INTERNET-DRAFT
draft-ietf-ipp-model-06.txt
R. deBry
IBM Corporation
T. Hastings
Xerox Corporation
R. Herriot
Sun Microsystems
S. Isaacson
Novell, Inc.
P. Powell
San Diego State University
October 14, 1997
Internet Printing Protocol/1.0: Model and Semantics
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
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To learn the current status of any Internet-Draft, please check the
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munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).
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 technology. The protocol 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 1.0 is focused only
on end user functionality.
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The full set of IPP documents includes:
Requirements for an Internet Printing Protocol [IPP-REQ]
Internet Printing Protocol/1.0: Model and Semantics
Internet Printing Protocol/1.0: Protocol Specification [IPP-PRO]
Rationale for the Structure and Model and Protocol for the Internet
Printing Protocol [IPP-RAT]
The requirements document, "Requirements for an Internet Printing
Protocol", 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. The requirements document calls
out a subset of end user requirements that MUST be satisfied in the
first version of IPP. Operator and administrator requirements are out
of scope for v1.0. This document, "Internet Printing Protocol/1.0:
Model and Semantics", describes a simplified model with abstract
objects, their attributes, and their operations. The model introduces
a Printer object and a Job object. The Job object supports multiple
documents per job. The model document also addresses how security,
internationalization, and directory issues are addressed. The protocol
specification, " Internet Printing Protocol/1.0: Protocol
Specification", is a formal mapping of the abstract operations and
attributes defined in the model document onto HTTP/1.1. The protocol
specification defines the encoding rules for a new Internet media type
called "application/ipp".
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Table of Contents
1. Simplified Printing Model .......................................8
2. IPP Objects ....................................................10
2.1 Printer Object................................................10
2.2 Job Object....................................................13
2.3 Object Relationships..........................................14
2.4 Object Identity...............................................14
3. IPP Operations .................................................15
3.1 General Semantics.............................................16
3.1.1 Operation Characteristics................................16
3.1.2 Operation Targets........................................18
3.1.3 Character Set and Natural Language Operation Attributes..19
3.1.3.1 Request Operation Attributes ..........................19
3.1.3.2 Response Operation Attributes .........................20
3.1.4 Operation Status Codes and Messages......................21
3.1.5 Security Concerns for IPP Operations.....................22
3.1.5.1 Authenticated Requester Identity ......................22
3.1.5.2 Restricted Queries ....................................23
3.1.6 Versions.................................................23
3.1.7 Job Creation Operations..................................24
3.2 Printer Operations............................................26
3.2.1 Print-Job Operation......................................26
3.2.1.1 Print-Job Request .....................................26
3.2.1.2 Print-Job Response ....................................28
3.2.2 Print-URI Operation......................................30
3.2.3 Validate-Job Operation...................................31
3.2.4 Create-Job Operation.....................................31
3.2.5 Get-Attributes Operation.................................31
3.2.5.1 Get-Attributes Request ................................32
3.2.5.2 Get-Attributes Response ...............................33
3.2.6 Get-Jobs Operation.......................................34
3.2.6.1 Get-Jobs Request ......................................34
3.2.6.2 Get-Jobs Response .....................................35
3.3 Job Operations................................................36
3.3.1 Send-Document Operation..................................37
3.3.1.1 Send-Document Request .................................37
3.3.1.2 Send-Document Response ................................39
3.3.2 Send-URI Operation.......................................39
3.3.3 Cancel Job Operation.....................................39
3.3.3.1 Cancel-Job Request ....................................40
3.3.3.2 Cancel-Job Response ...................................40
3.3.4 Get-Attributes Operation.................................41
3.3.4.1 Get-Attributes Request ................................41
3.3.4.2 Get-Attributes Response ...............................41
4. Object Attributes ..............................................42
4.1 Attribute Syntaxes............................................42
4.1.1 'text'...................................................43
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4.1.2 'name'...................................................44
4.1.3 'keyword'................................................44
4.1.4 'enum'...................................................45
4.1.5 'uri'....................................................45
4.1.6 'uriScheme'..............................................45
4.1.7 'charSet'................................................46
4.1.8 'naturalLanguage'........................................46
4.1.9 'mimeType'...............................................47
4.1.10 'octetString'............................................48
4.1.11 'boolean'................................................48
4.1.12 'integer'................................................48
4.1.13 'rangeOfInteger'.........................................48
4.1.14 'dateTime'...............................................48
4.1.15 'resolution'.............................................48
4.1.16 '1setOf X'..............................................49
4.2 Job Template Attributes.......................................49
4.2.1 job-sheets (type4 keyword, name).........................53
4.2.2 job-priority (integer(1:100))............................54
4.2.3 job-hold-until (type4 keyword, name).....................55
4.2.4 multiple-document-handling (type2 keyword)...............56
4.2.5 media (type4 keyword, name)..............................57
4.2.6 number-up (integer)......................................57
4.2.7 sides (type2 keyword)....................................58
4.2.8 printer-resolution (resolution)..........................59
4.2.9 print-quality (type2 enum)...............................59
4.2.10 finishings (1setOf type2 enum)...........................59
4.2.11 copies (integer(1:2**31 - 1))............................60
4.2.12 page-ranges (1setOf rangeOfInteger)......................60
4.2.13 orientation (type2 enum).................................61
4.2.14 document-format (mimeType)...............................61
4.2.15 compression (type3 keyword)..............................62
4.2.16 job-k-octets (integer(0:2**31 - 1))......................62
4.2.17 job-impressions (integer(0:2**31 - 1))...................62
4.2.18 job-media-sheets (integer(0:2**31 - 1))..................63
4.3 Job Description Attributes....................................63
4.3.1 job-uri (uri)............................................64
4.3.2 job-id (integer(1:MAX))..................................65
4.3.3 job-more-info (uri)......................................65
4.3.4 job-name (name)..........................................65
4.3.5 job-originating-user (octetString).......................65
4.3.6 job-state (type1 enum)...................................66
4.3.7 job-state-reasons (1setOf type2 keyword)................68
4.3.8 job-state-message (text).................................70
4.3.9 number-of-documents (integer(0:2**31 - 1))...............70
4.3.10 output-device-assigned (name)............................71
4.3.11 time-of-creation (integer)...............................71
4.3.12 time-at-processing (integer).............................71
4.3.13 time-at-completed (integer)..............................71
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4.3.14 number-of-intervening-jobs (integer(0:2**31 - 1))........71
4.3.15 job-message-from-operator (text).........................71
4.3.16 job-k-octets-processed (integer(0:2**31 - 1))............72
4.3.17 job-impressions-completed (integer(0:2**31 - 1))........72
4.3.18 job-media-sheets-completed (integer(0:2**31 - 1))........72
4.3.19 attributes-charset (charSet).............................72
4.3.20 attributes-natural-language (naturalLanguage)............73
4.4 Printer Description Attributes................................73
4.4.1 printer-uri (uri)........................................75
4.4.2 printer-name (name)......................................75
4.4.3 printer-location (text)..................................75
4.4.4 printer-info (text)......................................75
4.4.5 printer-more-info (uri)..................................75
4.4.6 printer-driver-installer (uri)...........................76
4.4.7 printer-make-and-model (text)............................76
4.4.8 printer-more-info-manufacturer (uri).....................76
4.4.9 printer-state (type1 enum)...............................76
4.4.10 printer-state-reasons (1setOf type2 keyword).............77
4.4.11 printer-state-message (text).............................80
4.4.12 operations-supported (1setOf operation)..................80
4.4.13 printer-charset (charSet)................................81
4.4.14 charsets-supported (1setOf charSet)......................81
4.4.15 printer-natural-language (naturalLanguage)...............81
4.4.16 natural-languages-supported (1setOf naturalLanguage).....81
4.4.17 printer-is-accepting-jobs (boolean)......................82
4.4.18 queued-job-count (integer(0:2**31 - 1))..................82
4.4.19 printer-message-from-operator (text).....................82
4.4.20 color-supported (boolean)................................82
4.4.21 reference-uri-schemes-supported (1setOf uriScheme).......83
4.4.22 pdl-override (type2 keyword).............................83
4.4.23 security-mechanisms-supported (1setOf keyword)...........83
4.4.24 printer-up-time (integer(1:MAX)).........................84
4.4.25 printer-current-time (dateTime)..........................84
4.4.26 multiple-operation-time-out (integer)....................84
5. Conformance ....................................................84
5.1 Client Conformance Requirements...............................85
5.2 Printer Object Conformance Requirements.......................85
5.2.1 Objects..................................................86
5.2.2 Operations...............................................86
5.2.3 Attributes...............................................86
5.2.4 Printer extensions.......................................87
5.2.5 Attribute Syntaxes.......................................87
5.3 Security Conformance Requirements.............................87
6. IANA Considerations (registered and private extensions) ........87
6.1 Typed Extensions..............................................88
6.2 Registration of MIME types/sub-types for document-formats.....89
6.3 Attribute Extensibility.......................................89
6.4 Attribute Syntax Extensibility................................89
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7. Internationalization Considerations ............................89
8. Security Considerations ........................................91
8.1 Client and Printer in the Same Security Domain................92
8.2 Client and Printer in Different Security Domains..............92
8.3 Print by Reference............................................93
8.3.1 Unprotected Documents....................................93
8.3.2 Protected Documents......................................93
8.4 Common Security Scenarios.....................................93
8.4.1 No Security..............................................93
8.4.2 Message Protection During Transmission...................94
8.4.3 Client Authentication and Authorization..................94
8.4.4 Mutual Authentication, Authorization and Message Protection
94
8.5 Recommended Security Mechanisms...............................94
9. References .....................................................95
10.Copyright Notice ...............................................99
11.Author's Address ...............................................99
12.APPENDIX A: Terminology .......................................102
12.1 Conformance Terminology......................................102
12.1.1 MUST....................................................102
12.1.2 MUST NOT................................................102
12.1.3 SHOULD..................................................102
12.1.4 SHOULD NOT..............................................102
12.1.5 MAY.....................................................102
12.1.6 NEED NOT................................................103
12.2 Model Terminology............................................103
12.2.1 Keyword.................................................103
12.2.2 Attributes..............................................103
12.2.2.1 Attribute Name .......................................103
12.2.2.2 Attribute Group Name .................................104
12.2.2.3 Attribute Value ......................................104
12.2.2.4 Attribute Syntax .....................................104
12.2.3 Supports................................................104
12.2.4 print-stream page.......................................106
12.2.5 imposed page............................................106
13.APPENDIX B: Status Codes .....................................106
13.1 Status Codes.................................................107
13.1.1 Informational...........................................107
13.1.2 Successful Status Codes.................................107
13.1.2.1 successful-ok (0x0000) ...............................107
13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001)
108
13.1.3 Redirection Status Codes................................108
13.1.4 Client Error Status Codes...............................108
13.1.4.1 client-error-bad-request (0x0400) ....................108
13.1.4.2 client-error-forbidden (0x0401) ......................108
13.1.4.3 client-error-not-authenticated (0x0402) ..............108
13.1.4.4 client-error-not-authorized (0x0403) .................109
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13.1.4.5 client-error-not-possible (0x0404) ...................109
13.1.4.6 client-error-timeout (0x0405) ........................109
13.1.4.7 client-error-not-found (0x0406) ......................109
13.1.4.8 client-error-gone (0x0407) ...........................110
13.1.4.9 client-error-request-entity-too-large (0x0408) .......110
13.1.4.10 client-error-request-URI-too-long (0x0409) ...........110
13.1.4.11 client-error-unsupported-document-format (0x040A) ....110
13.1.4.12 client-error-attribute-not-supported (0x040B) ........111
13.1.4.13 client-error-uri-scheme-not-supported (0x040C) .......111
13.1.4.14 client-error-charset-not-supported (0x040D) ..........111
13.1.4.15 client-error-natural-language-not-supported (0x040E) .111
13.1.5 Server Error Status Codes...............................111
13.1.5.1 server-error-internal- error (0x0500) ................112
13.1.5.2 server-error-operation-not-supported (0x0501) ........112
13.1.5.3 server-error-service-unavailable (0x0502) ............112
13.1.5.4 server-error-version-not-supported (0x0503) ..........112
13.1.5.5 server-error-device-error (0x0504) ...................112
13.1.5.6 server-error-temporary-error (0x0505) ................113
13.2 Status Codes for IPP Operations..............................114
14.APPENDIX C: "media" keyword values ...........................114
15.APPENDIX D: Processing IPP Attributes .........................119
15.1 Fidelity.....................................................119
15.2 Page Description Language (PDL) Override.....................121
15.3 Suggested Operation Processing Algorithm.....................122
15.4 Using Job Template Attributes During Document Processing.....126
16.APPENDIX E: Generic Directory Schema ..........................127
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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 does not
include features, interfaces, and relationships that are beyond the
scope of IPP/1.0. IPP incorporates many of the relevant ideas and
lessons learned from other specification and development efforts
[HTPP] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP].
The IPP 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).
The terminology used in the remainder of this document is defined in
(section 12). In the remainder of this document, terms such as
"attributes", "keywords", and "supports" have special meaning and are
defined in the model terminology section. Capitalized terms such as
MANDATORY, SHALL, and OPTIONAL have special meaning relating to
conformance. These terms are defined in the section on conformance
terminology, most of which is taken from RFC 2119 [RFC2119].
It is important, however, to understand that in real system
implementations (which lie underneath the abstracted IPP model), there
are other components of a print service which are not explicitly
defined in the IPP model. The following figure illustrates where IPP
fits with respect to these other components.
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+--------------+
| 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 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. IPP Printers 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. 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. (see
section 16). The more dynamic information is directly associated with
the IPP Printer itself. This information includes state, currently
loaded and ready media, number of jobs at the Printer, errors,
warnings, and so forth.
IPP Clients implement the IPP protocol on the client side, and give
end users (or programs) the ability to query an IPP Printer and submit
and manage print jobs. An IPP server is just that part of the IPP
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Printer that implements the server-side protocol. The rest of the IPP
Printer implements the application semantics of the print service
itself. The IPP Printer may be embedded in an output device or may be
implemented on a host on the network that communicates with the 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.
