

    'iso-b4-envelope': Specifies the ISO B4 envelope medium
    'iso-b5-envelope': Specifies the ISO B5 envelope medium
    'iso-c3-envelope': Specifies the ISO C3 envelope medium
    'iso-c4-envelope': Specifies the ISO C4 envelope medium
    'iso-c5-envelope': Specifies the ISO C5 envelope medium
    'iso-c6-envelope': Specifies the ISO C6 envelope medium
    'iso-designated-long-envelope': Specifies the ISO Designated Long
       envelope medium
    'na-10x13-envelope': Specifies the North American 10x13 envelope
       medium
    'na-9x12-envelope': Specifies the North American 9x12 envelope
       medium
    'monarch-envelope': Specifies the Monarch envelope
    'na-number-10-envelope': Specifies the North American number 10
       business envelope medium
    'na-7x9-envelope': Specifies the North American 7x9 inch envelope
    'na-9x11-envelope': Specifies the North American 9x11 inch
       envelope
    'na-10x14-envelope': Specifies the North American 10x14 inch
       envelope
    'na-number-9-envelope': Specifies the North American number 9
       business envelope
    'na-6x9-envelope': Specifies the North American 6x9 inch envelope
    'na-10x15-envelope': Specifies the North American 10x15 inch
       envelope

The following standard values are defined for the less commonly used media:

 'executive-white': Specifies the white executive medium
 'folio-white': Specifies the folio white medium
 'invoice-white': Specifies the white invoice medium
 'ledger-white': Specifies the white ledger medium
 'quarto-white': Specified the white quarto medium
 'iso-a0-white': Specifies the ISO A0 white medium: 841 mm x 1189 mm
 'iso-a0-transparent': Specifies the ISO A0 transparent medium: 841 mm
    x 1189 mm
 'iso-a0-translucent': Specifies the ISO A0 translucent medium: 841 mm
    x 1189 mm
 'iso-a1-white': Specifies the ISO A1 white medium: 594 mm x 841 mm
 'iso-a1-transparent': Specifies the ISO A1 transparent medium: 594 mm
    x 841 mm
 'iso-a1-translucent': Specifies the ISO A1 translucent medium: 594 mm
    x 841 mm
 'iso-a2-white': Specifies the ISO A2 white medium: 420 mm x 594 mm
 
 'iso-a2-transparent': Specifies the ISO A2 transparent medium: 420 mm
    x 594 mm
 'iso-a2-translucent': Specifies the ISO A2 translucent medium: 420 mm
    x 594 mm
 'iso-a3-transparent': Specifies the ISO A3 transparent medium: 297 mm
    x 420 mm
 'iso-a3-translucent': Specifies the ISO A3 translucent medium: 297 mm
    x 420 mm
 'iso-a4-translucent': Specifies the ISO A4 translucent medium: 210 mm
    x 297 mm
 'iso-a5-transparent': Specifies the ISO A5 transparent medium: 148 mm
    x 210 mm
 'iso-a5-translucent': Specifies the ISO A5 translucent medium: 148 mm
    x 210 mm
 'iso-a6-white': Specifies the ISO A6 white medium: 105 mm x 148 mm
 'iso-a7-white': Specifies the ISO A7 white medium: 74 mm x 105 mm
 'iso-a8-white': Specifies the ISO A8 white medium: 52 mm x 74 mm
 'iso-a9-white': Specifies the ISO A9 white medium: 37 mm x 52 mm
 'iso-a10-white': Specifies the ISO A10 white medium: 26 mm x 37 mm
 'iso-b0-white': Specifies the ISO B0 white medium: 1000 mm x 1414 mm
 'iso-b1-white': Specifies the ISO B1 white medium: 707 mm x 1000 mm
 'iso-b2-white': Specifies the ISO B2 white medium: 500 mm x 707 mm
 'iso-b3-white': Specifies the ISO B3 white medium: 353 mm x 500 mm
 'iso-b6-white': Specifies the ISO B6 white medium: 125 mm x 176 mm
 'iso-b7-white': Specifies the ISO B7 white medium: 88 mm x 125 mm
 'iso-b8-white': Specifies the ISO B8 white medium: 62 mm x 88 mm
 'iso-b9-white': Specifies the ISO B9 white medium: 44 mm x 62 mm
 'iso-b10-white': Specifies the ISO B10 white medium: 31 mm x 44 mm
 'jis-b0-white': Specifies the JIS B0 white medium: 1030 mm x 1456 mm
 'jis-b0-transparent': Specifies the JIS B0 transparent medium: 1030
    mm x 1456 mm
 'jis-b0-translucent': Specifies the JIS B0 translucent medium: 1030
    mm x 1456 mm
 'jis-b1-white': Specifies the JIS B1 white medium: 728 mm x 1030 mm
 'jis-b1-transparent': Specifies the JIS B1 transparent medium: 728 mm
    x 1030 mm
 'jis-b1-translucent': Specifies the JIS B1 translucent medium: 728 mm
    x 1030 mm
 'jis-b2-white': Specifies the JIS B2 white medium: 515 mm x 728 mm
 'jis-b2-transparent': Specifies the JIS B2 transparent medium: 515 mm
    x 728 mm
 'jis-b2-translucent': Specifies the JIS B2 translucent medium: 515 mm
    x 728 mm
 'jis-b3-white': Specifies the JIS B3 white medium: 364 mm x 515 mm
 'jis-b3-transparent': Specifies the JIS B3 transparent medium: 364 mm
    x 515 mm
 'jis-b3-translucent': Specifies the JIS B3 translucent medium: 364 mm
    x 515 mm
 'jis-b4-transparent': Specifies the JIS B4 transparent medium: 257 mm
    x 364 mm
 'jis-b4-translucent': Specifies the JIS B4 translucent medium: 257 mm
    x 364 mm
 'jis-b5-transparent': Specifies the JIS B5 transparent medium: 182 mm
    x 257 mm
 'jis-b5-translucent': Specifies the JIS B5 translucent medium: 182 mm
    x 257 mm
 'jis-b6-white': Specifies the JIS B6 white medium: 128 mm x 182 mm
 'jis-b7-white': Specifies the JIS B7 white medium: 91 mm x 128 mm
 'jis-b8-white': Specifies the JIS B8 white medium: 64 mm x 91 mm
 'jis-b9-white': Specifies the JIS B9 white medium: 45 mm x 64 mm
 'jis-b10-white': Specifies the JIS B10 white medium: 32 mm x 45 mm

The following standard values are defined for American Standard (i.e. ANSI) engineering media:

    'a-white': Specifies the engineering ANSI A size white medium: 8.5
       inches x 11 inches
    'a-transparent': Specifies the engineering ANSI A size transparent
       medium: 8.5 inches x 11 inches
    'a-translucent': Specifies the engineering ANSI A size translucent
       medium: 8.5 inches x 11 inches
    'b-white': Specifies the engineering ANSI B size white medium: 11
       inches x 17 inches
    'b-transparent': Specifies the engineering ANSI B size transparent
       medium: 11 inches x 17 inches)
    'b-translucent': Specifies the engineering ANSI B size translucent
       medium: 11 inches x 17 inches
    'c-white': Specifies the engineering ANSI C size white medium: 17
       inches x 22 inches
    'c-transparent': Specifies the engineering ANSI C size transparent
       medium: 17 inches x 22 inches
    'c-translucent': Specifies the engineering ANSI C size translucent
       medium: 17 inches x 22 inches
    'd-white': Specifies the engineering ANSI D size white medium: 22
       inches x 34 inches
    'd-transparent': Specifies the engineering ANSI D size transparent
       medium: 22 inches x 34 inches
    'd-translucent': Specifies the engineering ANSI D size translucent
       medium: 22 inches x 34 inches
    'e-white': Specifies the engineering ANSI E size white medium: 34
       inches x 44 inches
    'e-transparent': Specifies the engineering ANSI E size transparent
       medium: 34 inches x 44 inches
    'e-translucent': Specifies the engineering ANSI E size translucent
       medium: 34 inches x 44 inches

The following standard values are defined for American Standard (i.e. ANSI) engineering media for devices that provide the "synchro-cut" feature (see section 14.1):

