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Network Working Group T. Hastings,
Request for Comments: 2911 R.
Obsoletes: 2566 Xerox
Category: Standards Track R.
Utah Valley State
S.
Novell, Inc
P.
Astart
September 2000

Internet Printing Protocol/1.1: Model and

Status of this

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

Copyright

Copyright (C) The Internet Society (2000). All Rights Reserved

This document is one of a set of documents, which together
all aspects of a new Internet Printing Protocol (IPP). IPP is
application level protocol that can be used for distributed
using Internet tools and technologies. This document describes
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
supports multiple documents. IPP 1.1 semantics allow end-users
operators to query printer capabilities, submit print jobs,
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
addresses security, internationalization, and directory issues

Hastings, et al. Standards Track [Page 1]

RFC 2911 IPP/1.1: Model and Semantics September 2000

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

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

The "Internet Printing Protocol/1.1: Encoding and Transport"
is a formal mapping of the abstract operations and attributes
in the model document onto HTTP/1.1 [RFC2616]. It defines
encoding rules for a new Internet MIME media type
"application/ipp". This document also defines the rules
transporting over HTTP a message body whose Content-Type
"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"
gives insight and advice to implementers of IPP clients and
objects. It is intended to help them understand IPP/1.1 and some
the considerations that may assist them in the design of their
and/or IPP object implementations. For example, a typical order
processing requests is given, including error checking.
for some of the specification decisions is also included

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

Hastings, et al. Standards Track [Page 2]

RFC 2911 IPP/1.1: Model and Semantics September 2000

Table of

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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

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
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

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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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

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-
(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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

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
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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.2.1 successful-ok (0x0000) 178
13.1.2.2 successful-ok-ignored-or-substituted-
(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-
(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-
(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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

1.

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

Anyone reading these documents for the first time is
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
model for distributed printing
- Section 2 introduces the object types covered in the model
their basic behaviors, attributes, and interactions
- Section 3 defines the operations included in IPP/1.1.
operations are synchronous, therefore, for each operation, there
a both request and a response
- Section 4 defines the attributes (and their syntaxes) that are
in the model
- Sections 5 - 6 summarizes the implementation
requirements for objects that support the protocol and
considerations, respectively
- Sections 7 - 11 cover the Internationalization and
considerations as well as References, Author contact information
and Formats for Registration Proposals
- Sections 12 - 14 are appendices that cover Terminology,
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
in the model terminology section 12.2. Capitalized terms,
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
terminology, most of which is taken from RFC 2119 [RFC2119].

Hastings, et al. Standards Track [Page 9]

RFC 2911 IPP/1.1: Model and Semantics September 2000

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

1.1 Simplified Printing

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

The IPP/1.1 model encapsulates the important components
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).

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RFC 2911 IPP/1.1: Model and Semantics September 2000

It is important, however, to understand that in real
implementations (which lie underneath the abstracted IPP/1.1 model),
there are other components of a print service which are
explicitly defined in the IPP/1.1 model. The following
illustrates where IPP/1.1 fits with respect to these
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
C O T | --+
A R Y +--------+--------+ |
T Y | IPP Server | |
I +--------+--------+ |
O | |
N +-----------------+ | IPP
| Print Service | |
+-----------------+ |
| --+
+-----------------+
| Output Device(s)|
+-----------------+

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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

errors, warnings, and so forth, is directly associated with
Printer object itself rather than with the entry in the
which only represents the Printer object

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

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

A privileged operator or administrator of a Printer object
cancel, hold, release, and restart any user's job using the
Cancel-Job and the OPTIONAL Hold-Job, Release-Job, and Restart-
operations. In additional privileged operator or administrator of
Printer object can pause, resume, or purge (jobs from) a
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
register for and receive Printer specific and Job specific events
An end user can query the status of Printer objects and can
the progress of Job objects by polling using the Get-Printer
Attributes, Get-Jobs, and Get-Job-Attributes operations

2. IPP

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

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RFC 2911 IPP/1.1: Model and Semantics September 2000

and characteristics. For example, the Printer object type is
as a set of attributes that each Printer object potentially supports
In the same manner, the Job object type is defined as a set
attributes that are potentially supported by each Job object

Each attribute included in the set of attributes defining an
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
SHOULD support the value; otherwise, support of the value
OPTIONAL

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

2.1 Printer

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

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

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

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

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Some examples of configurations supporting a Printer object include

1) An output device with no spooling
2) An output device with a built-in
3) A print server supporting IPP with one or more
output
3a) The associated output devices may or may not be capable
spooling
3b) The associated output devices may or may not support