End users may also cancel print job by using the Job object's Cancel-
Job operation. The end user is able to register to receive certain
events that are then routed using the specified notification
service(s).
2. IPP Objects
The IPP 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 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, 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 object type Printer is defined as a set of attributes
that each Printer object potentially supports. In the same manner,
the object type Job 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:
- "MANDATORY": each object SHALL support the attribute.
- "OPTIONAL": each object OPTIONALLY supports the attribute.
There is no such similar labeling of attribute values. However, if an
implementation supports an attribute, it MUST support at least one of
the possible values for that attribute.
2.1 Printer Object
A major component of the IPP model is the Printer object (also called
the IPP Printer). A Printer object implements the IPP protocol.
Using the protocol, end users may query the attributes of the Printer
and submit Jobs to the Printer. The actual implementation components
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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 grouped into two groups:
- "job-template" attributes: These attributes the describe 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 might or might not be capable
of spooling jobs
3b) The associated output devices might or might 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 configuration 3.
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Legend:
##### indicates a Printer object which is
either embedded in an output device or is
hosted in a server. The implementation
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 |
| |
+---------------+
A Printer object is identified with a Uniform Resource Identifier
(URI) [RFC1630]. Often, the URI is a Uniform Resource Locator (URL)
[RFC1738] [RFC1808]..
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Note: The IPP protocol specification [IPP-PRO] defines a mapping of
IPP onto HTTP/1.1. Therefore, all conforming Printer objects SHALL
support HTTP schemed URIs to identify themselves. For example, a
Printer object's URI could be "http://www.some-domain.org/printer-
one". A Printer object's URI could not be "ftp://ftp.some-
domain.org/printer-one".
IPP does not specify how the URI is obtained, but it is RECOMMENDED
that a Printer object is registered in a directory service which end
users and programs can interrogate. Section 16 defines a generic
schema for Printer object entries in the directory service.
2.2 Job Object
A Job object is used to model a print job. A Job can contain one or
more 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. 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 are optionally
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 does not
supply values for these attributes, they are set by the Printer
object. (See section 4.3)
A Job object contains at least one document, but may contain multiple
documents. A document consists of either:
- a stream of data in a format supported by the Printer object, or
- a URI reference to a stream of data in a format supported by the
Printer
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.
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2.3 Object Relationships
IPP objects have relationships that MUST be maintained persistently
along with the persistent storage of the object attributes. A Printer
object may represent one or more output devices. A Printer object may
represent a logical device which "processes" jobs but never actually
uses a physical output device to put marks on paper (for example a Web
page publisher or an interface 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 new
Job object would be created which would be almost identical to the
existing Job object, however it would have a new (different) Job
object identifier. A Job object contains one or more documents. If
the contained document is a stream of printer-ready data, that stream
can be contained in only one document. However, there can be copies
of the stream in other documents in the same or different Job objects.
If the contained document is a reference to a stream of printer-ready
data, other documents (in the same or different Job object(s)) may
reference the same stream.
2.4 Object Identity
All Printer and Job objects have an identifier so that they can be
persistently and unambiguously referenced. The IPP model requires
that these identifiers be URIs. Often, the URI is a URL [RFC1738]
[RFC1808].
Allowing Job objects to have URIs allows for flexibility and
scalability. 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. In
other implementations, the Printer object might be a central clearing-
house for validating all Job object creation requests, and 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
relationship at all to the Printer object's URI.
However, many existing printing systems have local models or interface
constraints that force Job objects to be identified using only a 32-
bit positive integer rather than a URI. This numeric Job ID is only
unique within the context of the Printer object to which the create
request was originally submitted. In order to allow both types of
client access to Jobs (either Job URI or numeric Job ID), when the
Printer object successfully processes a create request and creates a
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new Job, the Printer object SHALL generate both a Job URI and a Job ID
for the new Job object. This requirement allows all clients to access
Printer objects and Job objects no matter the local constraints
imposed on the client implementation.
In addition to a unique identifier, Printer objects and Job objects
may have names. 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 IPP. 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, and it is not constrained to
be unique.
To summarize:
- Each Printer object is uniquely identified with a URI. The
Printer's "printer-uri" attribute contains the URI.
- Each Job object is uniquely identified with a URI. The Job's
"job-uri" attribute contains the URI.
- Each Job object is also uniquely identified with a combination of
the URI of the Printer object to which the create request was
originally submitted along with a Job ID (a 32-bit, positive
number) that is unique within the context of that Printer object.
The Printer object's "printer-uri" contains the Printer URI. The
Job object's "job-id" attribute contains the numeric Job ID.
- 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 IPP itself. 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 have associated operations. An operation consists of a
request and a response. When a client communicates with an IPP
object, it issues an operation request to the URI for that object.
Operations have attributes that supply information about the operation
itself. These attributes are called operation attributes (as compared
to object attributes such as Printer attributes or Job attributes).
Each request carries along with it any operation attributes and/or
document data required by the object to perform the operation. Each
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request requires a response from the object. Each response indicates
success or failure of the operation with a status code. The response
contains any operation attributes, object attributes, and/or status
messages generated by the execution of the operation request.
This section describes the semantics of the IPP operations, both
requests and responses, in terms of the attributes and other data
associated with each operation.
Note: The IPP protocol specification [IPP-PRO] describes a mapping and
encoding of IPP operations onto HTTP/1.1 POST commands. Other
mappings for IPP operations to additional transport mechanisms are
possible.
The 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-Attributes (section 3.2.5)
Get-Jobs (section 3.2.6)
The Job operations are:
Send-Document (section 3.3.1)
Send-URI (section 3.3.2)
Cancel-Job (section 3.3.3)
Get-Attributes (section 3.3.4)
The Send-Document and Send-URI Job operations are used to add a new
document to an existing multi-document Job object created with the
Create-Job operation.
3.1 General Semantics
3.1.1 Operation Characteristics
Each IPP operation is defined as both a request and a response. Both
requests and responses are composed of groups of attributes and/or
document data. Attributes are grouped into the following groups:
- Operation Attributes: These are attributes that are only passed
in the operation itself, and usually do not persist beyond the
life of the operation. Operation attributes may also affect
other attributes or groups of attributes since values in the
operation attributes usually affect the behavior of the object
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that processes the operation. All IPP objects that accept IPP
operation request MUST support all operation attributes. Some
operation attributes are OPTIONAL for the client to supply, but
the IPP object MUST support the attribute by being prepare to
handle the client supplied operation attribute by realizing the
corresponding feature or function.
- Job Template Attributes: These attributes affect the processing
of a job. They are OPTIONALLY supplied by a client in a create
request, and the receiving object MUST be prepared to received
all supported attributes. The Job object can later be queried to
find out what was originally requested in the create request.
The Printer object can be queried to find out what type of job
processing capabilities are supported and/or what the default job
processing behaviors are.
- Job Object Attributes: These attributes are returned in response
to 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
an optional set of Job Template attributes. If any of these are
unsupported by the Printer object, the Printer object returns
them in the response. Section 15 gives 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.
Later in this section, each operation is formally defined by
identifying the allowed and expected groups of attributes for 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.
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 operations responses that include document data.
Since some operations are MANDATORY and some are OPTIONAL, a client
SHOULD first use the MANDATORY Get-Attributes operation to query the
Printer's "operations-supported" attribute before using any
unsupported operation. A client SHOULD NOT attempt to use an
unsupported operation. When a Printer object receives a request to
perform an operation it does not support, it returns the error code
'server-error-operation-not-supported' (see section 13.1.5.2).
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3.1.2 Operation Targets
All IPP operations are directed at IPP objects. For Printer
operations, the operation is always directed at a Printer object using
its URI (the "printer-uri" attribute).
For Job operations, the operation is directed at either:
- the Job object itself using the Job object's URI ("job-uri")
assigned by the Printer object, or
- the Printer object to which the job was originally submitted
using the URI of the Printer ("printer-uri") in combination with
and the 32-bit numeric Job ID ("job-id") assigned by the Printer
object.
If the operation is directed at the Job object directly using the Job
object's URI, the client SHOULD NOT include the redundant "job-id"
operation attribute.
Note: In the mapping of IPP over HTTP/1.1, the object's URI is
actually encoded as the "request-URI" field of the HTTP POST
operation. In the case of Printer operations directed at a Printer
object, the Printer object's "printer-uri" attribute is mapped to the
"request-URI" attribute in the HTTP header. In the case of Job
operations directed at the Job object, the Job object's "job-uri"
attribute is mapped to the "request-URI" attribute in the HTTP header.
In the case of Job operations directed at the Printer object that
created the Job, the Printer object's "printer-uri" attribute is sent
in the HTTP header, and the "job-id" attribute is sent as an
operational attribute in the request body. In other mappings of IPP
operations onto some other transport mechanism, the target URI is
encoded using some other transport specific addressing mechanism.
The following rules apply to the use of port numbers in URIs that
identify IPP objects:
1. If the protocol scheme for the URI allows the port number to be
explicitly included in the URI string, and an explicit port
number is specified in the published URI, then that port number
MUST be used by the client to contact the IPP server.
2. If the protocol scheme for the URI does not allow an explicit
port number specification, then the default port number for the
protocol should be used.
3. Consult the appropriate IPP protocol mapping document to
determine alternate port numbers for the protocol specified in
the server URI.
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3.1.3 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 MANDATORY
attributes for every IPP operation request and response. These
attributes are "attributes-charset" and "attributes-natural-language".
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.
3.1.3.1 Request Operation Attributes
The client SHALL supply and the Printer object SHALL support the
following MANDATORY operation attributes in every IPP 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 and that the Printer
object SHALL return in this operation response. See Sections
4.1.1 and 4.1.2 for the specification of the 'text' and 'name'
attribute syntaxes.
The Printer object SHALL support the 'utf-8' charset [RFC2044]
and MAY support additional charsets provided that they are
registered with IANA [IANA-CS]. If the Printer object does not
support the supplied charset value, the Printer object SHALL
reject the request and return status code 'client-error-charset-
not-supported'. The Printer object SHALL indicate the charset(s)
supported as the values of the "charsets-supported" Printer
attribute (see Section 4.4.14), so that the client MAY query
which charset(s) are supported.
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. A Printer SHOULD do its best to respond in the
same natural language.
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There are no MANDATORY natural languages required for the Printer
object to support. However, the Printer's "natural-language-
supported" attribute SHALL list the natural languages supported,
so that the client MAY query which natural language(s) are
supported. For any of the attributes for which the Printer
generates messages, i.e., for the "job-state-message", "printer-
state-message" attributes ", and Status Messages (see Section
3.1.4) in operation responses, the Printer object SHALL be able
to generate messages in any of its supported natural languages.
If the client requests a natural language that is not supported,
the Printer object SHALL return these generated messages in the
Printer's configured natural language as specified by the
Printer's "printer-natural-language " attribute" (see Section
4.4.15).
For other Printer 'text' and 'name' attributes supplied 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), the Printer object
is only required to support the configured natural language of
the Printer identified by the Printer's "printer-natural-language
" attribute, though support of additional natural languages for
these attributes is permitted
If the Printer object does not support the natural language value
supplied by the client, the Printer object SHALL either (1)
reject the request and return status code ' client-error-natural-
language-not-supported' or (2) accept the natural language rather
than returning an error, depending on implementation. In the
latter case, the Printer object SHALL use the method for
representing exception natural languages in attribute values as
described for the 'text' attribute syntax in Section 4.1.1 for
any such 'text' or 'name' attributes that the Printer (1) accepts
from or (2) returns to a client.
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.
3.1.3.2 Response Operation Attributes
The Printer object SHALL supply and the client SHALL support the
following MANDATORY operation attributes in every IPP operation
response:
"attributescharset" (charSet):
This operation attribute identifies the charset used by any
'text' and 'name' attributes that the Printer object is returning
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in this response. The value in this response SHALL be the same
value as the "attributes-charset" operation attribute supplied by
the client in the request. See "attributes-charset" described in
Section 3.1.3.1 above.
If the Printer object supports more than just the 'utf-8'
charset, the Printer object SHALL 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.
"attributes-natural-language" (naturalLanguage):
This is a MANDATORY Job Template attribute for the Printer object
to return. This attribute specifies the natural language used by
'text' and 'name' attributes with empty tags in this response and
SHALL be the same value as supplied by the client in the request,
whether the Printer object supports that value or not. Any
'text' or 'name' values in this response that have a different
natural language SHALL have a fully specified natural language
tag pre-pended to each such attribute value.
In a subsequent query request (Get-Attributes or Get-Jobs), the
Printer object NEED NOT convert any 'text' or 'name' attribute
values to the natural language of the requester when it is
different from that specified (and subsequently stored) in the
original create request.. In such cases, the Printer object
SHALL return an explicit natural language indicator for each such
attribute value. See the 'text' attribute syntax description in
Section 4.1.1.
3.1.4 Operation Status Codes and Messages
Every operation response returns a MANDATORY status code and an
OPTIONAL status message. A status code provides information on the
processing of a request. A status message provides a short textual
description of the status of the operation. The status code is
intended for use by automata and the status message is intended for
the human user. If a response does include a status message, an IPP
client is not required to examine or display the status message,
however it SHOULD do so in some implementation specific manner.
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Section 13 describes the status codes and suggests a corresponding
status message for each status code. In some cases, if the status
code indicates an error, there may be additional attributes in the
response that are not returned in the successful case. One such
example is the set of unsupported attributes in the Print-Job response
(see section 3.2.1.2).
The status code is a numeric value that has semantic meaning. The
status code is similar to a "type2 enum" (see section 4.1 on
"Attribute Syntaxes") except that values can range only from 0x0000 to
0xFFFF.