 'axsynchro-white': Specifies the roll paper having the width of the
    longer edge (11 inches) of the engineering ANSI A size white medium
    and cuts synchronizing with data.
 'axsynchro-transparent': Specifies the roll paper having the width of
    the longer edge (11 inches) of the engineering ANSI A size
    transparent medium and cuts synchronizing with data.
 'axsynchro-translucent': Specifies the roll paper having the width of
    the longer edge (11 inches) of the engineering ANSI A size
    translucent medium and cuts synchronizing with data.
 'bxsynchro-white': Specifies the roll paper having the width of the
    longer edge (17 inches) of the engineering ANSI B size white medium
    and cuts synchronizing with data.
 'bxsynchro-transparent': Specifies the roll paper having the width of
    the longer edge (17 inches) of the engineering ANSI B size
    transparent medium and cuts synchronizing with data.
 'bxsynchro-translucent': Specifies the roll paper having the width of
    the longer edge (17 inches) of the engineering ANSI B size
    translucent medium and cuts synchronizing with data.
 'cxsynchro-white': Specifies the roll paper having the width of the
    longer edge (22 inches) of the engineering ANSI C size white medium
    and cuts synchronizing with data.
 'cxsynchro-transparent': Specifies the roll paper having the width of
    the longer edge (22 inches) of the engineering ANSI C size
    transparent medium and cuts synchronizing with data.
 'cxsynchro-translucent': Specifies the roll paper having the width of
    the longer edge (22 inches) of the engineering ANSI C size
    translucent medium and cuts synchronizing with data.
 'dxsynchro-white': Specifies the roll paper having the width of the
    longer edge (34 inches) of the engineering ANSI D size white medium
    and cuts synchronizing with data.
 'dxsynchro-transparent': Specifies the roll paper having the width of
    the longer edge (34 inches) of the engineering ANSI D size
    transparent medium and cuts synchronizing with data.
 'dxsynchro-translucent': Specifies the roll paper having the width of
    the longer edge (34 inches) of the engineering ANSI D size
    translucent medium and cuts synchronizing with data.
 'exsynchro-white': Specifies the roll paper having the width of the
    longer edge (44 inches) of the engineering ANSI E size white medium
    and cuts synchronizing with data.
 'exsynchro-transparent': Specifies the roll paper having the width of
    the longer edge (44 inches) of the engineering ANSI E size
    transparent medium and cuts synchronizing with data.

'exsynchro-translucent': Specifies the roll paper having the width of

the longer edge (44 inches) of the engineering ANSI E size translucent medium and cuts synchronizing with data.

The following standard values are defined for American Architectural engineering media:

 'arch-a-white': Specifies the Architectural A size white medium: 9
    inches x 12 inches
 'arch-a-transparent': Specifies the Architectural A size transparent
    medium: 9 inches x 12 inches
 'arch-a-translucent': Specifies the Architectural A size translucent
    medium: 9 inches x 12 inches
 'arch-b-white': Specifies the Architectural B size white medium: 12
    inches x 18 inches
 'arch-b-transparent': Specifies the Architectural B size transparent
    medium: 12 inches x 18 inches
 'arch-b-translucent': Specifies the Architectural B size translucent
    medium: 12 inches x 18 inches
 'arch-c-white': Specifies the Architectural C size white medium: 18
    inches x 24 inches
 'arch-c-transparent': Specifies the Architectural C size transparent
    medium: 18 inches x 24 inches
 'arch-c-translucent': Specifies the Architectural C size translucent
    medium: 18 inches x 24 inches
 'arch-d-white': Specifies the Architectural D size white medium: 24
    inches x 36 inches
 'arch-d-transparent': Specifies the Architectural D size transparent
    medium: 24 inches x 36 inches
 'arch-d-translucent': Specifies the Architectural D size translucent
    medium: 24 inches x 36 inches
 'arch-e-white': Specifies the Architectural E size white medium: 36
    inches x 48 inches
 'arch-e-transparent': Specifies the Architectural E size transparent
    medium: 36 inches x 48 inches
 'arch-e-translucent': Specifies the Architectural E size translucent
    medium: 36 inches x 48 inches

The following standard values are defined for American Architectural engineering media for devices that provide the "synchro-cut" feature (see section 14.1):

 'arch-axsynchro-white': Specifies the roll paper having the width of
    the longer edge (12 inches) of the Architectural A size white
    medium and cuts synchronizing with data.
 'arch-axsynchro-transparent': Specifies the roll paper having the
    width of the longer edge (12 inches) of the Architectural A size
    transparent medium and cuts synchronizing with data.
 'arch-axsynchro-translucent': Specifies the roll paper having the
    width of the longer edge (12 inches) of the Architectural A size
    translucent medium and cuts synchronizing with data.
 'arch-bxsynchro-white': Specifies the roll paper having the width of
    the longer edge (18 inches) of the Architectural B size white
    medium and cuts synchronizing with data.
 'arch-bxsynchro-transparent': Specifies the roll paper having the
    width of the longer edge (18 inches) of the Architectural B size
    transparent medium and cuts synchronizing with data.
 'arch-bxsynchro-translucent': Specifies the roll paper having the
    width of the longer edge (18 inches) of the Architectural B size
    translucent medium and cuts synchronizing with data.
 'arch-cxsynchro-white': Specifies the roll paper having the width of
    the longer edge (24 inches) of the Architectural C size white
    medium and cuts synchronizing with data.
 'arch-cxsynchro-transparent': Specifies the roll paper having the
    width of the longer edge (24 inches) of the Architectural C size
    transparent medium and cuts synchronizing with data.
 'arch-cxsynchro-translucent': Specifies the roll paper having the
    width of the longer edge (24 inches) of the Architectural C size
    translucent medium and cuts synchronizing with data.
 'arch-dxsynchro-white': Specifies the roll paper having the width of
    the longer edge (36 inches) of the Architectural D size white
    medium and cuts synchronizing with data.
 'arch-dxsynchro-transparent': Specifies the roll paper having the
    width of the longer edge (36 inches) of the Architectural D size
    transparent medium and cuts synchronizing with data.
 'arch-dxsynchro-translucent': Specifies the roll paper having the
    width of the longer edge (36 inches) of the Architectural D size
    translucent medium and cuts synchronizing with data.
 'arch-exsynchro-white': Specifies the roll paper having the width of
    the longer edge (48 inches) of the Architectural E size white
    medium and cuts synchronizing with data.
 'arch-exsynchro-transparent': Specifies the roll paper having the
    width of the longer edge (48 inches) of the Architectural E size
    transparent medium and cuts synchronizing with data.
 'arch-exsynchro-translucent': Specifies the roll paper having the
    width of the longer edge (48 inches) of the Architectural E size
    translucent medium and cuts synchronizing with data.

The following standard values are defined for Japanese and European Standard (i.e. ISO) engineering media, which are of a long fixed size [ASME-Y14.1M]:

'iso-a1x3-white': Specifies the ISO A1X3 white medium having the: width of the longer edge (841 mm) of the ISO A1 medium

 'iso-a1x3-transparent': Specifies the ISO A1X3 transparent medium
      having the width of the longer edge (841 mm) of the ISO A1
      medium
 'iso-a1x3-translucent': Specifies the ISO A1X3 translucent medium
      having the width of the longer edge (841 mm) of the ISO A1
      medium
 'iso-a1x4-white': Specifies the ISO A1X4 white medium having the
      width of the longer edge (841 mm) of the ISO A1 medium
 'iso-a1x4-transparent': Specifies the ISO A1X4 transparent medium
      having the width of the longer edge (841 mm) of the ISO A1
      medium
 'iso-a1x4- translucent': Specifies the ISO A1X4 translucent medium
      having the width of the longer edge (841 mm) of the ISO A1
      medium
 'iso-a2x3-white': Specifies the ISO A2X3 white medium having the
      width of the longer edge (594 mm) of the ISO A2 medium
 'iso-a2x3-transparent': Specifies the ISO A2X3 transparent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a2x3-translucent': Specifies the ISO A2X3 translucent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a2x4-white': Specifies the ISO A2X4 white medium having the
      width of the longer edge (594 mm) of the ISO A2 medium
 'iso-a2x4-transparent': Specifies the ISO A2X4 transparent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a2x4-translucent': Specifies the ISO A2X4 translucent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a2x5-white': Specifies the ISO A2X5 white medium having the
      width of the longer edge (594 mm) of the ISO A2 medium
 'iso-a2x5-transparent': Specifies the ISO A2X5 transparent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a2x5-translucent': Specifies the ISO A2X5 translucent medium
      having the width of the longer edge (594 mm) of the ISO A2
      medium
 'iso-a3x3-white': Specifies the ISO A3X3 white medium having the
      width of the longer edge (420 mm) of the ISO A3 medium
 'iso-a3x3-transparent': Specifies the ISO A3X3 transparent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x3-translucent': Specifies the ISO A3X3 translucent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x4-white': Specifies the ISO A3X4 white medium having the
      width of the longer edge (420 mm) of the ISO A3 medium
 'iso-a3x4-transparent': Specifies the ISO A3X4 transparent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x4-translucent': Specifies the ISO A3X4 translucent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x5-white': Specifies the ISO A3X5 white medium having the
      width of the longer edge (420 mm) of the ISO A3 medium
 'iso-a3x5-transparent': Specifies the ISO A3X5 transparent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x5-translucent': Specifies the ISO A3X5 translucent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x6-white': Specifies the ISO A3X6 white medium having the
      width of the longer edge (420 mm) of the ISO A3 medium
 'iso-a3x6-transparent': Specifies the ISO A3X6 transparent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x6-translucent': Specifies the ISO A3X6 translucent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x7-white': Specifies the ISO A3X7 white medium having the
      width of the longer edge (420 mm) of the ISO A3 medium
 'iso-a3x7-transparent': Specifies the ISO A3X7 transparent medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a3x7-translucent'': Specifies the ISO A3X7 translucent' medium
      having the width of the longer edge (420 mm) of the ISO A3
      medium
 'iso-a4x3-white': Specifies the ISO A4X3 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x3-transparent': Specifies the ISO A4X3 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x3-translucent'': Specifies the ISO A4X3 translucent' medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x4-white': Specifies the ISO A4X4 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x4-transparent': Specifies the ISO A4X4 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x4-translucent': Specifies the ISO A4X4 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x5-white': Specifies the ISO A4X5 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x5-transparent': Specifies the ISO A4X5 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x5-translucent': Specifies the ISO A4X5 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x6-white': Specifies the ISO A4X6 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x6-transparent': Specifies the ISO A4X6 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x6-translucent': Specifies the ISO A4X6 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x7-white': Specifies the ISO A4X7 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x7-transparent': Specifies the ISO A4X7 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x7-translucent': Specifies the ISO A4X7 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x8-white': Specifies the ISO A4X8 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x8-transparent': Specifies the ISO A4X8 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x8-translucent': Specifies the ISO A4X8 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x9-white': Specifies the ISO A4X9 white medium having the
      width of the longer edge (297 mm) of the ISO A4 medium
 'iso-a4x9-transparent': Specifies the ISO A4X9 transparent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium
 'iso-a4x9-translucent': Specifies the ISO A4X9 translucent medium
      having the width of the longer edge (297 mm) of the ISO A4
      medium