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

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

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

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

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

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

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

Legend

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

any indicates any network protocol or
connect, including

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embedded printer
output
+---------------+
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

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

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

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

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- "job-description" attributes: These attributes describe the
object's identification, state, size, etc. The client
some of these attributes, and the Printer object
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.
document is either

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

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

2.3 Object

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

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

A Job object is contained by exactly one Printer object, however
identical document data associated with a Job object could be sent
either the same or a different Printer object. In this case,
second Job object would be created which would be almost identical
the first Job object, however it would have new (different)
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
stream of document data, that stream can be contained in only
document. However, there can be identical copies of the stream
other documents in the same or different Job objects. If
contained document is just a reference to a stream of document data
other documents (in the same or different Job object(s)) may
the same reference

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2.4 Object

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

An administrator configures Printer objects to either support or
support authentication and/or message privacy using Transport
Security (TLS) [RFC2246] (the mechanism for security configuration
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
sort of negotiation mechanism. In other situations,
communication channels are used, one for each type of
configuration. Section 8 provides a full description of all
considerations and configurations

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

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

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

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

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

Allowing Job objects to have URIs allows for flexibility
scalability. For example, in some implementations, the
object might create Jobs that are processed in the same
environment as the Printer object itself. In this case, the Job
might just be a composition of the Printer's URI and some
component for the Job object, such as the unique 32-bit
integer mentioned later in this paragraph. In other implementations
the Printer object might be a central clearing-house for
all Job object creation requests, but the Job object itself might
created in some environment that is remote from the Printer object
In this case, the Job object's URI may have no physical-

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relationship at all to the Printer object's URI. Again, the
that Job objects have URIs allows for flexibility and scalability
however, many existing printing systems have local models
interface constraints that force print jobs to be identified
only a 32-bit positive integer rather than an independent URI.
numeric Job ID is only unique within the context of the
object to which the create request was originally submitted
Therefore, in order to allow both types of client access to IPP
objects (either by Job URI or by numeric Job ID), when the
object successfully processes a create request and creates a new
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
context of the Printer object to which the create request
originally submitted. This requirement to support both Job URIs
Job IDs allows all types of clients to access Printer objects and
objects no matter the local constraints imposed on the
implementation

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

To summarize

- Each Printer object is identified with one or more URIs.
Printer's "printer-uri-supported" attribute contains the URI(s).
- The Printer object's "uri-security-supported"
identifies the communication channel security protocols that
or may not have been configured for the various Printer
URIs (e.g., 'tls' or 'none').
- The Printer object's "uri-authentication-supported"
identifies the authentication mechanisms that may or may
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
the Job ID. The Job ID is only unique within the context of
Printer object which created the Job object

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- Each Job object has a "job-printer-uri" attribute which
the URI of the Printer object that was used to create the
object. This attribute is used to determine the Printer
that created a Job object when given only the URI for the
object. This linkage is necessary to determine the languages
charsets, and operations which are supported on that Job (
basis for such support comes from the creating Printer object).
- Each Printer object has a name (which is not
unique). The administrator chooses and sets this name
some mechanism outside the scope of this IPP/1.1 document.
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
generates a name for the Job object. The Job object's "job-name
attribute contains the name

3. IPP

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

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

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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
document to an existing multi-document Job object created using
Create-Job operation

3.1 Common

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

3.1.1 Required

Every operation request contains the following REQUIRED parameters

- a "version-number",
- an "operation-id",
- a "request-id",
- 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

- the attributes that are REQUIRED for that type of response

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

3.1.2 Operation IDs and Request

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
which operation is being requested by supplying the
"operation-id" value

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

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

3.1.3

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

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

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

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

The attributes within a group MUST be unique; if an attribute
the same name occurs more than once, the group is mal-formed
Clients MUST NOT submit such malformed requests and Printers MUST
return such malformed responses. If such a malformed request

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submitted to a Printer, the Printer MUST either (1) reject
request with the 'client-error-bad-request' status code (see
13.1.4.1) or (2) process the request normally after selecting
one of the attribute instances, depending on implementation.
attribute is selected when there are duplicate attributes depends
implementation. The IPP Printer MUST NOT use the values from
than one such duplicate attribute instance

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

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

Some operations are REQUIRED for IPP objects to support; the
are OPTIONAL (see section 5.2.2). Therefore, before using
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
Job operations are actually supported. The client SHOULD NOT use
OPTIONAL operation that is not supported. When an IPP
receives a request to perform an operation it does not support,
returns the 'server-error-operation-not-supported' status code (
section 13.1.5.2). An IPP object is non-conformant if it does
support a REQUIRED operation

3.1.4