A client implementation of IPP could convert status code values into
any localized string that has semantic meaning to the end user. The
Printer object SHALL be able to generate this message in any of the
natural languages identified by the Printer's "natural-language-
supported" attribute (see the "attributes-natural-language" operation
attribute specified in Section 3.1.3.1). If the charset requested by
the client in the "attributes-charset" operation attribute is not
supported by the Printer object, the Printer object SHALL represent
the status message, if returned, in the charset specified by the
Printer's "printer-charset" attribute (which the client MAY not be
able to interpret).
3.1.5 Security Concerns for IPP Operations
3.1.5.1 Authenticated Requester Identity
IPP is layered on top of security services that supply the requester's
identity. It is assumed that the identity supplied by the
authentication service is the most authenticated identity required by
a given site's configuration and current policy. It is also assumed
that the layering allows for a single IPP implementation to be run
over a consistent interface that supplies the authenticated identity.
The authentication interface should allow for various modular and
extensible authentication service implementations without requiring
changes to the IPP implementation.
Once the authenticated identity of the requester has been supplied to
the IPP implementation, the implementation uses that identity to
enforce any authorization policy(ies) that might be in place. When a
Job is created, the identity of the requester from the create request
is persistently stored in the Job's "job-originating-user" attribute.
This attribute can be used to match the requester's identity of
subsequent operations on that Job in order to enforce the local
authorization policy(ies), if any. For example, a one site's policy
might be that only the job owner is allowed to cancel a job. There
are operation status codes that allow an implementation to return
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information back to the operation requester about what has been
forbidden, not allowed, or not authorized. The details of and
mechanisms to set up authorization policy(ies) are not part of IPP,
and must be established via some mechanism outside the scope of IPP.
3.1.5.2 Restricted Queries
In many of these IPP operations, a client supplies a list of
attributes to be returned in the response. A Printer may be
configured, for security reasons, not to return all attributes that a
client requests. It may even return none of the requested attributes.
In such cases, the status returned is the same as if the Printer had
returned all requested attributes. The client cannot tell by such a
response whether the requested attribute was present or absent on the
Printer or Job.
3.1.6 Versions
Each operation request carries with it a version number. Each 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 (the requester) to identify which
version of IPP it is interested in using. If the Printer does not
support that version, the Printer responds with a status code of
'server-error-version-not-supported'.
There is no version negotiation per se. However, if after receiving a
version not supported status code from the Printer, there is nothing
that prevents a client from trying again with a different version
number. For example, a client might be configured to support IPP
version 3.0, 2.5, 2.0 and 1.0 (hypothetically speaking). A client
might first try to speak version 3.0. If after receiving a version not
supported, it might successively try version 2.5, then 2.0, and then
1.0. All implementations MUST support version 1.0.
There is only one version number that covers both IPP Model and the
IPP Protocol changes. Thus the version number MUST change when
introducing a new version of the Model document or a new version of
the Protocol document.
Changes to the major version number indicate structural or syntactic
changes that make it impossible for older version IPP processors to
correctly parse and interpret the new or changed attributes,
operations and responses. If the major version number changes, the
minor version numbers is set to zero. One example that would have
required a change to the major version number would have been adding
the "ipp-attribute-fidelity" attribute if it had not been part of
version 1.0. Items that might affect the changing of the major version
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number include any changes to the protocol specification itself such
as:
- reordering of ordered attributes or attribute sets
- changes to the syntax of existing attributes
- changing OPTIONAL to MANDATORY and vice versa
Changes to the minor version number indicate the addition of new
features, attributes and attribute values that may not be understood
by all IPP processors, 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
protocol specification itself, such as:
- grouping all extensions not included in a previous version into a
new version
- formally adding in new attribute values
- changing any of the type1 attributes
3.1.7 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 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 "pulls" the
document data uses the Print-URI operation. In this case, the
client includes 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 of Send-Document 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 document.
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Throughout this model specification, 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 MANDATORY operation
(all implementations MUST support it) whereas Create-Job is an
OPTIONAL operation, hence some implementations might not support it.
Section 15 describes the rules and issues surrounding the processing
and either the acceptance or rejection of a create request.
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' or
'pending-held' state. Later, the Printer object begins processing the
job. At this point in time, 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 using the rules supplied
in section 15 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 SHOULD NOT perform the validation
checks reserved for job processing time such as:
1. Validate the document data
2. Validate 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 yet be done 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,
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- 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 processing time, since the Printer 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 in unable to
inform the end user of the error with an operational status code. In
this case, the Printer, depending on the error, can set the "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.
3.2 Printer Operations
All Printer operations are directed at Printer objects. A client MUST
always supply the "printer-uri" attribute in order to identify the
correct target of the operation. In HTTP/1.1 mapping of IPP, this
attribute is not supplied in the body of the operation as other
operation attributes are. It is supplied in the "request-URI" field
in the HTTP header.
3.2.1 Print-Job Operation
When an end user desires to submit a print job with only one document
and the client supplies the document data (rather than just a
reference to the data), the client uses a Print-Job operation.
3.2.1.1 Print-Job Request
The following groups of attributes are supplied as part of the Print-
Job Request:
Group1: Operation Attributes
Target:
The "printer-uri" target for this operation as described in
section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"job-name" (name):
This attribute is OPTIONALLY supplied by the client, and it
contains the client supplied Job name. If this attribute is
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supplied, its value it used for the "job-name" attribute of the
newly created Job object. 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 4.3.4).
"document-name" (name):
This attribute is OPTIONALLY supplied by the client, and 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 (banner page, page adornments, etc.), used by
accounting or resource tracking management tools, or even stored
along with the document as a document level attribute. IPP/1.0
does not support the concept of document level attributes,
however, a vendor specific extension to IPP/1.0 might support the
document level attributes. In this case, the "document-name"
attribute could be persistently stored along with the document
and queried using a Get-Attributes operation on the Job object
that includes a request for document level attributes or some
other private extension mechanism.
"ipp-attribute-fidelity" (boolean):
This attribute is OPTIONALLY supplied by the client. If not
supplied, the Printer object assumes the value is 'false'. The
value 'true' indicates that total fidelity to client supplied
attributes and values is required. The value 'false' indicates
that a reasonable attempt to print the Job is acceptable. 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" attribute.
"document-charset" (charSet):
This attribute is OPTIONALLY supplied by the client. A Printer
object SHALL support this attribute if it supports a document-
format that requires a character set to be identified in order to
unambiguously interpret the document, such as 'text/plain'.
There are no particular values required for the Printer object to
support. This attribute specifies the charset of the document
for those document-formats that require a specification of the
charset in order to image the document unambiguously. If the
value of the "document-format" attribute contains a charset
parameter (see 'mimeType' attribute syntax in Section 4.1.9), the
client SHALL also supply the "document-charset" attribute and its
value SHALL be the same.
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"document-natural-language" (naturalLanguage):
This attribute is OPTIONALLY supplied by the client. There are
no particular values are required for the Printer object to
support. 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.
Group2: Job Template Attributes
The client OPTIONALLY supplies a set of Job Template attributes
as defined in section 4.2. See section 15 for a full description
of Job Template attributes.
Group 3: Document Content
The client MUST supply the document data to be processed.
Note: The simplest Print-Job Request consists of just the Document
Content and nothing else. In this 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,
- assumes that the document data is in a supported format, and
- uses its corresponding default value attributes for missing Job
Template attributes and embedded instructions in the document
data.
3.2.1.2 Print-Job Response
The Printer SHALL return to the client the following sets of
attributes as part of the Print-Job Response:
Group 1: Operation Attributes
Status Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
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Group 2: Job Object Attributes
"job-uri" (uri):
The Printer object MUST return the Job object's MANDATORY "job-
uri" attribute.
"job-id":
The Printer object MUST return the Job object's MANDATORY "job-
id" attribute.
"job-state":
The Printer object MUST return the Job object's MANDATORY "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":
The Printer object OPTIONALLY returns the Job object's OPTIONAL
"job-state-reasons" 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-reasons" attribute is not supported
and will not be returned in a subsequent Job object query.
"job-state-message":
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":
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.
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Group 3: Unsupported Attributes
This is an OPTIONAL set of attributes. It is a set of Job
Template attributes supplied by the client (in the request) that
are not supported by the Printer object. When the Printer object
rejects the request because of more than one unsupported
attribute (see section 15), it SHOULD return all of the
unsupported attributes. Some implementations may choose to only
return the first unsupported attribute that is encountered during
the processing of the attributes, but that may lead to additional
requests with only one "fixed" attribute from the set of problem
attributes. In the case where the Printer object accepts the
request and creates a Job object, the Printer MUST return the set
of unsupported attributes where substitutions were made or the
attribute was completely ignored.
Unsupported attributes fall into two categories:
1. The Printer object does not support the named attribute (no
matter what the value), or
2. The Printer object does supports the attribute, but not the
particular value supplied by the client (i.e., the Printer does
not have that value in the corresponding supported values
attribute).
In the case of an unsupported attribute name, the Printer object
returns the client supplied attribute with a substituted special
value of 'unsupported' indicating no support for the attribute
itself. In the case of a supported attribute with an unsupported
value, the Printer object simply returns the client-supplied
attribute. This indicates support for the attribute, but no
support for that particular value.
Note: The simplest response consists of the just the MANDATORY Job
Attributes and a status code of "successful-ok".
3.2.2 Print-URI Operation
This 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 rather than
including the document data itself. It is up to the IPP server to
interpret the URI and subsequently "pull" the document from the source
referenced by the URI string. At job submission time, the Printer
MUST validate the fact that it supports the retrieval method (e.g.,
http, ftp, etc.) implied by the URI. If the Printer object supports
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this operation, it MUST support the "reference-uri-schemes-supported"
attribute (see section 4.4.21).
3.2.3 Validate-Job Operation
This 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. There are no Job Object Attributes returned in
the Validate-Job Response. If the Printer supports either the Print-
URI or Send-URI operations, the client MAY include a "document-uri"
attribute in the request. In this case, the Printer MUST validate
that the Printer supports the retrieval method implied by the URI, and
SHOULD check for validate URI syntax. The Printer NEED NOT follow the
reference and validate the contents of the reference. If all is well,
the Printer returns the status code "successful-ok". Otherwise, the
Printer returns a set of unsupported attributes and/or the appropriate
error status code. If the client supplies the "ipp-attribute-
fidelity" attribute set to false (or does not supply the attribute at
all) and if the Printer object returns a "successful-ok-ignored-or-
substituted-attributes", the Printer object SHOULD return all ignored
or substituted in the Unsupported Attributes group. In such a case,
the Printer object MUST return at least one attribute indicating an
unsupported attribute value or an ignored attribute.
3.2.4 Create-Job Operation
This 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", "content-charset", or
"content-natural-language" attributes. This operation is followed by
one or more Send-Document or Send-URI operations. In each of these
operation requests, the client OPTIONALLY supplies the "document-
name", "content-charset", or "content-natural-language" attributes for
each document in the multi-document Job. 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.
3.2.5 Get-Attributes Operation
The Printer Get-Attributes operation allows a client to obtain
information from a Printer object. In the operations attributes in a
request, the client supplies the set of attribute names and/or
attribute group names in which the requester is interested. In the
operation attribute in the response, the Printer returns a
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corresponding attribute set with the appropriate attribute values
filled in.
For Printers, the possible names of attribute groups are:
- 'job-template': all of the Job Template attributes that apply to
a Printer object (the last two columns of the table in Section
4.2).
- 'printer-description': the attributes specified in Section 4.4.
There is also the special group 'all' that includes all supported
attributes. 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', 'printer-description', and
'all', client is actually requesting the "printer-group, and once by
inclusion in the 'all' group. In all cases, the Printer SHALL only
return the attribute once in the response.
It is NOT REQUIRED that a Printer support all attributes belonging to
a group, however it is MANDATORY that each Printer implementation
understand all group names.
3.2.5.1 Get-Attributes Request
The following sets of attributes are part of the Get-Attributes
Request when the request is directed to a Printer object:
Group 1: Operation Attributes
Target:
The "printer-uri" target for this operation as described in
section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"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. If the client omits this attribute, the Printer
SHALL respond as if this attribute had been supplied with a value
of 'all'.
"document-format" (mimeType) :
The client OPTIONALLY supplies this attribute. This attribute is
useful for a Printer to determine the set of supported attribute
values that relate to the requested document format. The Printer
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SHOULD return only (1) those attributes that are supported for
that 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 to eliminate the
attributes and values that are not supported for a specific
document format. For example, a Printer 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 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'.
If the client omits this attribute, the Printer SHALL respond as
if the attribute had been supplied with a value set to the
Printer object's "document-format-default" default value
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 'mimeType' attribute
syntax in section 4.1.9.
NOTE: The "document-format" operation attribute is a fairly
sophisticated filtering notion that is not supported by many
existing print systems or devices.
3.2.5.2 Get-Attributes Response
The Printer object returns the following sets of attributes as part of
the Get-Attributes Response:
Group 1: Operation Attributes
Status Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
Group 2: Requested Printer Object Attributes
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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.
3.2.6 Get-Jobs Operation
The Get-Jobs operation allows a client to retrieve the list of Jobs
belonging to the target Printer object. The client may also supply a
list of Job attribute names or attribute group names. These Job
attributes will be returned for each Job that is returned.
This operation is similar Get-Attributes, except that this Get-Jobs
operation returns attributes from possibly more than one object (see
the description of attribute group names in section 3.3.4).
3.2.6.1 Get-Jobs Request
The client submits the Get-Jobs request to a Printer object.
The following groupsof attributes are part of the Get-Jobs Request:
Group 1: Operation Attributes
Target:
The "printer-uri" target for this operation as described in
section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"limit" (integer):
The client OPTIONALLY supplies this attribute. It is an integer
value that indicates a limit to the number of Job objects
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 will all applicable jobs.
"requested-attributes" (1setOf keyword):
The client OPTIONALLY supplies this attribute. It is a set of Job
attribute names or attribute groups names in whose values the
requester is interested. This set of attributes is returned for
each Job that is returned. The allowed attribute group names are
the same as those defined in the Get-Attributes operation for Job
objects. If the client does not supply this attribute, the
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Printer SHALL respond as if the client had supplied values of
'job-uri' and 'job-id'.