The following standard values are defined for Japanese and European Standard (i.e. ISO) engineering media, which are either a long fixed size [ASME-Y14.1M] or roll feed, for devices that provide the "synchro-cut" feature (see section 14.1):

'iso-a0xsynchro-white': Specifies the paper having the width of the: longer edge (1189 mm) of the ISO A0 white medium and cuts synchronizing with data.

 'iso-a0xsynchro-transparent': Specifies the paper having the width of
      the longer edge (1189 mm) of the ISO A0 transparent medium and
      cuts synchronizing with data.
 'iso-a0xsynchro-translucent': Specifies the paper having the width of
      the longer edge (1189 mm) of the ISO A0 translucent medium and
      cuts synchronizing with data.
 'iso-a1xsynchro-white': Specifies the paper having the width of the
      longer edge (841 mm) of the ISO A1 white medium and cuts
      synchronizing with data.
 'iso-a1xsynchro-transparent': Specifies the paper having the width of
      the longer edge (841 mm) of the ISO A1 transparent medium and
      cuts synchronizing with data.
 'iso-a1xsynchro-translucent': Specifies the paper having the width of
      the longer edge (841 mm) of the ISO A1 translucent medium and
      cuts synchronizing with data.
 'iso-a2xsynchro-white': Specifies the paper having the width of the
      longer edge (594 mm) of the ISO A2 white medium and cuts
      synchronizing with data.
 'iso-a2xsynchro-transparent': Specifies the paper having the width of
      the longer edge (594 mm) of the ISO A2 transparent medium and
      cuts synchronizing with data.
 'iso-a2xsynchro-translucent': Specifies the paper having the width of
      the longer edge (594 mm) of the ISO A2 translucent medium and
      cuts synchronizing with data.
 'iso-a3xsynchro-white': Specifies the paper having the width of the
      longer edge (420 mm) of the ISO A3 white medium and cuts
      synchronizing with data.
 'iso-a3xsynchro-transparent': Specifies the paper having the width of
      the longer edge (420 mm) of the ISO A3 transparent medium and
      cuts synchronizing with data.
 'iso-a3xsynchro-translucent': Specifies the paper having the width of
      the longer edge (420 mm) of the ISO A3 translucent medium and
      cuts synchronizing with data.
 'iso-a4xsynchro-white': Specifies the paper having the width of the
      longer edge (297 mm) of the ISO A4 white medium and cuts
      synchronizing with data.
 'iso-a4xsynchro-transparent': Specifies the paper having the width of
      the longer edge (297 mm) of the ISO A4 transparent medium and
      cuts synchronizing with data.
 'iso-a4xsynchro-translucent': Specifies the paper having the width of
      the longer edge (297 mm) of the ISO A4 transparent medium and
      cuts synchronizing with data.

The following standard values are defined for American Standard (i.e. ANSI) engineering media, American Architectural engineering media, and Japanese and European Standard (i.e. ISO) engineering media, which are either a long fixed size [ASME-Y14.1M] or roll feed, for devices that provide the "synchro-cut" feature and/or the "auto- select" feature (see section 14.1):

 'auto-white': Specifies that the printer selects the white medium
      with the appropriate fixed size (e.g. a1, a2, etc.) or data-
      synchro size, and the selection is implementation-defined.
 'auto-transparent': Specifies that the printer selects the
      transparent medium with the appropriate fixed size (e.g. a1, a2,
      etc.) or data-synchro size, and the selection is implementation-
      defined.
 'auto-translucent': Specifies that the printer selects the
      translucent medium with the appropriate fixed size (e.g. a1, a2,
      etc.) or data-synchro size, and the selection is implementation-
      defined.
 'auto-fixed-size-white': Specifies that the printer selects the white
      medium with the appropriate fixed size (e.g. a1, a2, etc.) or
      the appropriate long fixed size listed above.
 'auto-fixed-size-transparent': Specifies that the printer selects the
      transparent medium with the appropriate fixed size (e.g. a1, a2,
      etc.) or the appropriate long fixed size listed above.
 'auto-fixed-size-translucent': Specifies that the printer selects the
      translucent medium with the appropriate fixed size (e.g. a1, a2,
      etc.) or the appropriate long fixed size listed above.
 'auto-synchro-white': Specifies that the printer selects the white
      paper with the appropriate width and cuts it synchronizing with
      data.
 'auto-synchro-transparent': Specifies that the printer selects the
      transparent paper with the appropriate width and cuts it
      synchronizing with data.
 'auto-synchro-translucent': Specifies that the printer selects the
      translucent paper with the appropriate width and cuts it
      synchronizing with data.

The following standard values are defined for input-trays (from ISO DPA and the Printer MIB):

'top': The top input tray in the printer.
'middle': The middle input tray in the printer.
'bottom': The bottom input tray in the printer.
'envelope': The envelope input tray in the printer.
'manual': The manual feed input tray in the printer. 'large-capacity': The large capacity input tray in the printer. 'main': The main input tray
'side': The side input tray

The following standard values are defined for media sizes (from ISO DPA):