"which-jobs" (keyword):
The client OPTIONALLY supplies this attribute. It indicates which
Jobs should be returned by the Printer object. The values for
this attribute are:
'completed': This includes any Job object whose state is
'completed', 'cancelled', or 'aborted'.
'not-completed': This includes any Job object whose state is
'pending', 'processing', 'processing-stopped', 'pending-
held', 'unknown'.
If the client does not supply the attribute, the Printer object
SHALL respond as if the client had supplied the value of 'not-
completed'.
3.2.6.2 Get-Jobs Response
The Printer object returns all of the Job objects 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.
Group 1: Operation Attributes
Status Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
Groups 2 to N: Job Object Attributes
The Printer object responds with one set of Job Object Attributes
for each returned Job object.
For any job submitted in a different natural language than the
natural language that the client is requesting in the Get-Jobs
request, the Printer SHALL indicate the submitted natural
language by returning the "job-natural-language" as the first Job
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object attribute, which overrides the "attributes-natural-
language" operation attribute value being returned by the
Printer. If any returned 'text' or 'name' attribute includes an
exception natural language as described in the 'text' attribute
syntax (see Section 4.1.1), the exception natural language
overrides the "job-natural-language" value (for the immediately
following attribute value only).
Jobs are returned in the following order:
- If the client requests all 'completed' Jobs (Jobs in the
'completed', 'aborted', or 'cancelled' states), then the Jobs are
returned newest to oldest (with respect to actual completion
time)
- If the client requests all 'non-completed' Jobs (Jobs in the
'pending', 'processing', 'pending-held', 'processing-stopped',
and 'unknown' 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).
3.3 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. Since Job objects can be
identified with either a single Job URI or a combination of a Printer
URI with a local Job ID, the following rules apply to all Job
operation requests mapped onto HTTP/1.1:
- If the client chooses to identify Job objects with just the Job
URI, this "job-uri" attribute is not supplied in the body of the
operation as other operation attributes are. It is supplied in
the "request-URI" field in the HTTP header. - If the client
chooses to identify Job objects with both a Printer URI and a
local Job ID, the "printer-uri" attribute is not supplied in the
body of the operation, but it is supplied in the "request-URI"
field in the HTTP header. The "job-id" attribute is included as
an operation attribute.
Since the Get-Attributes operation can be both a Printer operation and
a Job operation, if a Printer object receives a Get-Attributes
request, the Printer object must check for the existence of the "job-
id" operation attribute. If present, the operation is intended to be
a Job operation on the corresponding Job object. If absent, the
operation is intended to be a Printer operation.
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3.3.1 Send-Document Operation
A client uses a Create-Job operation 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.
Since the Create-Job and the Send-Documents that follow can occur over
arbitrarily long periods of time, each Printer object must decide how
long to "wait" for the next Send-Document operation. The Printer
object OPTIONALLY supports the "multiple-operation-timeout" attribute.
This attribute indicates the maximum number of seconds the Printer
object will wait for the next Send-Document operation. If the Printer
object times-out waiting for the next Send-Document operation, the
Printer object MAY decide on any of the following semantic actions:
1. Assume that the Job is an invalid job, start the process of
changing the job state to 'aborted', and clean up all resources
associated with the Job. In this case, if another Send-Document
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 it finally
arrives.
2. Assume that the last Send-Document received was in fact the last
document (as if the "last-document" flag had been set to 'true'),
close the Job, and proceed to process it (i.e., move the Job's
state to 'pending').
3. Assume that the last Send-Document received was in fact the last
document, close the Job, but move it to the 'pending-held' to
allow an operator to determine whether or not to continue
processing the Job by moving it back to the 'pending' state.
Each implementation is free to decide the "best" action to take
depending on local policy, the value of "ipp-attribute-fidelity",
and/or any other piece of information available to it. If the choice
is to abort the Job, it is possible that the Job may already have been
processed to the point that some pages have been printed.
3.3.1.1 Send-Document Request
The following attribute sets are part of the Send-Document Request:
Group 1: Operation Attributes
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Target:
Either the "printer-uri" plus "job-id" or "job-uri" target for
this operation as described in section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"document-name" (name):
The client OPTIONALLY supplies this attribute, and 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.
"last-document" (boolean):
The client MUST supply this attribute. It is a boolean flag that
is set to 'true' if this is the last document for the Job,
'false' otherwise.
"document-charset" (charSet):
This attribute is OPTIONALLY supplied by the client. A Printer
object SHALL support this attribute if it supports a document-
format that requires a character set to be identified in order to
unambiguously interpret the document, such as 'text/plain'.
There are no particular values required for the Printer object to
support. This attribute specifies the charset of the document
for those document-formats that require a specification of the
charset in order to image the document unambiguously. If the
value of the "document-format" attribute contains a charset
parameter (see 'mimeType' attribute syntax in Section 4.1.9), the
client SHALL also supply the "document-charset" attribute and its
value SHALL be the same.
"document-natural-language" (naturalLanguage):
This attribute is OPTIONALLY supplied by the client. There are
no particular values required for the Printer object to support.
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,
such as proper glyph selection..
Group 2: Document Content
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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 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'.
3.3.1.2 Send-Document Response
The following sets of attributes are part of the Send-Document
Response:
Group 1: Operation Attributes
Status Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
Group 2: 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 operation is identical to the Send-Document operation (see
section 3.3.1) except that a client supplies 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.
The Printer object MUST validate the syntax of the supplied URI before
returning a response. If the Printer object supports this operation,
it MUST support the URI types defined under the Print-URI operation
(see section 3.2.2)
3.3.3 Cancel Job Operation
This operation allows a client to cancel a Print Job any time after a
create job operation.. Since a Job might already be printing by the
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time a Cancel-Job is received, some pages may be printed before the
job is actually terminated.
3.3.3.1 Cancel-Job Request
The following groups of attributes are part of the Cancel-Job Request:
Group 1: Operation Attributes
Target:
Either the "printer-uri" plus "job-id" or "job-uri" target for
this operation as described in section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"message" (text):
OPTIONAL message to the operator. This is not the same as the
"job-message-from-operator" attribute. This attribute is used to
send a message along with the operation request. It is an
implementation decision of how or where to display this message
(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 Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
Once a successful response has been sent, the implementation
guarantees that the Job will eventually end up in the 'cancelled'
state. If the implementation is forced to leave the job in the some
other state, the "job-state-reasons" SHOULD contain the ' processing-
to-stop-point ' value which indicates to later queries that although
the Job may still be 'processing', it will eventually end up in the
'cancelled' state, not the 'completed' state.
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3.3.4 Get-Attributes Operation
The Job Get-Attributes operation allows a client to obtain information
from a Job object and it is almost identical to the Get-Attributes
operation for a Printer object (see section 3.2.5). The only
differences are that the operation is directed at a Job rather than a
Printer and there is no "document-format" operation attribute used
when querying a Job object.
For Jobs, the attribute groups include:
- 'job-template': all of the Job Template attributes that apply to
a Job object (the first column of the table in Section 4.2).
- 'job-description': the attributes specified in Section 4.3.
There is also the special group 'all' that includes all supported
attributes. If for some reason, the client includes an attribute two
or more times in the request (e.g., the client supplies values of
'all', 'job-template', and 'sides' in the "requested-attributes"
attribute), the Printer SHALL only return one occurrence of the
attribute in the response.
3.3.4.1 Get-Attributes Request
The following groups of attributes are part of the Get-Attributes
Request when the request is directed at a Job object:
Group 1: Operation Attributes
Target:
Either the "printer-uri" plus "job-id" or "job-uri" target for
this operation as described in section 3.1.2.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.1.
"requested-attributes" (1setOf keyword) :
An OPTIONAL set of attribute names and/or attribute group names
in whose values the requester is interested. If the client omits
this attribute, the Printer SHALL respond as if this attribute
had been supplied with a value of 'all'.
3.3.4.2 Get-Attributes Response
The Printer object returns the following sets of attributes as part of
the Get-Attributes Response:
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Group 1: Operation Attributes
Status Code and Message:
The response includes the MANDATORY status code and an OPTIONAL
"status-message" (text) operation attribute as described in
section 3.1.4.
Natural Language and Character Set:
The "attributes-charset" and "attributes-natural-language"
attributes as described in section 3.1.3.2.
Group 2: Requested Job 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.
4. Object Attributes
This section describes the attributes with their corresponding
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 specifications:
- Document Printing Application (DPA) [ISODPA]
- RFC 1759 Printer MIB [RFC1759]
Each attribute is uniquely identified in this document using a
"keyword" (see section 12.2.1). The keyword is included in the
section header describing that attribute. All attributes are uniquely
identified with a keyword as its name. In addition, some attributes
are defined having a syntax that is a set of keywords.
4.1 Attribute Syntaxes
This section defines the basic attribute syntax types that a client
and server SHALL be able to handle. 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
SHALL include the semantics of the attribute syntax(es) so identified.
Section 6 describes how the protocol can be extended with new
attribute syntaxes.
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
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the value. Since each value SHALL 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.
The attribute syntaxes are specified in the following sub-sections,
where the sub-section heading is the name of the attribute syntax
inside the single quotes:
4.1.1 'text'
The 'text' attribute syntax is a sequence of one or more characters
with a limit of 1 to 4095 octets. The Printer object SHALL support
UTF-8 [RFC2044] and MAY support additional charsets provided that they
are registered with IANA [IANA-CS]. See Section 4.1.7 for the
specification of the 'charSet' attribute syntax, including restricted
semantics and examples of charsets.
If the client needs to pass or the Printer object needs to return a
'text' attribute in a different natural language than the rest of the
'text' attributes in the request or response as indicated by the
"attributes-natural-language" operation attribute (see Section 3.1.3),
the client or Printer object SHALL immediately precede that attribute
value with a 'naturalLanguage' attribute value that indicates the
differing natural language. Thus the attribute becomes multi-valued
with two values. This additional values is called an "exception"
natural language value. In a create operation, the Printer object
SHOULD accept and store an exception natural language value. If the
Printer object does not store an exception natural language value, the
Printer SHALL ignore it and SHALL store the immediately following
'text' value only. The Printer SHALL not reject the request no matter
what value the client supplies as an exception natural language.
If the attribute is multi-valued (1setOf text), then the exception
natural language value applies only to the next 'text' value.
Subsequent values in a multi-valued 'text' attribute in a request or a
response revert to the natural language of the operation attribute or
the "job-natural-language" job attribute, if present, in the case of a
Get-Jobs response.
Example: If the client supplies the "attributes-natural-language"
operation attribute with the value: 'en' indicating English, but the
values of the "job-name" attribute is in French, the values of the
normally single-valued "job-name" attribute supplied by the client in
any request or returned by the Printer object in any response would be
the following two values, each tagged with the appropriate attribute
syntax ('naturalLanguage' and 'text') in the protocol:
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'fr': exception natural language indicating French with attribute
syntax 'naturalLanguage'
'Rapport Mensuel': the job name in French with attribute syntax
'name'.
4.1.2 'name'
The 'name' attribute syntax is the same as 'text', including the
MANDATORY support of UTF-8 and the exception natural language
mechanism, except that the sequence of characters is limited so that
its encoded form is of length 1 to 255 octets. This syntax type is
used for user-friendly strings, such as a Printer name, that, for
humans, are more meaningful than identifiers.
Note: Only the 'text' and 'name attribute syntaxes permit the
exception natural language mechanism.
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 values of the normally
single-valued "printer-name" attribute returned by the Printer in any
operation response would be the following two values, each tagged with
the appropriate attribute syntax ('naturalLanguage' and 'name') in the
protocol:
'de': exception natural language indicating German with the
attribute syntax 'naturalLanguage'
'Farbdrucker': the Printer name in German with attribute syntax
'name'
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 SHALL 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 SHALL NOT use the exception natural language mechanism, since
they SHALL always be US-ASCII and U.S. English. When accepting
keywords from users and displaying keywords to users, clients SHOULD
localize the keywords to the charset and natural language of the user.
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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 SHALL 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 describes how
the protocol can be extended with new keyword values. Examples of
attribute name keywords:
"job-name"
"attributes-charset "
4.1.4 'enum'
The 'enum' attribute syntax is an enumerated integer value that is in
the range from -2**31 to 2**31 - 1. 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 specification are also used for
corresponding attributes in other standards [RFC1759].. This syntax
type is not used for attributes to which the system administrator may
assign values. Section 6 describes how the protocol can be extended
with new enum values. Though this document includes a symbolic name
for each enum value (in U.S. English), when accepting enum names from
users and displaying enum names to users, clients SHOULD localize the
names to the charset and natural language of the user.
4.1.5 'uri'
The 'uri' attribute syntax is any valid Uniform Resource Identifier or
URI [RFC1630]. Most often, URIs are simply Uniform Resource Locators
or URLs [RFC1738] [RFC1808].
4.1.6 'uriScheme'
The 'uriScheme' attribute syntax is a sequence of characters
representing a URI scheme according to RFC 1738 [RFC1738]. Standard
values for this syntax type are the following keywords:
'http': for HTTP schemed URIs (e.g., "http://...")
'ftp': for FTP schemed URIs (e.g., "ftp://...")
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'mailto': for SMTP schemed URIs (e.g., "mailto:...")
'file': for file schemed URIs (e.g., "file:...")
4.1.7 'charSet'
The 'charSet' attribute syntax is a standard identifier of a coded
character set and encoding scheme 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 [IANA-CSa]. As specified in RFC 2046, the
values SHALL be case-insensitive and SHALL be in US-ASCII. When a
character-set in the IANA registry has more than one name (alias), the
name labeled as "(preferred MIME name)" SHALL be used.
Some examples are:
'utf-8': ISO 10646 Universal Multiple-Octet Coded Character Set
(UCS) represented as the UTF-8 [RFC2044] transfer encoding scheme
in which US-ASCII is a subset charset. The 'utf-8' charset value
supplied in the "attributes-charset" operation attribute (see
Section 3.1.3), which is used to identify the charset of 'text'
and 'name' attributes, SHALL be restricted to conformance level 2
of ISO 10646 [ISO10646-1], so that accented letters SHALL NOT be
represented with non-spacing accents. This same 'utf-8' value
supplied in the "document-format" operation attribute (see
Sections 3.2.1.1 and 3.3.1.1), MAY include level 3 of ISO 10646.
'US-ASCII': 7-bit American Standard Code for Information
Interchange (ASCII), ANSI X3.4-1986 [ASCII]. This standard
defines US-ASCII, but RFC 2045 [46] 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]. This 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 MANDATORY values the 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 taken from RFC 1766 [RFC1766]. As specified in RFC 1766, the
values SHALL be case-insensitive and SHALL be in US-ASCII. Examples
include:
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'en': for English
'en-us': for US English
'FR': for French
'de': for German
4.1.9 'mimeType'
The 'mimeType' attribute syntax is the standard defined 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
parameter, depending on the specification of the Media Type in the
IANA Registry [IANA-MT]. Examples:
'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 SHALL 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 [RFC2044]
'text/plain, charset=iso-10646-ucs-2': A plain text document in
ISO 10646 represented in two octets (UCS-2) [ISO10646-1]
'application/postscript': A PostScript document [RFC2046]
'application/vnd.hp-PCL': A PCL document [IANA-MT] (charset escape
sequence embedded in the document data)
'application/octet-stream': Auto-sense - see below
One special type is 'application/octet-stream'. If the Printer
object supports this value, the Printer object or the device SHALL be
capable of auto-sensing the format of the document data. If the
Printer object's default value attribute 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 algorithm in the case of missing information not supplied by
the client. If the client supplies a document format value, the
Printer SHOULD 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 SHOULD trust
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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 SHOULD 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 SHOULD use its
auto-sensing mechanism whether auto-sensing is the Printer
object's default or not.
4.1.10 'octetString'
The 'octetString' attribute syntax is a sequence of octets. This
syntax type is used for opaque data
4.1.11 'boolean'
The 'boolean' attribute syntax is like a keyword with 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 to 2**31 - 1. Each individual attribute may specify
the range constraint explicitly if the range is different from the
full range of possible integer values (e.g., 0 - 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 set of two
integers, the smallest first, followed by the largest. The pair of
integers identifies an inclusive range of integer values.
4.1.14 'dateTime'
The 'dateTime' attribute syntax is a standard, fixed length
representation of the "DateAndTime" syntax as defined in RFC 1514
[RFC1514] and RFC 1903 [RFC1903]. When accepting 'dateTime' values
from users and displaying 'dateTime' values to users, clients SHOULD
localize the values to the charset and natural language of the user.
4.1.15 'resolution'
The 'resolution' attribute syntax specifies a two-dimensional
resolution in the indicated units. It consists of 3 integers: a cross
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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 dots per inch and 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.
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 SHALL 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 "foo":
1. The Printer object OPTIOINALLY supports a "foo-supported"
attribute that describes which job processing behaviors are
supported by that Printer object. A client can query the Printer
object to find out what foo-related behaviors are supported by
inspecting the returned values of the "foo-supported" attribute.
2. The Printer also OPTIONALLY supports a default value attribute
named "foo-default". This default value attribute describes what
will be done 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 the Printer supports either the "foo-
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default" default value attribute or the "foo-supported"
attribute, the Printer MUST support both.
3. "foo" is OPTIOINALLY supplied by the client in a create request.
If "foo" is supplied, the client is specifying that the Printer
SHALL apply the corresponding job processing behavior to this Job
while processing the Job. When "foo" is not supplied, the client
is specifying that the Printer apply the default job processing
behavior.
NOTE: Since an administrator MAY change the default value
attribute after a Job 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.
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 for the supported values. 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-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. If the client does supply the "finishings"
attribute in the create request, the Printer validates the value or
values to make sure that they are a subset of the supported values.
If the client-supplied values are all supported, the Job object is
created with a "finishings" attribute that is populated with the
values supplied by the client. Subsequently, when the Job object is
queried, it returns the values supplied by the client. If the client
does not supply a "finishings" attribute in the create request, the
Job object is created, but no "finishings" attribute is associated
with the new Job object. A subsequent query of the Job object will
return no "finishings" attribute. In this case, the querying client
knows that there were was no client supplied "finishings" attribute.
If the client is interested to know what the default value is that the
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Printer will use for the missing attribute, the client can query the
Printer object's default value "finishings-default" attribute to find
out how the Job will be finished.
The table below summarizes the names and relationships for all Job
Template attributes. The first column of the table (labeled "Job")
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" and "Printer: Supported Values") shows 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 SHALL NOT support the attribute
(that is the attribute is simply not applicable).
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+===================+======================+======================+
| Job Attribute |Printer: Default Value| Printer: Supported |
| | Attribute | Values Attribute |
+===================+======================+======================+
| job-sheets | job-sheets-default |job-sheets-supported |
| (type4 keyword, | (type4 keyword, |(1setOf type4 keyword,|
| name) | name) | name) |
| | | |
+-------------------+----------------------+----------------------+
| 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- |
| (type4 keyword, | default | supported |
| name) | (type4 keyword, |(1setOf type4 keyword,|
| name) | name) | name) |
+-------------------+----------------------+----------------------+
|multiple-document- |multiple-document- |multiple-document- |
| handling | handling-default |handling-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
+-------------------+----------------------+----------------------+
| media | media-default | media-supported |
| (type4 keyword, | (type4 keyword, |(1setOf type4 keyword,|
| name) | name) | name) |
| | | |
| | | media-ready |
| | |(1setOf type4 keyword,|
| | | name) |
| | | |
+-------------------+----------------------+----------------------+
| number-up | number-up-default | number-up-supported |
| (integer) | (integer) |(1setOf integer) |
| | | |
+-------------------+----------------------+----------------------+
| sides | sides-default | sides-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
| | | |
+-------------------+----------------------+----------------------+
| 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) |
+-------------------+----------------------+----------------------+
| finishings | finishings-default | finishings-supported |
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|(1setOf type2 enum)|(1setOf type2 enum) |(1setOf type2 enum) |
| | | |
+-------------------+----------------------+----------------------+
| copies | copies-default | copies-supported |
| (integer: 1:MAX) | (integer: 1:MAX) | (integer: 1:MAX) |
| | | |
| | | collated-copies- |
| | | supported |
| | | (integer: 1:MAX) |
| | | |
+-------------------+----------------------+----------------------+
| page-ranges | No | page-ranges- |
| (1setOf | | supported (boolean) |
| rangeOfInteger) | | |
+-------------------+----------------------+----------------------+
| orientation | orientation-default | orientation- |
| (type2 enum) | (type2 enum) | supported |
| | | (1setOf type2 enum) |
+-------------------+----------------------+----------------------+
| document-format | document-format- | document-format- |
| (mimeType) | default | supported |
| | (mimeType) |(1setOf mimeType) |
+-------------------+----------------------+----------------------+
| compression | No | compression-supported|
| (type3 keyword) | |(1setOf type3 keyword)|
| | | |
+-------------------+----------------------+----------------------+
| job-k-octets | No |job-k-octets-supported|
| (integer) | | (rangeOf integer) |
| | | |
+-------------------+----------------------+----------------------+
| job- | No | job-impressions- |
| impressions | | supported |
| (integer) | | (rangeOf integer) |
+-------------------+----------------------+----------------------+
| job-media- | No | job-media-sheets- |
| sheets | | supported |
| (integer) | | (rangeOf integer) |
+-------------------+----------------------+----------------------+
4.2.1 job-sheets (type4 keyword, name)
This attribute determines which if any banner page(s) SHALL be printed
with a job.
Standard values are:
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'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.
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4).
4.2.2 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 SHALL
print all jobs with a priority value of n before printing those with a
priority value of n-1 for all n.
The syntax for the "job-priority-supported" is an integer(1:100).
This single integer value indicates the number of priority levels
supported. For example, if the value of "job-priority-supported" is
'3', then the Printer object supports 3 levels of job priorities
(let's call them 'high', 'medium', and 'low'). In this case, a client
MUST assume the following:
A client supplied value in the range 1-33 is the same as any other
value in the range 1-33 and any one of those values corresponds
to the 'low' priority.
A client supplied value in the range 34-66 is the same as any other
value in the range 34-66 and any one of those values corresponds
to the 'medium' priority.
A client supplied value in the range 67-100 is the same as any
other value in the range 67-100 and any one of those values
corresponds to the 'high' priority.
For another example, if the value of "job-priority-supported" is '10',
then the Printer object supports 3 levels of job priorities, (let's
call them 'one', 'two', ..., and 'ten' with 'one' being the lowest
priority and 'ten' being the highest). In this case, a client MUST
assume the following:
A client supplied value in the range 1-10 is the same as any other
value in the range 1-10 and any one of those values corresponds
to the 'one' priority.
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A client supplied value in the range 11-20 is the same as any other
value in the range 11-20 and any one of those values corresponds
to the 'two' priority.
...
A client supplied value in the range 91-100 is the same as any
other value in the range 91-100 and any one of those values
corresponds to the 'ten' priority.
4.2.3 job-hold-until (type4 keyword, name)
This job attribute specifies the named time period during which the
Job SHALL become a candidate for printing.
Standard values for named time periods are:
'no-hold': immediately, if there are not other reasons to hold the
job.
'day-time': during the day.
'evening': evening
'night': night
'weekend': weekend
'second-shift': second-shift
'third-shift': third-shift (after midnight)
An administrator SHALL associate allowable print times with a named
time period (by means outside IPP 1.0). 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 SHALL add the 'job-hold-until-specified' value to
the job's "job-state-reasons" attribute, move the job to the 'pending-
held' state, and SHALL NOT schedule the job for printing until the
specified time-period arrives. When the specified time period
arrives, the Printer SHALL remove the 'job-hold-until-specified' value
from the job's "job-state-reason" attribute and, if no other job
reasons that keep it in the 'pending-held' state remain, the Printer
SHALL 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 specified
time period is in effect has already started, the job SHALL be a
candidate for processing immediately.
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4.2.4 multiple-document-handling (type2 keyword)
This job attribute is relevant only if a job consists of two or more
documents. The attribute controls finishing operations and the
placement of print-stream pages into imposed pages 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 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) SHALL be treated as a single
sequence of media sheets for finishing operations; that is,
finishing would be performed on the concatenation of the
seqeunces a(*),b(*). The Printer SHALL NOT force the data in
each document instance to be formatted onto a new print-stream
page, nor to start a new imposed page or 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 SHALL be a(*),
b(*), a(*), b(*),...., and the Printer SHALL force each copy to
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 SHALL
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 SHALL force each copy of the
result of process 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
SHALL 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 SHALL be
treated as a single sequence of media sheets for finishing
operations; that is, the sets a(*) and b(*) would each be
finished separately. If more than one copy is made, the ordering
of the sets of media sheets resulting from processing the
document data SHALL be a(*), b(*), a(*), b(*), ...., and the
Printer SHALL force each document copy to start on a new sheet .
'separate-documents-collated-copies' is the same as 'single-document'
with respect to ordering of pages, but not media sheet generation,
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since the latter 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 the former case always force the next document
or document copy on to a new sheet.
4.2.5 media (type4 keyword, name)
This job attribute identifies the medium that the Printer uses for all
pages 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 allows a client to specify a medium name as the value of this
attribute, such a medium name implicitly selects an input-tray that
contains the specified medium. If a printer allows a client to
specify a medium size as the 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 allows a client to specify 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 allows a client to specify 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 SHALL merge with the document data as its prints each page.
Standard values are (taken from ISO DPA and the Printer MIB) 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 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.
The relationship of this attribute and the other attributes that
control document processing is described in section 15.4.
4.2.6 number-up (integer)
This job attribute specifies the number of source page-images to
impose upon a single side of an instance of a selected medium. For
example, if the value is
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'1': The Printer SHALL place one logical page on a single side of
an instance of the selected medium (MAY add some sort of
translation, scaling, or rotation).
'2': The Printer SHALL place two logical pages on a single side of
an instance of the selected medium (MAY add some sort of
translation, scaling, or rotation).
'4': The Printer SHALL place four logical 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 page images, but a site may choose to add embellishments,
such as borders to each logical page.
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 15.4.
ISSUE: Steve Z.: should this section be changed to include "print-
stream page" and "layout page"?? rather than "source page" and
"logical page"?
4.2.7 sides (type2 keyword)
This attribute specifies how source page-images are to be imposed upon
the sides of an instance of a selected medium.
The standard values are:
'one-sided': imposes each consecutive source page-image upon the
same side of consecutive media sheets.
'two-sided-long-edge': imposes each consecutive pair of source
page-image upon front and back sides of consecutive media sheets,
such that the orientation of each pair of source-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 source
page-image upon front and back sides of consecutive media sheets,
such that the orientation of each pair of source-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
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switches between 'duplex' and 'tumble' when using portrait and
landscape modes.
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 15.4.
4.2.8 printer-resolution (resolution)
This attribute identifies the resolution that Printer uses for a
certain Job.
4.2.9 print-quality (type2 enum)
This attribute specifies the print quality that the Printer SHALL use
for a certain Job.
The standard values are:
'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
4.2.10 finishings (1setOf type2 enum)
This attribute identifies the finishing operations that the Printer
uses for each copy of each printed document in a particular Job. For
Jobs with multiple documents, the "multiple-document-handling"
attribute determines what constitutes a _copy_ for purposes of
finishing.
Standard values are:
'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
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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."
Note: The effect of this attribute on jobs with multiple documents is
controlled by the "multiple-document-handling" job attribute (section
4.2.4).
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).
4.2.11 copies (integer(1:2**31 - 1))
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. The
"copies-supported" attribute is the limit on the number of uncollated
copies supported. The "collated-copies-supported" attribute is the
limit on the number of collated copies supported. The value in the
"copies-default" default value attribute applies to either collated or
uncollated as determined by the value in the "multiple-document-
handling-default" attribute.
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 15.4.