 'iso-a0': Specifies the ISO A0 size: 841 mm by 1189 mm as defined in
    ISO 216
 'iso-a1': Specifies the ISO A1 size: 594 mm by 841 mm as defined in
    ISO 216
 'iso-a2': Specifies the ISO A2 size: 420 mm by 594 mm as defined in
    ISO 216
 'iso-a3': Specifies the ISO A3 size: 297 mm by 420 mm as defined in
    ISO 216
 'iso-a4': Specifies the ISO A4 size: 210 mm by 297 mm as defined in
    ISO 216
 'iso-a5': Specifies the ISO A5 size: 148 mm by 210 mm as defined in
    ISO 216
 'iso-a6': Specifies the ISO A6 size: 105 mm by 148 mm as defined in
    ISO 216
 'iso-a7': Specifies the ISO A7 size: 74 mm by 105 mm as defined in
    ISO 216
 'iso-a8': Specifies the ISO A8 size: 52 mm by 74 mm as defined in ISO
    216
 'iso-a9': Specifies the ISO A9 size: 37 mm by 52 mm as defined in ISO
    216
 'iso-a10': Specifies the ISO A10 size: 26 mm by 37 mm as defined in
    ISO 216
 'iso-b0': Specifies the ISO B0 size: 1000 mm by 1414 mm as defined in
    ISO 216
 'iso-b1': Specifies the ISO B1 size: 707 mm by 1000 mm as defined in
    ISO 216
 'iso-b2': Specifies the ISO B2 size: 500 mm by 707 mm as defined in
    ISO 216
 'iso-b3': Specifies the ISO B3 size: 353 mm by 500 mm as defined in
    ISO 216
 'iso-b4': Specifies the ISO B4 size: 250 mm by 353 mm as defined in
    ISO 216
 'iso-b5': Specifies the ISO B5 size: 176 mm by 250 mm as defined in
    ISO 216
 'iso-b6': Specifies the ISO B6 size: 125 mm by 176 mm as defined in
    ISO 216
 'iso-b7': Specifies the ISO B7 size: 88 mm by 125 mm as defined in
    ISO 216
 'iso-b8': Specifies the ISO B8 size: 62 mm by 88 mm as defined in ISO
    216
 'iso-b9': Specifies the ISO B9 size: 44 mm by 62 mm as defined in ISO
    216
 'iso-b10': Specifies the ISO B10 size: 31 mm by 44 mm as defined in
    ISO 216
 'na-letter': Specifies the North American letter size: 8.5 inches by
    11 inches
 'na-legal': Specifies the North American legal size: 8.5 inches by 14
    inches
 'na-8x10': Specifies the North American 8 inches by 10 inches
 'na-5x7': Specifies the North American 5 inches by 7 inches
 'executive': Specifies the executive size (7.25 X 10.5 in)
 'folio': Specifies the folio size (8.5 X 13 in)
 'invoice': Specifies the invoice size (5.5 X 8.5 in)
 'ledger': Specifies the ledger size (11 X 17 in)
 'quarto': Specifies the quarto size (8.5 X 10.83 in)
 'iso-c3': Specifies the ISO C3 size: 324 mm by 458 mm as defined in
    ISO 269
 'iso-c4': Specifies the ISO C4 size: 229 mm by 324 mm as defined in
    ISO 269
 'iso-c5': Specifies the ISO C5 size: 162 mm by 229 mm as defined in
    ISO 269
 'iso-c6': Specifies the ISO C6 size: 114 mm by 162 mm as defined in
    ISO 269
 'iso-designated-long': Specifies the ISO Designated Long size: 110 mm
    by 220 mm as defined in ISO 269
 'na-10x13-envelope': Specifies the North American 10x13 size: 10
    inches by 13 inches
 'na-9x12-envelope': Specifies the North American 9x12 size: 9 inches
    by 12 inches
 'na-number-10-envelope': Specifies the North American number 10
    business envelope size: 4.125 inches by 9.5 inches
 'na-7x9-envelope': Specifies the North American 7x9 inch envelope
    size
 'na-9x11-envelope': Specifies the North American 9x11 inch envelope
    size
 'na-10x14-envelope': Specifies the North American 10x14 inch envelope
    size
 'na-number-9-envelope': Specifies the North American number 9
    business envelope size
 'na-6x9-envelope': Specifies the North American 6x9 envelope size
 'na-10x15-envelope': Specifies the North American 10x15 envelope size
 'monarch-envelope': Specifies the Monarch envelope size (3.87 x 7.5
    in)
 'jis-b0': Specifies the JIS B0 size: 1030mm x 1456mm
 'jis-b1': Specifies the JIS B1 size: 728mm x 1030mm
 'jis-b2': Specifies the JIS B2 size: 515mm x 728mm
 'jis-b3': Specifies the JIS B3 size: 364mm x 515mm
 'jis-b4': Specifies the JIS B4 size: 257mm x 364mm
 'jis-b5': Specifies the JIS B5 size: 182mm x 257mm
 'jis-b6': Specifies the JIS B6 size: 128mm x 182mm
 'jis-b7': Specifies the JIS B7 size: 91mm x 128mm
 'jis-b8': Specifies the JIS B8 size: 64mm x 91mm

'jis-b9': Specifies the JIS B9 size: 45mm x 64mm
'jis-b10': Specifies the JIS B10 size: 32mm x 45mm

The following standard values are defined for American Standard (i.e. ANSI) engineering media sizes:

    'a': Specifies the engineering ANSI A size medium: 8.5 inches x 11
       inches
    'b': Specifies the engineering ANSI B size medium: 11 inches x 17
       inches
    'c': Specifies the engineering ANSI C size medium: 17 inches x 22
       inches
    'd': Specifies the engineering ANSI D size medium: 22 inches x 34
       inches
    'e': Specifies the engineering ANSI E size medium: 34 inches x 44
       inches

The following standard values are defined for American Architectural engineering media sizes:

    'arch-a': Specifies the Architectural A size medium: 9 inches x 12
       inches
    'arch-b': Specifies the Architectural B size medium: 12 inches x 18
       inches
    'arch-c': Specifies the Architectural C size medium: 18 inches x 24
       inches
    'arch-d': Specifies the Architectural D size medium: 24 inches x 36
       inches
    'arch-e': Specifies the Architectural E size medium: 36 inches x 48
       inches

14.1. Examples

Below are examples to supplement the engineering media value definitions.

   Example 1:  "Synchro-Cut", a device cutting the roll paper in
   synchronization with the data
   
     data height:          A1 height
     data width (shaded):  A1 width < data width < (A1 width) x 2
     specified value:      'iso-a1xsynchro-white'

               |                    |
               |<--- data width --->|
               |                    |
               |              |     |        |
               |<- A1 width ->|<- A1 width ->|
               |              |     |        |
     cross  ^  |              |     |        |
      feed  |  +--------------------------------------------/
 direction  |  |//////////////|/////|        |     ^       /
            |  |//////////////|/////|        |     |      /
            |  |//////////////|/////|        |     |     /
            |  |//////////////|/////|        |     |     \
<-----------+- |//////////////|/////|        |    A1      \  roll
feed        |  |//////////////|/////|        |   height    \  paper
direction      |//////////////|/////|        |     |        \
               |//////////////|/////|        |     |        /
               |//////////////|/////|        |     v       /
               +------------------------------------------/
                                    |
                                    |
                                    |<------ CUT HERE (to synchronize
                                    |                with data width)
                                    |

Example 2: "Auto-Cut", a device cutting the roll paper at multiples of fixed-size media width

     data height:          A1 height
     data width (shaded):  A1 width < data width < (A1 width) x 2
     specified value:      'auto-fixed-size-white'

                 |                    |
                 |<--- data width --->|
                 |                    |
                 |              |     |        |
                 |<- A1 width ->|<- A1 width ->|
                 |              |     |        |
     cross  ^    |              |     |        |
      feed  |    +--------------------------------------------/
 direction  |    |//////////////|/////|        |     ^       /
            |    |//////////////|/////|        |     |      /
            |    |//////////////|/////|        |     |     /
            |    |//////////////|/////|        |     |     \
<-----------+-   |//////////////|/////|        |    A1      \  roll
feed        |    |//////////////|/////|        |   height    \  paper
direction        |//////////////|/////|        |     |        \
                 |//////////////|/////|        |     |        /
                 |//////////////|/////|        |     v       /
                 +------------------------------------------/
                                               |
                                               |
                                               |<--- CUT HERE
                                               |      (to synchronize
                                               |       with data width)
   Example 3:  the 'iso-a4x4-white' fixed size paper

     paper height:         A4 height
     paper width:          (A4 width) x 4
     specified value:      'iso-a4x4-white'

   |              |              |              |              |
   |<- A4 width ->|<- A4 width ->|<- A4 width ->|<- A4 width ->|
   |              |              |              |              |
   |              |              |              |              |
   +-----------------------------------------------------------+
   |       ^      |              |              |              |
   |       |      |              |              |              |
   |       |      |              |              |              |
   |      A4      |              |              |              |
   |    height    |              |              |              |
   |       |      |              |              |              |
   |       |      |              |              |              |
   |       |      |              |              |              |
   |       v      |              |              |              |
   +-----------------------------------------------------------+

Example 4: "Synchro-Cut", a device cutting the fixed size paper in synchronization with the data

     data height:          A4 height
     data width (shaded):  (A4 width) x 2 < data width < (A4 width) x 3
     specified value:      'iso-a4xsynchro-white'
   
                    |                                   |
                    |<---------- data width ----------->|
                    |                                   |
                    |              |              |     |        |
                    |<- A4 width ->|<- A4 width ->|<- A4 width ->|
                    |              |              |     |        |
        cross  ^    |              |              |     |        |
         feed  |    +--------------------------------------------+
    direction  |    |//////////////|//////////////|/////|    ^   |
               |    |//////////////|//////////////|/////|    |   |
               |    |//////////////|//////////////|/////|    |   |
               |    |//////////////|//////////////|/////|    |   |
   <-----------+-   |//////////////|//////////////|/////|   A4   |
   feed        |    |//////////////|//////////////|/////| height |
   direction        |//////////////|//////////////|/////|    |   |
                    |//////////////|//////////////|/////|    |   |
                    |//////////////|//////////////|/////|    v   |
                    +--------------------------------------------+
                                                        |
                                          CUT HERE ---->|
                                    (to synchronize     |
                                    with data width)    |

15. APPENDIX D: Processing IPP Attributes

When submitting a print job to a Printer object, the IPP model allows a client to supply operation and Job Template attributes along with the document data. These Job Template attributes in the create request affect the rendering, production and finishing of the documents in the job. Similar types of instructions may also be contained in the document to be printed, that is, embedded within the print data itself. In addition, the Printer has a set of attributes that describe what rendering and finishing options which are supported by that Printer. This model, which allows for flexibility and power, also introduces the potential that at job submission time, these client-supplied attributes may conflict with either:

      - what the implementation is capable of realizing (i.e., what the
        Printer supports), as well as
      - the instructions embedded within the print data itself.