4.2.12 page-ranges (1setOf rangeOfInteger)
This attribute specifies the pages of a document which are to be
printed. 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-
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ranges-default" attribute. If the "page-ranges" attribute is not
supplied by the client, all pages of the document will be printed.
4.2.13 orientation (type2 enum)
This attribute specifies the orientation of the content on the output
pages to be printed. In most cases, the orientation of the content is
specified within the document format generated by the device driver at
print time. However, some document formats (such as 'text/plain') do
not support the notion of page orientation, and it is possible to bind
the orientation after the document content has been generated. This
attribute provides an end user with the means to specify orientation
for such documents.
Standard values are:
'1' 'portrait': The content will be imaged across the short
edge of the medium.
'2' 'landscape': The content will be imaged across the long
edge of the medium. Landscape is defined to be a
rotation of the logical 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
'3' 'reverse-landscape': The content will be imaged across the
long edge of the medium. Reverse-landscape is defined
to be a rotation of the logical 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.
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 15.4.
4.2.14 document-format (mimeType)
This attribute identifies the document format of the data to be
printed. The standard values for this attribute are Internet Media
types which are sometimes called MIME types. See the description of
the 'mimeType' attribute syntax in Section 4.1.9.
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4.2.15 compression (type3 keyword)
This attribute identifies compression algorithms used on compressed
document data. The value of this attribute does not apply the
encoding of the IPP operation itself.
Standard values are :
'none': no compression is used.
'deflate': ZIP public domain inflate/deflate) compression
technology
`gzip' GNU zip compression technology described in RFC 1952.
'compress': UNIX compression technology
4.2.16 job-k-octets (integer(0:2**31 - 1))
This attribute specifies the total size of the document data in K
octets, i.e., in units of 1024 octets requested to be processed in
the job. The value SHALL be rounded up, so that a job between 1 and
1024 octets SHALL be indicated as being 1, 1025 to 2048 SHALL be 2,
etc.
This value SHALL 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 document data and independent of whether the
output is collated or not. Thus the value is independent of the
implementation.
Note: This attribute and the following two attributes ("job-
impressions" and "job-media-sheets") are not intended to be counters;
they are intended to be useful routing and scheduling information if
known. For these three attributes, the Printer may try to compute the
value if it is not supplied in the create request. Even if the client
does supply a value for this attribute in the create request, the
Printer may choose to change the value if the Printer is able to
compute a value which is more accurate than the client supplied value.
The Printer may be able to determine the correct value for this
attribute either right at job submission time or at any later point in
time. If the value of this attribute is unknown, the Printer may
choose to respond with a value of '-2' (which signifies "unknown")
rather than choose to not support the attribute at all.
4.2.17 job-impressions (integer(0:2**31 - 1))
This attribute specifies the total number of impressions of the
document(s) being requested by this job to produce.
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This value SHALL 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 document data and independent of whether the
output is collated or not. Thus the value is independent of the
implementation.
4.2.18 job-media-sheets (integer(0:2**31 - 1))
This attribute specifies the total number of media sheets to be
processed for this job.
Unlike the "job-k-octets" and the "job-impressions" attributes, this
value SHALL include the multiplicative factors contributes by the
number of copies specified by the "copies" attribute
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 MANDATORY attribute
that MUST be supported by Printer objects. If it is not MANDATORY,
then it is OPTIONAL.
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+----------------------------+----------------------+----------------+
| Attribute | Syntax | MANDATORY? |
+----------------------------+----------------------+----------------+
| job-uri | uri | MANDATORY |
+----------------------------+----------------------+----------------+
| job-id | integer(1:MAX) | MANDATORY |
+----------------------------+----------------------+----------------+
| job-more-info | uri | |
+----------------------------+----------------------+----------------+
| job-name | name | MANDATORY |
+----------------------------+----------------------+----------------+
| job-originating-user | octetString | MANDATORY |
+----------------------------+----------------------+----------------+
| job-state | type1 enum | MANDATORY |
+----------------------------+----------------------+----------------+
| job-state-reasons | 1setOf type2 keyword | |
+----------------------------+----------------------+----------------+
| job-state-message | text | |
+----------------------------+----------------------+----------------+
| number-of-documents | integer | |
+----------------------------+----------------------+----------------+
| output-device-assigned | name | |
+----------------------------+----------------------+----------------+
| time-of-creation | integer | |
+----------------------------+----------------------+----------------+
| time-at-processing | integer | |
+----------------------------+----------------------+----------------+
| time-at-completed | integer | |
+----------------------------+----------------------+----------------+
| number-of-intervening-jobs | integer | |
+----------------------------+----------------------+----------------+
| job-message-from-operator | text | |
+----------------------------+----------------------+----------------+
| job-k-octets-processed | integer | |
+----------------------------+----------------------+----------------+
| job-impressions-completed | integer | |
+----------------------------+----------------------+----------------+
| job-media-sheets-completed | integer | |
+----------------------------+----------------------+----------------+
| attributes-charset | charSet | MANDATORY |
+----------------------------+----------------------+----------------+
| attributes-natural-language| naturalLanguage | MANDATORY |
+----------------------------+----------------------+----------------+
4.3.1 job-uri (uri)
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This attribute contains the URI for the job. The Printer, on receipt
of a new job, generates a URI which identifies the new Job on that
Printer. The Printer returns the value of the "job-uri" attribute as
part of the response to a create request. This MUST be an HTTP
schemed URI, however the precise format of a Job URI is implementation
dependent.
For a description of this attribute and its relationship to the
following "job-id" attribute, see the discussion in section 2.4 on
"Object Identity".
4.3.2 job-id (integer(1:MAX))
This 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.
For a description of this attribute and its relationship to the
previous "job-uri" attribute, see the discussion in section 2.4 on
"Object Identity".
4.3.3 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.
4.3.4 job-name (name)
This 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. If, however, if the "job-name" operation
attribute is not supplied by the client in the create request, the
Printer, on creation of the Job, SHALL 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-URI" attribute of the first (or only) document, 2) the
"document-name" operation attribute of the first (or only) document,
or 3) any other piece of Job specific information.
4.3.5 job-originating-user (octetString)
This attribute contains the identity of the end user that submitted
the print job. The Printer object sets this attribute to the most
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authenticated name that it can obtain from the authentication service
over which the IPP operation was received.
4.3.6 job-state (type1 enum)
This attribute identifies the current state of the job. Even though
the IPP protocol defines eight values for job states, 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 values are:
'unknown'(2): The job state is not known, or its state is
indeterminate.
'pending'(3): The job is a candidate to start processing, but is
not yet processing.
'pending-held'(4): 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 SHALL indicate why the job is no longer a
candidate for processing.
'processing'(5): 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 server 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.
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 device is actually making marks on a medium.
When the job is in the 'processing' state, the entire job state
includes the detailed status represented in the printer's
"printer-state", "printer-state-reasons", and "printer-state-
message" attributes.
Implementations MAY 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
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'processing-to-stop-point' value to indicate that the server or
device is in the process of canceling or aborting the job. Most
implementations won't bother with this nuance.
'processing-stopped'(6): 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's "printer-state", "printer-state-
reasons" and "printer-state-message" attributes.
'canceled'(7): The job has been canceled by a Cancel-Job operation
and the Printer has completed canceling the job and all job
status attributes have reached their final values for the job.
While the Printer is canceling the job, 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.
'aborted'(8): 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 server or device is aborting the job, the job's "job-
state-reasons" attribute MAY contain the 'processing-to-stop-
point' and 'aborted-by-system' values. If supported, the
'aborted-by-system' value SHALL remain while the job is in the
'aborted' state.
'completed'(9): 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). 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 SHALL 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.
The following figure shows the normal job state transitions.
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+----> 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 job-state-reasons (1setOf type2 keyword)
This attribute provides additional information about the job's current
state, i.e., information that augments the value of the job's "job-
state" attribute.
Implementation of these values is OPTIONAL, i.e., a Printer NEED NOT
implement them, even if (1) the output device supports the
functionality represented by the reason and (2) is available to the
Printer object implementation. These values MAY be used with any job
state or states for which the reason makes sense. Furthermore, when
implemented, the Printer SHALL return these values when the reason
applies and SHALL 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 Printer MAY set the value of the Job's "job-state-reasons"
attribute to '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 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.
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'job-incoming': The CreateJob operation has been accepted by the
Printer, but the Printer is expecting additional Send-Document
and/or Send-URI operations and/or is accessing/accepting document
data.
'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.
'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 SHALL NOT be a candidate for processing
until this reason is removed and there are no other reasons to
hold the job.
'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.
'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-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 name is
the same as the value of the job's "job-originating-user"
attribute, or by some other authorized end-user, such as a member
of the job owner's security group.
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'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).
'job-canceled-at-device': The job was canceled by an unidentified
local user, i.e., a user at a console at the device.
'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.
'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.
This reason is recommended to be used in conjunction with the
'processing' job state to indicate that the Printer object is
still performing some actions on the job while the job remains in
the 'processing' 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.
'job-completed-with-warnings': The job completed with warnings.
'job-completed-with-errors': The job completed with errors (and
possibly warnings too).
4.3.8 job-state-message (text)
This attributes specifies supplemental information about the Job State
in human readable text. The Printer object SHALL be able to generate
this message in any of the natural languages identified by the
Printer's "natural-language-supported" attribute (see the "attributes-
natural-language" operation attribute specified in Section 3.1.3.1).
4.3.9 number-of-documents (integer(0:2**31 - 1))
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 or not.
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Implementations supporting the OPTIONAL Create-Job/Send-Document/Send-
URI operations SHOULD support this attribute.
4.3.10 output-device-assigned (name)
This attribute identifies the Output Device to which the Printer has
assigned this job. If an output device implements an embedded IPP
Printer, the Printer NEED NOT set this attribute. If a Print Server
implements a Printer, the value MAY be empty until the Printer assigns
an output device to the job.
4.3.11 time-of-creation (integer)
This attribute indicates the point in time at which the Job object was
created. In order to populate this attribute, the Printer object uses
the value in its "printer-up-time" attribute at the time the Job
object is created.
4.3.12 time-at-processing (integer)
This attribute indicates the point in time at which the Job object
began processing. In order to populate this attribute, the Printer
object uses the value in its "printer-up-time" attribute at the time
the Job object is moved into the 'processing' state for the first
time.
4.3.13 time-at-completed (integer)
This attribute indicates the point in time at which the Job object
completed (or was cancelled or aborted). In order to populate this
attribute, the Printer object uses the value in its "printer-up-time"
attribute at the time the Job object is moved into the 'completed' or
'canceled' or 'aborted' state.
4.3.14 number-of-intervening-jobs (integer(0:2**31 - 1))
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.
4.3.15 job-message-from-operator (text)
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.
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4.3.16 job-k-octets-processed (integer(0:2**31 - 1))
This attribute specifies the number of octets processed in K octets,
i.e., in units of 1024 octets. The value SHALL be rounded up, so that
a job between 1 and 1024 octets SHALL be indicated as being 1, 1025 to
2048 SHALL be 2, etc.
For implementations where multiple copies are produced by the
interpreter with only a single pass over the data, the final value
SHALL 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 SHALL be a
multiple of the value of the "job-k-octets" attribute.
Note: This attribute and the following two attributes ("job-
impressions-completed" and "job-sheets-completed") are intended to be
counters. That is, if the "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.
For any of these three attributes, the Printer may choose to return
the value '-2' (which represents "unknown") rather than choose to not
support the attribute at all.
4.3.17 job-impressions-completed (integer(0:2**31 - 1))
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. This
attribute is intended to be a counter as in the Job Monitoring MIB.
For implementations where multiple copies are produced by the
interpreter with only a single pass over the data, the final value
SHALL be equal to the value of the "job-impressions" attribute. For
implementations where multiple copies are produced by the interpreter
by processing the data for each copy, the final value SHALL be a
multiple of the value of the "job-impressions" attribute.
4.3.18 job-media-sheets-completed (integer(0:2**31 - 1))
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. This attribute is intended to be a
counter as in the Job Monitoring MIB.
4.3.19 attributes-charset (charSet)
This attribute is populated using the value in the client supplied
"attributes-charset" attribute in the create request. It identifies
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the charset (coded character set and encoding method) used for any Job
attributes with attribute syntax 'text' and 'name' whether supplied by
the client and/or returned by the Printer object. See Section 3.1.3
for a complete description of the "attributes-charset" operation
attribute.
4.3.20 attributes-natural-language (naturalLanguage)
4.4 This 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' whether supplied by the client
and/or returned by the Printer object. See Section 3.1.3 for a
complete description of the "attributes-natural-language" operation
attribute. See Section 4.1.1 for how an exception natural languages
may be supplied explicitly for each 'text' and 'name' attribute value
that differs from the value identified by the "job-natural-language"
attribute.Printer Description Attributes
These attributes form the attribute group called "printer-
description". A Printer object may be realized in either a print
server or output device. Note: How these attributes are set by an
Administrator is outside the scope of this specification. The
following table summarizes these attributes, their syntax, and whether
or not they are MANDATORY for a Printer object to support. If they
are not MANDATORY, they are OPTIONAL.
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+----------------------------+----------------------+----------------+
| Attribute | Syntax | MANDATORY? |
+----------------------------+----------------------+----------------+
| printer-uri | uri | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-name | name | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-location | text | |
+----------------------------+----------------------+----------------+
| printer-info | text | |
+----------------------------+----------------------+----------------+
| printer-more-info | uri | |
+----------------------------+----------------------+----------------+
| printer-driver-installer | uri | |
+----------------------------+----------------------+----------------+
| printer-make-and-model | text | |
+----------------------------+----------------------+----------------+
| printer-more-info- | uri | |
| manufacturer | | |
+----------------------------+----------------------+----------------+
| printer-state | type1 enum | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-state-reasons | 1setOf type2 keyword | |
+----------------------------+----------------------+----------------+
| printer-state-message | text | |
+----------------------------+----------------------+----------------+
| operations-supported | 1setOf operation | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-charset | charSet | MANDATORY |
+----------------------------+----------------------+----------------+
| charsets-supported | 1setOf charSet | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-natural-language | naturalLanguage | MANDATORY |
+----------------------------+----------------------+----------------+
| natural-languages-supported| 1setOf | MANDATORY |
| | naturalLanguage | |
+----------------------------+----------------------+----------------+
| printer-is-accepting-jobs | boolean | MANDATORY |
+----------------------------+----------------------+----------------+
| queued-job-count | integer | |
+----------------------------+----------------------+----------------+
| printer-message-from- | text | |
| operator | | |
+----------------------------+----------------------+----------------+
| color-supported | boolean | |
+----------------------------+----------------------+----------------+
| pdl-override | type2 keyword | MANDATORY |
+----------------------------+----------------------+----------------+
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| security-mechanisms- | 1setOf keyword | |
| supported | | |
+----------------------------+----------------------+----------------+
| printer-up-time | integer | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-current-time | dateTime | |
+----------------------------+----------------------+----------------+
| multiple-operation-time-out| integer | |
+----------------------------+----------------------+----------------+
4.4.1 printer-uri (uri)
This attribute contains the URI for the printer. An administrator
determines a printer's URI and sets this attribute to that URI. This
MUST be an HTTP schemed URI, however the precise format of a printer
URI is implementation dependent.
4.4.2 printer-name (name)
This attribute contains the name of the printer. It is a name that is
more user friendly than the printer-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.
4.4.3 printer-location (text)
This attribute identifies the location of this printer. This could
include things like: _in Room 123A, second floor of building XYZ_.
4.4.4 printer-info (text)
This attribute identifies the descriptive information about this
Printer. 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".
4.4.5 printer-more-info (uri)
This attribute contains a URI used to obtain more information about
this specific printer. 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
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site specific services (e.g. job pricing, services offered, end user
assistance). The device manufacturer may initially populate this
attribute.
4.4.6 printer-driver-installer (uri)
This attribute contains a URI to use to locate the driver installer
for this printer. This attribute is intended for consumption by
automata. The mechanics of print driver installation is outside the
scope of IPP. The device manufacturer may initially populate this
attribute.
4.4.7 printer-make-and-model (text)
This attribute identifies the make and model of the printer.
4.4.8 printer-more-info-manufacturer (uri)
This attribute contains a URI used to obtain more information about
this type of printer. 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). 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.
4.4.9 printer-state (type1 enum)
This attribute identifies the current state of the printer. 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. A Printer NEED NOT implement all
values if they are not applicable to a given implementation.
The following standard values are defined:
'unknown'(2): The Printer state is not known, or is indeterminate.
A Printer SHALL use this state only if it cannot determine its
actual state.
'idle'(3): If a Printer receives a job (whose required resources
are ready) while in this state, such a job SHALL transit into the
processing state immediately. If the printer-state-reasons
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attribute contains any reasons, they SHALL be reasons that would
not prevent a job from transiting into the processing state
immediately, e.g., toner-low. Note: if a Printer controls more
than one output device, the above definition implies that a
Printer is idle if at least one output device is idle.
'processing'(4): If a Printer receives a job (whose required
resources are ready) while in this state, such a job SHALL
transit into the pending state immediately. Such a job SHALL
transit into the processing state only after jobs ahead of it
complete. If the printer-state-reasons attribute contains any
reasons, they SHALL be reasons that do not prevent the current
job from printing, e.g. toner-low. Note: if a Printer controls
more than one output device, the above definition implies that a
Printer is processing if at least one output device is
processing, and none is idle.
'stopped'(5): If a Printer receives a job (whose required
resources are ready) while in this state, such a job SHALL
transit into the pending state immediately. Such a job SHALL
transit into the processing state only after some human fixes the
problem that stopped the printer and after jobs ahead of it
complete printing. The "printer-state-reasons" attribute SHALL
contain at least one reason, e.g. media-jam, which prevents it
from either processing the current job or transiting a pending
job to the processing state.
Note: if a Printer controls more than one output device, the
above definition implies that a Printer is stopped only if all
output devices are stopped. Also, it is tempting to define
stopped as when a sufficient number of output devices are stopped
and leave it to an implementation to define the sufficient
number. But such a rule complicates the definition of stopped
and processing. For example, with this alternate definition of
stopped, a job can move from idle to processing without human
intervention, even though the Printer is stopped.
4.4.10 printer-state-reasons (1setOf type2 keyword)
This attribute supplies additional detail about the printer's state.
Each 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
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serve as a precursor to a warning. A report SHALL 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 SHALL
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 SHALL include all errors. If this attribute
contains one or more errors, printer SHALL be in the stopped
state.
If the implementation does not add any one of the three suffixes, all
parties SHALL 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 values are defined:
'other': The printer has detected an error other than one listed in
this document.
'unknown': The printer is unable to give additional detail about
the state of the printer. This state reason is semantically
equivalent to printer-state-reasons without any value.
'media-needed': A tray has run out of media.
'media-jam': The printer has a media jam.
'paused': Someone has paused the Printer. In this state, a Printer
SHALL not produce printed output, but it SHALL perform other
operations requested by a client. If a Printer had been printing
a job when the Printer was paused, the Printer SHALL resume
printing that job when the Printer is no longer paused and leave
no evidence in the printed output of such a pause.
'shutdown': Someone has removed a Printer from service, and it may
be powered down or physical removed. In this state, a Printer
SHALL not produce printed output, and unless the Printer is
realized by a print server that is still active, the Printer
SHALL perform no other operations requested by a client,
including returning this value. If a Printer 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
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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 server has scheduled a job on the
Printer 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 will be stopping in a while and will change
its reason to printer-stopped. This reason is a non-critical,
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 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 Printer is low on toner.
'marker-supply-low': The Printer is low on marker supply (ink,
paint, etc.).
'spool-area-full': The limit of persistent storage allocated for
spooling has been reached.
'cover-open': One or more covers on the printer is open.
'interlock-open': One or more interlock devices on the printer is
unlocked.
'door-open': One or more doors on the printer are open.
'input-tray-missing': One or more input trays are not in the
printer.
'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
printer
'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 Printer is low on at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-supply-empty: The Printer is out of at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-waste-almost-full': The Printer marker supply waste
receptacle is almost full.
'marker-waste-full': The Printer marker supply waste receptacle is
full.
'fuser-over-temp': The fuser temperature is above normal.
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'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 Printer is low on developer.
'developer-empty: The Printer is out of developer.
'interpreter-resource-unavailable': An interpreter resource is
unavailable (i.e. font, form)
4.4.11 printer-state-message (text)
This attribute specifies the additional information about the printer
state and printer state reasons in human readable text. The Printer
object SHALL be able to generate this message in any of the natural
languages identified by the Printer's "natural-language-supported"
attribute (see the "attributes-natural-language" operation attribute
specified in Section 3.1.3.1).
4.4.12 operations-supported (1setOf operation)
This attribute specifies the set of supported operations for this
Printer. The syntax of type of "operation" is the same as "type2
enum" except that the range of values is 0x0000 to 0x8FFF.
The following standard values are defined:
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
0x000A Get-Jobs
0x0009 Get-Attributes
0x000A-0x3FFF reserved for future operations
0x4000-0x8FFF reserved for private extensions
This allows for certain vendors to implement private extensions that
are guaranteed to not conflict with future registered extensions.
However, there is no guarantee that two or more private extensions
will not conflict.
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4.4.13 printer-charset (charSet)
This MANDATORY 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-charset" attribute SHALL also be
among the values of the Printer's "charset-supported" attribute.
4.4.14 charsets-supported (1setOf charSet)
This MANDATORY attribute identifies the set of charsets that the
Printer object supports in attributes with attribute syntax 'text' and
'name', i.e., that the Printer object SHALL (1) accept in requests,
(2) return in responses, and (3) send in notification messages. At
least the value 'utf-8' SHALL be present, since a Printer object SHALL
support the UTF-8 [RFC2044] charset.
If more charsets than UTF-8 are supported, the Printer object SHALL
perform charset conversion between the charsets as described in
Section 3.1.3.1.
4.4.15 printer-natural-language (naturalLanguage)
This MANDATORY 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
3.1.3.1 for the specification of the OPTIONAL multiple natural
language support. Therefore, the value of the "printer-natural-
language" attribute SHALL also be among the values of the Printer's
"natural-language-supported" attribute.
4.4.16 natural-languages-supported (1setOf naturalLanguage)
This MANDATORY attribute identifies the natural language(s) that the
Printer object supports in attributes with attribute syntax 'text' and
'name', i.e., that the Printer object SHALL (1) accept in requests,
(2) return in responses, and (3) send in notification messages. The
natural language(s) supported depends on implementation and/or
configuration.
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For any of the attributes for which the Printer generates messages,
i.e., for the "job-state-message" and "printer-state-message"
attributes and Operation Messages (see Section 3.1.4) in operation
responses, the Printer object SHALL be able to generate messages in
any of its supported natural languages. See section 3.1.3.1 for the
specification 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.
4.4.17 printer-is-accepting-jobs (boolean)
This attribute indicates whether the printer is currently accepting
job. If the value is true, the printer is accepting jobs. If the
value is false, the printer is currently rejecting any jobs submitted
to it.
Note: This value is independent of the printer state and printer-
state-reasons because its value does not affect the current job;
rather it affects future jobs. This attribute may cause the Printer to
reject jobs when the printer-state is idle or it may cause the Printer
to accepts jobs when the printer-state is stopped.
4.4.18 queued-job-count (integer(0:2**31 - 1))
This 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.
4.4.19 printer-message-from-operator (text)
This 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.
4.4.20 color-supported (boolean)
This attribute identifies whether the Printer is capable of any type
of color printing at all. All document instructions having to do with
color are embedded within the document PDL (none are external IPP
attributes).
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4.4.21 reference-uri-schemes-supported (1setOf uriScheme)
This 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 URIs of the following type:
'http': The Printer object will perform an HTTP/1.1 GET operation
'ftp': The Printer object will use an FTP 'get' operation. If the
URI does not indicate a name or password in the URI itself, the
Printer object will use anonymous FTP generating (if prompted)
some password in the form of an Internet mail address.
The Printer object OPTIONALLY supports other URI schemes (see section
4.1.6).
4.4.22 pdl-override (type2 keyword)
This attribute expresses the ability for a particular Printer
implementation to either attempt to override document data
instructions with IPP attributes or not.
This MANDATORY attribute takes on the following values:
- 'attempted': This value indicates that the Printer attempts to
make sure that 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 makes no
attempt to ensure that IPP attribute values take precedence over
embedded instructions in the print data.
Section 15 contains a full description of how this attribute interacts
with and affects other IPP attributes, especially the "ipp-attribute-
fidelity" attribute.
4.4.23 security-mechanisms-supported (1setOf keyword)
This attribute indicates the security mechanisms supported. Standard
values are:
'tls': Transport Layer Security (TLS)
'ssl': Secure Sockets Layer (SSL)
'http-digest': HTTP/1.1 Digest Authentication
'http-basic': HTTP/1.1 Basic Authentication
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4.4.24 printer-up-time (integer(1:MAX))
This attribute is a MANDATORY attribute. It indicates the amount of
time (in seconds) that this instance of this Printer implementation
has been up and running. This value is used to populate the Job
attributes "time-of-creation", "time-at-processing", and "time-at-
completed". These time values are all measured in seconds and all
have meaning only relative to this attribute, "printer-up-time". The
value is a monotonically increasing value starting from 1 when the
Printer object is started-up (initialized, booted, etc.).
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 the first case, the Printer SHOULD not tweak any existing related
Job attributes ("time-of-creation", "time-at-processing", and "time-
at-completed"). In the second case, the Printer object SHOULD be
reset to 0. If a client queries a time-related Job attribute and
finds the value to be 0, the client MUST assume that the Job was
submitted in some life other than the Printer's current life.
4.4.25 printer-current-time (dateTime)
This attribute is an OPTIONAL attribute. It indicates the current
absolute wall-clock time. If an implementation supports this
attribute, then a client could calculate the absolute wall-clock time
each Job's "time-of-creation", "time-at-processing", and "time-at-
completed" attributes by using both "printer-up-time" and this
attribute, "printer-current-time". If an implementation does not
support this attribute, a client can only calculate the relative time
of certain events based on the MANDATORY "printer-up-time" attribute.
4.4.26 multiple-operation-time-out (integer)
This attributes identifies how long (in seconds) the Printer object
waits for additional Send-Document or Send-URI operations to follow a
still-open multi-document Job object.
5. Conformance
This section describes conformance issues and requirements. This
document introduces model entities such as objects, operations,
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attributes, and attribute values. These conformance sections describe
the conformance requirements which apply to these model entities.
5.1 Client Conformance Requirements
A conforming client SHALL send operations that conform to the protocol
defined in _Internet Printing Protocol/1.0: Protocol Specification_
[IPP-PRO]. For each attribute included in an operation request, a
conforming client SHALL send a value whose type and value syntax
conforms to the requirement of this document
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. 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.
When sending a Get-Attributes or create request, an IPP client NEED
NOT supply any OPTIONAL attributes.
A client SHALL 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.
A query response may contain attributes and values 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 extended registered or private
attributes and/or attribute values that conform to Section 6. Clients
may choose to ignore any parameters, attributes, or values that it
does not understand.
5.2 Printer Object Conformance Requirements
This section specifies the conformance requirements for conforming
Printer object implementations with respect to objects, operations,
and attributes.
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5.2.1 Objects
Conforming Printer implementations SHALL implement all of the model
objects as defined in this specification in the indicated sections:
Section 2.1 Printer Object
Section 2.2 Job Object
5.2.2 Operations
Conforming Printer implementations SHALL implement all of the
MANDATORY model operations, including mandatory responses, as defined
in this specification in the indicated sections:
For a Printer object:
Print-Job (section 3.2.1) MANDATORY
Print-URI (section 3.2.2) OPTIONAL
Validate-Job (section 3.2.3) MANDATORY
Create-Job (section 3.2.4) OPTIONAL
Get-Attributes (section 3.2.5) MANDATORY
Get-Jobs (section 3.2.6) MANDATORY
For a Job object:
Send-Document (section 3.3.1) OPTIONAL
Send-URI (section 3.3.2) OPTIONAL
Cancel-Job (section 3.3.3) MANDATORY
Get-Attributes (section 3.3.4) MANDATORY
Conforming Printer implementations SHALL support all operation
attributes and all values of such attributes, except for attributes
that are collections of attributes. The following section on
attributes specifies the support required for attributes.