The following sections describe how these two types of conflicts are handled in the IPP model.

15.1 Fidelity

If there is a conflict between what the client requests and what a Printer object supports, the client may request one of two possible conflict handling mechanisms:

      1) either reject the job since the job can not be processed
         exactly as specified, or
      2) allow the Printer to make any changes necessary to proceed with
         processing the Job the best it can.

In the first case the client is indicating to the Printer object: "Print the job exactly as specified with no exceptions, and if that can't be done, don't even bother printing the job at all." In the second case, the client is indicating to the Printer object: "It is more important to make sure the job is printed rather than be processed exactly as specified; just make sure the job is printed even if some client-supplied attributes need to be changed or ignored."

The IPP model accounts for this situation by introducing an "ipp- attribute-fidelity" attribute.

In a create request, "ipp-attribute-fidelity" is a boolean operation attribute that is OPTIONALLY supplied by the client. The value 'true' indicates that total fidelity to client supplied Job Template attributes and values is required. The client is requesting that the Job be printed exactly as specified, and if that is not possible then the job MUST be rejected rather than processed incorrectly. The value 'false' indicates that a reasonable attempt to print the Job is acceptable. If a Printer does not support some of the client supplied Job Template attributes or values, the Printer MUST ignore them or substitute any supported value for unsupported values, respectively. The Printer may choose to substitute the default value associated with that attribute, or use some other supported value that is similar to the unsupported requested value. For example, if a client supplies a "media" value of 'na-letter', the Printer may choose to substitute 'iso-a4' rather than a default value of 'envelope'. If the client does not supply the "ipp-attribute- fidelity" attribute, the Printer assumes a value of 'false'.

Each Printer implementation MUST support both types of "fidelity" printing (that is whether the client supplies a value of 'true' or 'false'):

      - If the client supplies 'false' or does not supply the attribute,
        the Printer object MUST always accept the request by ignoring
        unsupported Job Template attributes and by substituting
        unsupported values of supported Job Template attributes with
        supported values.
      - If the client supplies 'true', the Printer object MUST reject
        the request if the client supplies unsupported Job Template
        attributes.

Since a client can always query a Printer to find out exactly what is and is not supported, "ipp-attribute-fidelity" set to 'false' is useful when:

      1) The End-User uses a command line interface to request
         attributes that might not be supported.
      2) In a GUI context, if the End User expects the job might be
         moved to another printer and prefers a sub-optimal result to
         nothing at all.
      3) The End User just wants something reasonable in lieu of nothing
         at all.

15.2 Page Description Language (PDL) Override

If there is a conflict between the value of an IPP Job Template attribute and a corresponding instruction in the document data, the value of the IPP attribute SHOULD take precedence over the document instruction. Consider the case where a previously formatted file of document data is sent to an IPP Printer. In this case, if the client supplies any attributes at job submission time, the client desires that those attributes override the embedded instructions. Consider the case were a previously formatted document has embedded in it commands to load 'iso-a4' media. However, the document is passed to an end user that only has access to a printer with 'na-letter' media loaded. That end user most likely wants to submit that document to an IPP Printer with the "media" Job Template attribute set to 'na- letter'. The job submission attribute should take precedence over the embedded PDL instruction. However, until companies that supply document data interpreters allow a way for external IPP attributes to take precedence over embedded job production instructions, a Printer might not be able to support the semantics that IPP attributes override the embedded instructions.

The IPP model accounts for this situation by introducing a "pdl- override-supported" attribute that describes the Printer objects capabilities to override instructions embedded in the PDL data stream. The value of the "pdl-override-supported" attribute is configured by means outside the scope of this IPP/1.1 document.

This REQUIRED Printer attribute takes on the following values:

      - 'attempted': This value indicates that the Printer object
        attempts to make the IPP attribute values take precedence over
        embedded instructions in the document data, however there is no
        guarantee.
      - 'not-attempted': This value indicates that the Printer object
        makes no attempt to make the IPP attribute values take
        precedence over embedded instructions in the document data.

At job processing time, an implementation that supports the value of 'attempted' might do one of several different actions:

      1) Generate an output device specific command sequence to realize
         the feature represented by the IPP attribute value.
      2) Parse the document data itself and replace the conflicting
         embedded instruction with a new embedded instruction that
         matches the intent of the IPP attribute value.
      3) Indicate to the Printer that external supplied attributes take
         precedence over embedded instructions and then pass the
         external IPP attribute values to the document data interpreter.
      4) Anything else that allows for the semantics that IPP attributes
         override embedded document data instructions.

Since 'attempted' does not offer any type of guarantee, even though a given Printer object might not do a very "good" job of attempting to ensure that IPP attributes take a higher precedence over instructions embedded in the document data, it would still be a conforming implementation.

At job processing time, an implementation that supports the value of 'not-attempted' might do one of the following actions:

Simply pre-pend the document data with the PDL instruction that corresponds to the client-supplied PDL attribute, such that if the document data also has the same PDL instruction, it will override what the Printer object pre-pended. In other words, this implementation is using the same implementation semantics for the client-supplied IPP attributes as for the Printer object defaults.

Parse the document data and replace the conflicting embedded instruction with a new embedded instruction that approximates, but does not match, the semantic intent of the IPP attribute value.

   Note:  The "ipp-attribute-fidelity" attribute applies to the
   Printer's ability to either accept or reject other unsupported Job

Template attributes. In other words, if "ipp-attribute-fidelity" is set to 'true', a Job is accepted if and only if the client supplied Job Template attributes and values are supported by the Printer. Whether these attributes actually affect the processing of the Job when the document data contains embedded instructions depends on the ability of the Printer to override the instructions embedded in the document data with the semantics of the IPP attributes. If the document data attributes can be overridden ("pdl-override-supported" set to 'attempted'), the Printer makes an attempt to use the IPP attributes when processing the Job. If the document data attributes can not be overridden ("pdl-override-supported" set to 'not- attempted'), the Printer makes no attempt to override the embedded document data instructions with the IPP attributes when processing the Job, and hence, the IPP attributes may fail to affect the Job processing and output when the corresponding instruction is embedded in the document data.

15.3 Using Job Template Attributes During Document Processing.

The Printer object uses some of the Job object's Job Template attributes during the processing of the document data associated with that job. These include, but are not limited to, "orientation- requested", "number-up", "sides", "media", and "copies". The processing of each document in a Job Object MUST follow the steps below. These steps are intended only to identify when and how attributes are to be used in processing document data and any alternative steps that accomplishes the same effect can be used to implement this specification document.

Using the client supplied "document-format" attribute or some form of document format detection algorithm (if the value of "document-format" is not specific enough), determine whether or not the document data has already been formatted for printing. If the document data has been formatted, then go to step 2. Otherwise, the document data MUST be formatted. The formatting detection algorithm is implementation defined and is not specified by this document. The formatting of the document data uses the "orientation-requested" attribute to determine how the formatted print data should be placed on a print-stream page, see section 4.2.10 for the details.

The document data is in the form of a print-stream in a known media type. The "page-ranges" attribute is used to select, as specified in section 4.2.7, a sub-sequence of the pages in the print-stream that are to be processed and images.

The input to this step is a sequence of print-stream pages. This step is controlled by the "number-up" attribute. If the value of "number-up" is N, then during the processing of the print-stream pages, each N print-stream pages are positioned, as specified in section 4.2.9, to create a single impression. If a given document does not have N more print-stream pages, then the completion of the impression is controlled by the "multiple-document-handling" attribute as described in section 4.2.4; when the value of this attribute is 'single-document' or 'single-document-new-sheet', the print-stream pages of document data from subsequent documents is used to complete the impression.

The size(scaling), position(translation) and rotation of the print-stream pages on the impression is implementation defined. Note that during this process the print-stream pages may be rendered to a form suitable for placing on the impression; this rendering is controlled by the values of the "printer- resolution" and "print-quality" attributes as described in sections 4.2.12 and 4.2.13. In the case N=1, the impression is nearly the same as the print-stream page; the differences would only be in the size, position and rotation of the print-stream page and/or any decoration, such as a frame to the page, that is added by the implementation.

The collection of impressions is placed, in sequence, onto sides of the media sheets. This placement is controlled by the "sides" attribute and the orientation of the print-stream page, as described in section 4.2.8. The orientation of the print- stream pages affects the orientation of the impression; for example, if "number-up" equals 2, then, typically, two portrait print-stream pages become one landscape impression. Note that the placement of impressions onto media sheets is also controlled by the "multiple-document-handling" attribute as described in section 4.2.4.

The "copies" and "multiple-document-handling" attributes are used to determine how many copies of each media instance are created and in what order. See sections 4.2.5 and 4.2.4 for the details.

When the correct number of copies are created, the media instances are finished according to the values of the "finishings" attribute as described in 4.2.6. Note that sometimes finishing operations may require manual intervention to perform the finishing operations on the copies, especially uncollated copies. This document allows any or all of the processing steps to be performed automatically or manually at the discretion of the Printer object.

16. APPENDIX E: Generic Directory Schema

This section defines a generic schema for an entry in a directory service. A directory service is a means by which service users can locate service providers. In IPP environments, this means that IPP Printers can be registered (either automatically or with the help of an administrator) as entries of type printer in the directory using an implementation specific mechanism such as entry attributes, entry type fields, specific branches, etc. Directory clients can search or browse for entries of type printer. Clients use the directory service to find entries based on naming, organizational contexts, or filtered searches on attribute values of entries. For example, a client can find all printers in the "Local Department" context. Authentication and authorization are also often part of a directory service so that an administrator can place limits on end users so that they are only allowed to find entries to which they have certain access rights. IPP itself does not require any specific directory service protocol or provider.

Note: Some directory implementations allow for the notion of "aliasing". That is, one directory entry object can appear as multiple directory entry object with different names for each object. In each case, each alias refers to the same directory entry object which refers to a single IPP Printer object.

The generic schema is a subset of IPP Printer Job Template and Printer Description attributes (sections 4.2 and 4.4). These attributes are identified as either RECOMMENDED or OPTIONAL for the directory entry itself. This conformance labeling is NOT the same conformance labeling applied to the attributes of IPP Printers objects. The conformance labeling in this Appendix is intended to apply to directory templates and to IPP Printer implementations that subscribe by adding one or more entries to a directory. RECOMMENDED attributes SHOULD be associated with each directory entry. OPTIONAL attributes MAY be associated with the directory entry (if known or supported). In addition, all directory entry attributes SHOULD reflect the current attribute values for the corresponding Printer object.

The names of attributes in directory schema and entries SHOULD be the same as the IPP Printer attribute names as shown, as much as possible.

In order to bridge between the directory service and the IPP Printer object, one of the RECOMMENDED directory entry attributes is the Printer object's "printer-uri-supported" attribute. The directory client queries the "printer-uri-supported" attribute (or its equivalent) in the directory entry and then the IPP client addresses the IPP Printer object using one of its URIs. The "uri-security- supported" attribute identifies the protocol (if any) used to secure a channel.

The following attributes define the generic schema for directory entries of type PRINTER:

     printer-uri-supported              RECOMMENDED    Section 4.4.1
     uri-authentication-supported       RECOMMENDED    Section 4.4.2
     uri-security-supported             RECOMMENDED    Section 4.4.3
     printer-name                       RECOMMENDED    Section 4.4.4
     printer-location                   RECOMMENDED    Section 4.4.5
     printer-info                       OPTIONAL       Section 4.4.6
     printer-more-info                  OPTIONAL       Section 4.4.7
     printer-make-and-model             RECOMMENDED    Section 4.4.9
     ipp-versions-supported             RECOMMENDED    Section 4.4.14
     multiple-document-jobs-supported   OPTIONAL       Section 4.4.16
     charset-supported                  OPTIONAL       Section 4.4.18
     
     generated-natural-language-
        supported                       OPTIONAL       Section 4.4.20
     document-format-supported          RECOMMENDED    Section 4.4.22
     color-supported                    RECOMMENDED    Section 4.4.26
     compression-supported              RECOMMENDED    Section 4.4.32
     pages-per-minute                   OPTIONAL       Section 4.4.36
     pages-per-minute-color             OPTIONAL       Section 4.4.37
     
     finishings-supported               OPTIONAL       Section 4.2.6
     number-up-supported                OPTIONAL       Section 4.2.7
     sides-supported                    RECOMMENDED    Section 4.2.8
     media-supported                    RECOMMENDED    Section 4.2.11
     printer-resolution-supported       OPTIONAL       Section 4.2.12
     print-quality-supported            OPTIONAL       Section 4.2.13

17. APPENDIX F: Differences between the IPP/1.0 and IPP/1.1 "Model and

Semantics" Documents

This Appendix is divided into two lists that summarize the differences between IPP/1.1 (this document) and IPP/1.0 [RFC2566]. The section numbers refer to the numbers in this document which in some cases have changed from RFC 2566. When a change affects multiple sections, the item is listed once in the order of the first section affected and the remaining affected section numbers are indicated.

The first list contains extensions and clarifications and the second list contains changes in semantics or conformance. However, client and IPP object implementations of IPP/1.0 MAY implement any of the extensions and clarifications in this document.

The following extensions and clarifications have been incorporated into this document:

      1.  Section 2.1 - clarified that the term "client" can be either
          contained in software controlled by an end user or a part of a
          print server that controls devices.
      2.  Section 2 - clarified that the term "IPP object" and "Printer
          object" can either be embedded in a device object or part of a
          print server that accepts IPP requests.
      3.  Section 2.4 - added the description of the new "uri-
          authentication-supported" Printer Description attribute.
      4.  Section 3.1.3, 3.1.6, 3.2.5.2, and 3.2.6.2 - clarified the
          error handling for operation attributes that have their own
          status code.
      5.  Section 3.1.3 - clarified that multiple occurrences of the
          same attribute in an attribute group is mal-formed.  An IPP
          Printer MAY reject the request or choose one of the
          attributes.
      6.  Section 3.1.6 - reorganized this section into sub-sections to
          separately describe "status-code", "status-message",
          "detailed-status-message", and "document-access-error"
          attributes.
      7.  Section 3.1.6.1 - clarified the error status codes and their
          relationship to operation attributes.
      8.  Section 3.1.6.3 - Added the OPTIONAL "detailed-status-message
          (text(MAX))" operation attribute to provide additional more
          detailed information about a response.
      9.  Section 3.1.6.4 and 3.2.2 - Added the OPTIONAL "document-
          access-error (text(MAX))" operation attribute for use with
          Print-URI and Send-URI responses.
      10. Sections 3.1.7 - Added this new section to clarify returning
          Unsupported Attributes for all operations, including only
          returning attributes that were in the request.  Moved the text
          from section 3.2.1.2 Unsupported Attributes to this section.
      11. Sections 3.1.7 and 4.1 - clarified the encoding of the "out-
          of-band" 'unsupported' and 'unknown' values.
      12. Section 3.1.8 - clarified that only the version number
          parameter will be carried forward into future major or minor
          versions of the protocol.
      13. Section 3.1.8 - relaxed the requirements to increment the
          major version number in future versions of the Model and
          Semantics document.
      14. Section 3.1.9, and 3.2.5 - added the 'processing' state to the
          list of job states that a job can be in after a Create-Job
          operation.
      15. Section 3.1.9 - clarified that a non-spooling Printer MAY
          accept zero or more subsequent jobs while processing a job and
          flow control them down.  Subsequent create requests are
          rejected with the 'server-error-busy' error status.
      16. Section 3.2.1.1 - clarified the validation of the
          "compression" operation attribute and its relationship to the
          validation of the "document-format" attribute and returning
          Unsupported Attributes.
      17. Sections 3.2.1.1, 4.3.8, 13.1.4.16, and 13.1.4.17 - added the
          'client-error-compression-not-supported', 'client-error-
          compression-error' status codes and the 'unsupported-
          compression' and 'compression-error' job-state-reasons.
      18. Sections 3.2.1.1 and 4.3.8 - added 'unsupported-document-
          format' and 'document-format-error' job-state-reasons.
      19. Sections 3.2.2, 4.3.8 and 13.1.4.19 - added 'client-error-
          document-access-error' status code and 'document-access-error'
          job state reason.
      20. Section 3.2.5.2 and 3.2.6.2 - clarified that the Unsupported
          Attributes group MUST NOT include attributes not requested in
          the Get-Printer-Attributes request.
      21. Section 3.2.6 - clarified that "limit" takes precedence over
          "which-jobs" and "my-jobs'.
      22. Section 3.2.6.2 - clarified that Get-Jobs returns
          'successful-ok' when no jobs to return.
      23. Sections 3.2.7, 3.2.8, and 3.2.9 - added the OPTIONAL Pause-
          Printer, Resume-Printer, and Purge-Jobs operations
      24. Section 3.3.1  - clarified that the authorization required for
          a Send-Document request MUST be the same user as the Create-
          Job or an operator.
      25. Section 3.3.1.1 - clarified that a Create-Job Send-Document
          with "last-document" = 'true' and no data is not an error; its
          a job with no documents.
      26. Sections 3.3.5, 3.3.6, and 3.3.7 - added the OPTIONAL Hold-
          Job, Release-Job, and Restart-Job operations.  Clarified the
          Restart-Job operation so that the Printer MUST re-fetch any
          documents passed by-reference (Print-URI or Send-URI).
      27. Section 4.1 - clarified that the encoding of the out-of-band
          values are specified in the Encoding and Transport" document.
      28. Section 4.1 - Clarified that the requirement that clients MUST
          NOT send "out-of-band" values in requests applies only to
          operations defined in this document.  Other operations are
          allowed to define "out-of-band" values that clients can
          supply.
      29. Sections 4.1.1 and 4.1.2 - clarified that the maximum 'text'
          and 'name' values of 1023 and 255 are for the
          'textWithoutLanguage' portion of the 'textWithLanguage' form,
          so that the maximum number of octets for the actual text and
          name data is the same for the without and with language forms;
          the 'naturalLanguage' part is in addition.
      30. Section 4.1.9 - clarified that 'mimeMediaType' values can
          include any parameters from the IANA Registry, not just
          charset parameters.
      31. Section 4.1.9.1 - clarified that 'application/octet-stream'
          auto-sensing can happen at create request time and/or
          job/document processing time.
      32. Section 4.1.9.1 - clarified that auto-sensing involves the
          Printer examining some number of octets of document data using
          an implementation-dependent method.
      33. Section 4.1.14 - clarified that the localization of dateTime
          by the client includes the time zone.
      34. Section 4.2 - clarified that xxx-supported have multiple
          keywords and/or names by adding parentheses to the table to
          give:  (1setOf (type3 keyword | name))
      35. Section 4.2.2 - added the 'indefinite' keyword value to the
          "job-hold-until" attribute for use with the create operations
          and Hold-Job and Restart-Job operations.
      36. Section 4.2.6 - added more enum values to the "finishings" Job
          Template attribute.
      37. Section 4.2.6 - clarified that the landscape definition is a
          rotation of the image with respect to the medium.
      38. Section 4.3.7 - added that a forwarding server that cannot get
          any job state MAY return the job's state as 'completed',
          provided that it also return the new 'queued-in-device' job
          state reason.
      39. Section 4.3.7.2 - added the Partitioning of Job States section
          to clarify the concepts of Job Retention, Job History, and Job
          Removal.
      40. Section 4.3.8 - added 'job-data-insufficient' job state reason
          to indicate whether sufficient data has arrived for the
          document to start to be processed.
      41. Section 4.3.8 - added 'document-access-error' job state reason
          to indicate an access error of any kind.
      42. Section 4.3.8 - added 'job-queued-for-marker' job state reason
          to indicate whether the job has completed some processing and
          is waiting for the marker.
      43. Section 4.3.8 - added 'unsupported-compression' and
          'compression-error' job state reasons to indicate compression
          not supported or compression processing error after the create
          has been accepted.
      44. Section 4.3.8 - added 'unsupported-document-format' and
          'document-format-error' job state reasons to indicate document
          not supported or document format processing error after the
          create has been accepted.
      45. Section 4.3.8 - added 'queued-in-device' job state reason to
          indicate that a job as been forwarded to a print system or
          device that does not provide any job status.
      46. Section 4.3.10 - added "job-detailed-status-messages (1setOf
          text(MAX)) for returning detailed error messages.
      47. Section 4.3.11 - added the "job-document-access-errors (1setOf
          text(MAX))
      48. Section 4.3.14.2 - clarified that the time recorded is the
          first time processing since the create operation or the
          Restart-Job operation.
      49. Section 4.3.14.2 and 4.3.14.3 - clarified that the out-of-band
          value 'no-value' is returned if the job has not started
          processing or has not completed, respectively.
      50. Section 4.3.14 - Added the OPTIONAL "date-time-at-creation",
          "date-time-at-processing", and "date-time-at-completed" Event
          Time Job Description attributes
      51. Section 4.4.3 - added the 'tls' value to "uri-security-
          supported" attribute.
      52. Section 4.4.3 - clarified "uri-security-supported" is
          orthogonal to Client Authentication so that 'none' does not
          exclude Client Authentication.
      53. Section 4.4.11 - simplified the "printer-state" descriptions
          while generalizing to allow high end devices that interpret
          one or more jobs while marking another.  Indicated that
          'spool-area-full' and 'stopped-partly' "printer-state-reasons"
          may be used to provide further state information.
      54. Section 4.4.12 - added the 'moving-to-paused' keyword value to
          the "printer-state-reasons" attribute for use with the Pause-
          Printer operation.
      55. Section 4.4.12 - replaced the duplicate 'marker-supply-low'
          keyword with the missing 'toner-empty' keyword for the
          "printer-state-reasons" attribute.  (This correction was also
          made before RFC 2566 was published).
      56. Section 4.4.12 - clarified 'spool-area-full' "printer-state-
          reasons" to include non-spooling printers to indicate when it
          can and cannot accept another job.
      57. Section 4.4.15 - added the enum values to the "operations-
          supported" attribute for the new operations.  Clarified that
          the values of this attribute are encoded as any enum, namely
          32-bit values.
      58. Section 4.4.30 - clarified that the dateTime value of
          "printer-current-time" is on a "best efforts basis".  If a
          proper date-time cannot be obtained, the implementation
          returns the 'no-value' out-of-band value.  Also clarified that
          the time zone NEED NOT be the time zone that the people near
          the device use and that the client SHOULD display the dateTime
          attributes in the user's local time.
      59. Sections 4.4.36 and 4.4.37 - added the OPTIONAL "pages-per-
          minute" and "pages-per-minute-color" Printer Description
          attributes.
      60. Section 5.1 - clarified that the client conformance
          requirements apply to clients controlled by an end user and
          clients in servers.
      61. Section 5.1 - clarified that any response MAY contain
          additional attribute groups, attributes, attribute syntaxes,
          or attribute values.
      62. Section 5.1 - clarified that a client SHOULD do its best to
          prevent a channel from being closed by a lower layer when the
          channel is flow controlled off by the IPP Printer.
      63. Section 5.2 - clarified that the IPP object requirements apply
          to objects embedded in devices or that are parts of servers.
      64. Section 5.2.2 - clarified that IPP objects MAY return
          operation responses that contain attribute groups, attribute
          names, attribute syntaxes, attribute values, and status codes
          that are extensions to this standard.
      65. Section 6 - changed the terminology of "private extensions" to
          "vendor extensions" and indicated that they are registered
          with IANA along with IETF standards track extensions.
      66. Section 6.7 - inserted this section on registering out-of-band
          attribute values with IANA as extensions.
      67. Section 8.3 - clarified the use of URIs for each Client
          Authentication mechanism.
      68. Section 8.5 - added the security discussion around the new
          operator/administrator operations.
      69. Section 13.1.4.16 - added client-error-compression-not-
          supported (0x040F)
      70. Section 13.1.4.17 - added client-error-compression-error
          (0x0410)
      71. Section 13.1.4.18 - added client-error-document-format-error
          (0x0411)
      72. Section 13.1.4.19 - added client-error-document-access-error
          (0x0412)
      73. Section 13.1.5.10 - added server-error-multiple-document-
          jobs-not-supported (0x0509)
      74. Section 14 - added 'a-white', 'b-white', 'c-white', 'd-white',
          and 'e-white' and clarified that the existing 'a', 'b', 'c',
          'd', and 'e' values are size values.  Added American,
          Japanese, and European Engineering sizes, filled out
          -transparent and - translucent media names and drawings for
          the synchro cut sizes.
      75. Section 16 - softened the RECOMMENDATION for IPP Printer
          attributes in a Directory schema so that they can have
          equivalents.
      76. Section 16 - added the OPTIONAL "pages-per-minute" and
          "pages-per-minute-color" Printer attributes to the Directory
          schema.
      77. Section 16 - added OPTIONAL "multiple-document-jobs-supported"
          to the Directory schema.
      78. Section 16 - added RECOMMENDED "uri-authentication-supported",
          "ipp-versions-supported", and "compression-supported" to the
          Directory schema.

The following changes in semantics and/or conformance have been incorporated into this document:

      1.  Section 3.1.6.3 - allowed a Printer to localize the
          "detailed-status-message" operation response attribute, but
          indicated that such localization might obscure the technical
          meaning of such messages.
      2.  Section 3.1.8, 5.2.4, and 13.1.5.4 - Clients and IPP objects
          MUST support version 1.1 conformance requirements.   It is
          recommended that they interoperate with 1.0.  Also clarified
          that IPP Printers MUST accept '1.1' requests.   It is
          recommended that they also accept '1.x' requests.
      
      3.  Section 3.2.1.1 and section 4.4.32 - changed the "compression"
          operation and the "compression-supported" Printer Description
          attribute from OPTIONAL to REQUIRED.
      4.  Sections 3.2.1.2 and 4.3.8 - changed "job-state-reasons" from
          RECOMMENDED to REQUIRED, so that "job-state-reasons" MUST be
          returned in create operation responses.
      5.  Sections 3.2.4, 3.3.1, 4.4.16, and 16 - changed Create-
          Job/Send-Document so that they MAY be implemented while only
          supporting one document jobs.  Added the "multiple-document-
          jobs-supported" boolean Printer Description attribute to
          indicate whether Create-Job/Send-Document support multiple
          document jobs or not.  Added to the Directory schema.
      6.  Section 4.1.9 - deleted 'text/plain; charset=iso-10646-ucs-2',
          since binary is not legal with the 'text' type.
      7.  Section 4.1.9.1 - added the RECOMMENDATION that a Printer
          indicate by printing on the job's job-start-sheet that auto-
          sensing has occurred and what document format was auto-sensed.
      8.  Section 4.2.4 - indicated that the "multiple-document-
          handling" Job Template attribute MUST be supported with at
          least one value if the Printer supports multiple documents per
          job
      9.  Section 4.3.7.2 - indicated that the 'job-restartable' job
          state reason SHOULD be supported if the Restart-Job operation
          is supported.
      10. Section 4.3.8 - changed "job-state-reasons" from RECOMMENDED
          to REQUIRED.
      11. Section 4.3.8 - clarified the conformance of the values of the
          "job-state-reasons" attribute by copying conformance
          requirements from other sections of the document so that it is
          clear from reading the definition of "job-state-reasons" which
          values MUST or SHOULD be supported.  The 'none',
          'unsupported-compression', and 'unsupported-document-format'
          values MUST be supported.  The 'job-hold-until-specified'
          SHOULD be specified if the "job-hold-until" Job Template is
          supported.  The following values SHOULD be supported:  'job-
          canceled-by-user', 'aborted-by-system', and 'job-completed-
          successfully'.  The
          'job-canceled-by-operator' SHOULD be supported if the
          implementation permits canceling by other than the job owner.
          The 'job-canceled-at-device' SHOULD be supported if the device
          supports canceling jobs at the console.  The 'job-completed-
          with-warnings' SHOULD be supported, if the implementation
          detects warnings.  The 'job-completed-with-errors' SHOULD be
          supported if the implementation detects errors.  The 'job-
          restartable' SHOULD be supported if the Restart-Job operation
          is supported.
      12. Section 4.3.10 - allowed a Printer to localize the "job-
          detailed-status-message" Job Description attribute, but
          indicated that such localization might obscure the technical
          meaning of such messages.
      13. Section 4.3.14 - changed the "time-at-creation", "time-at-
          processing", and "time-at-completed" Event Time Job
          Description attributes from OPTIONAL to REQUIRED.
      14. Section 4.3.14.4 - added the REQUIRED "job-printer-up-time
          (integer(1:MAX))" Job Description attribute as an alias for
          "printer-up-time" to reduce number of operations to get job
          times.
      15. Section 4.4.2 - added the REQUIRED "uri-authentication-
          supported (1setOf type2 keyword)" Printer Description
          attribute to describe the Client Authentication used by each
          Printer URI.
      16. Section 4.4.12 - changed "printer-state-reasons" Printer
          Description attribute from OPTIONAL to REQUIRED.
      17. Section 4.4.12 - changed 'paused' value of "printer-state-
          reasons" to MUST if Pause-Printer operation is supported.
      18. Section 4.4.14 - added the REQUIRED "ipp-versions-supported
          (1setOf keyword)" Printer Description attribute, since IPP/1.1
          Printers do not have to support version '1.0' conformance
          requirements.  Section 4.4.16 - added the "multiple-document-
          jobs-supported (boolean)" Printer Description attribute so
          that a client can tell whether a Printer that supports
          Create-Job/Send-Document supports multiple document jobs or
          not.  This attribute is REQUIRED if the Create-Job operation
          is supported.
      19. Section 4.4.24 - changed the "queued-job-count" Printer
          Description attribute from RECOMMENDED to REQUIRED.
      20. Section 4.4.32 - changed "compression-supported (1setOf type3
          keyword)" Printer Description attribute from OPTIONAL to
          REQUIRED.
      21. Section 5.1 - changed the client security requirements from
          RECOMMENDED non-standards track SSL3 to MUST support Client
          Authentication as defined in the IPP/1.1 Encoding and
          Transport document [RFC2910].  A client SHOULD support
          Operation Privacy and Server Authentication as defined in the
          IPP/1.1 Encoding and Transport document [RFC2910].
      22. Section 5.2.7 - changed the IPP object security requirements
          from OPTIONAL non-standards track SSL3 to SHOULD contain
          support for Client Authentication as defined in the IPP/1.1
          Encoding and Transport document [RFC2910].  A Printer
          implementation MAY allow an administrator to configure the
          Printer so that all, some, or none of the users are
          authenticated.  An IPP Printer implementation SHOULD contain
          support for Operation Privacy and Server Authentication as
          defined in the IPP/1.1 Encoding and Transport document
          [RFC2910].  A Printer implementation MAY allow an
          administrator to configure the degree of support for Operation
          Privacy and Server Authentication.  Security MUST NOT be
          compromised when the client supplies a lower version-number in
          a request.
      23. Section 14 (Appendix C): Corrected typo, changing the keyword
          'iso-10-white' to 'iso-a10-white'.
   
   See also the "IPP/1.1 Encoding and Transport" [RFC2910] document for
   differences between IPP/1.0 [RFC2565] and IPP/1.1 [RFC2910].

18. Full Copyright Statement

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Acknowledgement

Funding for the RFC Editor function is currently provided by the Internet Society.

Internet Printing Protocol/1.1: Model and Semantics

Status of this Memo

Copyright Notice

Abstract

Table of Contents

1. Introduction

1.1 Simplified Printing Model

2. IPP Objects

2.1 Printer Object

2.2 Job Object

2.3 Object Relationships

2.4 Object Identity

3. IPP Operations

3.1 Common Semantics

3.1.1 Required Parameters

3.1.2 Operation IDs and Request IDs

3.1.3 Attributes

3.1.4 Character Set and Natural Language Operation Attributes

3.1.4.1 Request Operation Attributes

Printer identified by the Printer object's "natural-language-

configured" attribute, though support of additional natural

languages for these attributes is permitted.

For example, the "job-name" attribute MAY be supplied by the

client in a create request. The text value for this attribute

will be in the natural language identified by the "attribute-

3.1.4.2 Response Operation Attributes

3.1.5 Operation Targets

3.1.6 Operation Response Status Codes and Status Messages

3.1.6.1 "status-code" (type2 enum)

3.1.6.2 "status-message" (text(255))

3.1.6.3 "detailed-status-message" (text(MAX))

3.1.6.4 "document-access-error" (text(MAX))

3.1.7 Unsupported Attributes

3.1.8 Versions

3.1.9 Job Creation Operations

3.2 Printer Operations

3.2.1 Print-Job Operation

3.2.1.1 Print-Job Request

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

3.2.1.2 Print-Job Response

3.2.2 Print-URI Operation

3.2.3 Validate-Job Operation

3.2.4 Create-Job Operation

3.2.5 Get-Printer-Attributes Operation

3.2.5.1 Get-Printer-Attributes Request

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

3.2.5.2 Get-Printer-Attributes Response

3.2.6 Get-Jobs Operation

3.2.6.1 Get-Jobs Request

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

3.2.6.2 Get-Jobs Response

3.2.7 Pause-Printer Operation

3.2.7.1 Pause-Printer Request

3.2.7.2 Pause-Printer Response

3.2.8 Resume-Printer Operation

3.2.9 Purge-Jobs Operation

3.3 Job Operations

3.3.1 Send-Document Operation

3.3.1.1 Send-Document Request

3.3.1.2 Send-Document Response

3.3.2 Send-URI Operation

3.3.3 Cancel-Job Operation

3.3.3.1 Cancel-Job Request

The "requesting-user-name" (name(MAX)) attribute SHOULD be

supplied by the client as described in section 8.3.

3.3.3.2 Cancel-Job Response

3.3.4 Get-Job-Attributes Operation

3.3.4.1 Get-Job-Attributes Request

3.3.4.2 Get-Job-Attributes Response

3.3.5 Hold-Job Operation

3.3.5.1 Hold-Job Request

3.3.5.2 Hold-Job Response

3.3.6 Release-Job Operation

Current "job- New "job-state" IPP object's response status

state" code and action:

3.3.7 Restart-Job Operation

Current "job- New "job-state" IPP object's response status