5.2.3 Attributes
Conforming Printer implementations SHALL support all of the MANDATORY
attributes, as defined in this specification in the indicated
sections.
If a Printer supports an attribute, it SHALL support only those values
specified in this document or through the extension mechanism
described in the next section. It MAY support any non-empty subset of
these values. That is, it SHALL support at least one of the specified
values and at most all of them.
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5.2.4 Printer extensions
A conforming Printer may support registered extensions and private
extensions, as long as they meet the requirements specified in Section
6.
A conforming Printer SHALL send responses that conform to the protocol
defined in _Internet Printing Protocol/1.0: Protocol Specification_
[IPP-PRO]. For each attribute included in an operation response, a
conforming printer SHALL send a value whose type and value syntax
conforms to the requirement of this document
5.2.5 Attribute Syntaxes
A Printer SHALL 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. Furthermore, a Printer SHALL
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.
5.3 Security Conformance Requirements
All clients and IPP objects SHALL support the two authentication
mechanisms for HTTP/1.1 as defined in RFC 2068 [RFC2068] and RFC 2069
[RFC2069].
Clients and IPP objects that need mutual authentication and/or
encryption SHOULD also support a secure connection protocol. For this
purpose it is the intention to define standardization of IPP in
combination with Transport Layer Security (TLS), when the TLS
specifications are agreed and on the IETF standards track.
For a detailed discussion of security considerations, see section 8.
6. IANA Considerations (registered and private extensions)
During the development of this standard, the IPP working group
(working with IANA) will register additional keywords and enums while
the standard is in the proposed and draft states according to the
procedures described in this section. IANA will handle registration
of additional enums after this standard is approved in cooperation
with an IANA-appointed registration editor from the IPP working group
according to the procedures described in this section.
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6.1 Typed Extensions
This document uses prefixes to the "keyword" and "enum" basic syntax
type in order to communicate extra information to the reader through
its name. This extra information need not be represented in an
implementation because it is unimportant to a client or Printer. The
list below describes the prefixes and their meaning.
"type1": The IPP standard must be revised to add a new keyword or
a new enum. No private keywords or enums are allowed.
"type2": Implementers can, at any time, add new keyword or enum
values by proposing the specification to the IPP working group
for registration (or an IANA-appointed registry advisor after the
IPP working group is no longer certified) where they are reviewed
for approval. IANA keeps the registry and assigned the number
for enum values
"type3": Implementers can, at any time, add new keyword and enum
values by submitting the complete specification directly to IANA,
no IPP working group or IANA-appointed registry advisor review is
required. IANA keeps the registry and assigned the number for
enum values
"type4": Anyone (system administrators, system integrators, site
managers, etc.) can, at any time, add new installation-defined
values (keywords or new enum values) to a local system. Care
SHOULD be taken by the implementers to see that keywords do not
conflict with other keywords defined by the standard or as
defined by the implementing product. There is no registration or
approval procedure for type 4 keywords.
By definition, each of the four types above assert some sort of
registry or review process in order for extensions to be considered
valid. Each higher level (1, 2, 3, 4) 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 type4 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 specification defines keyword and enum values for all of the
above types, including type4 keywords.
For private (unregistered) keyword extensions, implementers SHOULD use
keywords with a suitable distinguishing prefix, such as "xxx-" where
xxx is the (lowercase) fully qualified company name registered with
IANA for use in domain names [RFC1035].
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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 private (unregistered) enum extension, implementers SHOULD use
values in the reserved integer range which is 2**30 to 2**31-1.
6.2 Registration of MIME types/sub-types for document-formats
The "document-format" attribute's syntax is "mimeType". This means
that valid values are Internet media types. RFC 2045 [RFC2045]
defines the syntax for valid Internet media types. Also, IANA is the
registry for all Internet media types.
6.3 Attribute Extensibility
Attribute names are considered to be set of type2 keywords.
Therefore, new attributes may be registered and have the same status
as attributes in this document by following the type2 extension rules.
6.4 Attribute Syntax Extensibility
Attribute syntaxes are considered to be set of 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.
7. Internationalization Considerations
Some of the attributes have values that are text strings and names
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 SHALL identify 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 Printer object in operation responses
and notifications as described in Section 3.1.3.1. In addition, the
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client MAY separately and individually identify the "exception"
natural language of a supplied 'text' or 'name' attribute using the
technique described for the 'text' attribute syntax in Section 4.1.1.
The Printer object SHALL support the UTF-8 [RFC2044] charset in all
'text' and 'name' attributes supported. If the Printer object
supports more than the UTF-8 charset, the Printer object SHALL convert
between them in order to return the requested charset to the client
according to Section 3.1.3.2. If the Printer object supports more
than one natural language, the Printer object SHOULD return 'text' and
'name' values in the natural language requested for those that are
generated by the Printer (see Section 3.1.3.1).
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 SHALL be returned in the charset requested by the client.
However, the Get-Jobs operation provides for a mechanism to identify
the differing natural languages with each job returned.
The Printer object also has a configured charset and natural language
attribute that it uses when the requested charset or natural language
are not supported. 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 "printer-charset", "charset-supported", "printer-natural-
language", and "natural-language-supported" Printer description
attributes.
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:
Operation Attributes:
job-name (name)
document-name (name)
Job Attributes:
job-name (name)
job-originating-user (name)
job-state-message (text)
job-message-from-operator (text)
Printer Attributes:
printer-name (name)
printer-location (text)
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printer-info (text)
printer-make-and-model (text)
printer-state-message (text)
printer-message-from-operator (text)
8. Security Considerations
It is required that the IPP be able to operate within a secure
environment. IPP attempts to make use of existing security protocols
and services, wherever possible. Examples of such services include the
Digest Access Authentication in HTTP 1.1 [RFC2069] and the Transport
Layer Security (TLS) services, currently under development in the
IETF.
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 use of the protocol to the next. Printing payroll checks, for
example, would have a different value than printing public information
from a file. In addition, there is always the threat of a virus
attack. However, there are no known viruses or potential for viruses
that are self-propagated throughout distributed printing environments.
Therefore, IPP implementations may choose to implement protection
against printer-damaging print jobs.
Since the security levels or the specific threats that any given IPP
print 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.
The initial security needs of IPP are derived from two primary
considerations:
- First, the printing environments envisioned for IPP include
configurations where the client, the Printer, and the document(s)
to be printed may all exist in different security domains. When
objects are in different security domains the requirements for
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authentication and message protection are much stronger than when
they are in the same domain.
- Second, the sensitivity and value of the content being printed
will vary. For example, a publicly available document does not
require the same level of privacy that a payroll document
requires. There are at least two parties that have an interest in
the value of the information being printed, the person asking to
have the information printed and the person who originated the
information. This brings into the picture the need to worry about
copyrights and protection of the content.
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 Client and Printer 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.
8.2 Client and Printer 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 partner's
printer. This latter operation is functionally equivalent to sending
the document to the business partner 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 code.
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8.3 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. If the
client physically gets the document before it prints it, then this
defaults to one of the previous cases.
8.3.1 Unprotected Documents
In many cases, documents to be printed are literally available to
anyone. Documents, such as this Internet Draft which are stored on
anonymous FTP sites, are good examples of this. No security mechanisms
are required to protect access to these documents.
8.3.2 Protected Documents
Clearly, there are cases where the nature of a document requires that
access to it be protected by some authentication and/or authorization
mechanism, or where the right to print the document must be paid for.
This would be the case for sensitive or confidential information, or
where documents are copyrighted or sold for profit. Unauthorized
access to content is a major concern in this environment. Protection
against eavesdropping, document tampering and unauthorized access to
the document are also concerns if the content is sensitive.
8.4 Common Security Scenarios
As discussed earlier, we cannot anticipate the security levels or the
specific threats that any given IPP print administrator may be
concerned with. Security policies might vary from very strong, to
very weak, to none at all. In this section we will describe what we
believe to be four common usage scenarios.
1) No security at all
2) Message protection during transmission
3) Client authentication and authorization
4) Mutual authentication, authorization, and message protection
8.4.1 No Security
If the server requires no authorization and the client wants no
message protection the client can send the print job, i.e., the job
content and the job attributes without invoking any security
mechanisms. The printer will print the job for the client. Print by
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reference also works well in this environment as long as no security
mechanisms are required to access the documents to be printed.
8.4.2 Message Protection During Transmission
There are two types of security that could be used to provide message
protection. These are channel security and object security. In the
first case, the channel can be made secure using the Transport Layer
Security (TLS) protocol, currently under development in the IETF. In
the case of object security, each object is encrypted and sent over
either a secure or insecure channel. The recipient has the
corresponding key to decrypt the object and get the content. Several
object security mechanisms are currently under study in the IETF. IPP
neither mandates the use of these object security mechanisms nor does
it prohibit the use of them. IPP will define a recommended mechanism
for channel security, which is deemed more suitable to meet the IPP
requirements.
8.4.3 Client Authentication and Authorization
This scenario requires client authentication. The authenticated user
ID may be used for authorization purposes, and may be encrypted by the
lower security layer. TLS supports both one sided and mutual
authentication. IPP does not mandate the use of any specific
authorization mechanism (see section 3.1.5.1).
8.4.4 Mutual Authentication, Authorization and Message Protection
This scenario requires mutual authentication and message protection.
TLS can be used for this security feature in these configurations.
8.5 Recommended Security Mechanisms
IPP requires all IPP clients and Printers to support the
authentication features in HTP 1.1 and intends to mandate TLS for
scenarios requiring channel security, once these specifications have
become stabilized.
IPP implementations should provide a range of security options to meet
the needs of different installations and user populations. Many of
the security services that are enabled at a given site will be done so
by a site administrator. The mechanisms used to establish these
services and to define user IDs and passwords to the system are
implementation defined and outside the scope of IPP.
The security protocol used by a particular IPP operation will depend
upon the security services implemented on the Printer, the security
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policy established by a site administrator, and the selection made by
the client. This requires that the right handshake messages be passed
to invoke the selected security service. These are described in the
references for each security mechanism and are normally invoked by the
client. The "security-mechanisms-supported" and "printer-more-info"
attributes can be queried to help the end user know what to expect in
terms of security. These attributes should also appear in the
directory entry for each Printer.
Note: When utilizing HTTP/1.1 as a transport for IPP [IPP-PRO], the
security considerations outlined in HTTP/1.1 apply. When set by an
administrator, IPP servers MUST generate a 401 (Unauthorized) response
code to request client authentication and IPP clients should correctly
respond with the proper Authorization header. Both basic
authentication and digest authentication flavors of authentication
should be supported. The administrator chooses which type(s) of
authentication to accept. Digest authentication is a more secure
method and is always preferred to basic authentication.
For secure communication (privacy in particular), IPP should be run
using a secure communications channel. TLS provides secure
communications channels and provides for mutual authentication. The
secure communications channel must be initiated prior to running the
IPP protocol. There is no mechanism for bootstrapping a secure
communication channel from within the IPP protocol itself.
It is possible to combine a secure communication channel with either
Basic or Digest Authentication.
For a Printer object that supports only non-secure access, the Printer
object supports only the "printer-uri" attribute. For a Printer
object that supports only secure access, the Printer object supports
only the "printer-tls-uri". For a Printer object that supports both
secure and non-secure access, the Printer object supports both the
"printer-uri" and the "printer-tls-uri" attributes.
9. References
[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.
[CS-POL]
H. Alvestrand, "IETF Policy on Character Sets and Languages, work
in progress <draft-alvestrand-charset-policy-01.txt>, August 29,
1997.
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[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-CS]
IANA Registry of Coded Character Sets: ftp://ftp.isi.edu/in-
notes/iana/assignments/character-sets
[IANA-CSa]
N. Freed, J. Postel: IANA CharSet Registration Procedures, Work
in Progress (draft-freed-charset-reg-02.txt).
[IANA-MT]
IANA Registry of Media Types: ftp://ftp.isi.edu/in-
notes/iana/assignments/media-types/
[IPP-PRO]
Herriot, R. (et al), " Internet Printing Protocol/1.0: Protocol
Specifications", draft-ipp-pro-03.txt, November, 1997.
[IPP-RAT]
Zilles, S., "Rationale for the Structure and Model and Protocol
for the Internet Printing Protocol", draft-ipp-rat-01.txt,
November, 1997.
[IPP-REQ]
Wright, D., "Requirements for an Internet Printing Protocol",
draft-ipp-req-01.txt, November, 1997.
[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.
[ISODPA]
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
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[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.
[RFC1035]
P. Mockapetris, "DOMAIN NAMES - IMPLEMENTATION AND
SPECIFICATION", RFC 1035, November 1987.
[RFC1179]
McLaughlin, L. III, (editor), "Line Printer Daemon Protocol" RFC
1179, August 1990.
[RFC1514]
?, " ", RFC 1514, ?.
[RFC1521]
Borenstein, N., and Freed, N., "MIME (Multi-purpose Internet Mail
Extensions) Part One: Mechanism for Specifying and Describing the
Format of Internet Message Bodies", RFC 1521, September, 1993.
[RFC1630]
T. Berners-Lee, "Universal Resource Identifiers in WWW: A
Unifying Syntax for the Expression of Names and Addresses of
Objects on the Network as used in the World-Wide Web", RFC 1630,
June 1994.
[RFC1738]
Berners-Lee, T., Masinter, L., McCahill, M. , "Uniform Resource
Locators (URL)", RFC 1738, December, 1994.
[RFC1759]
Smith, R., Wright, F., Hastings, T., Zilles, S., and Gyllenskog,
J., "Printer MIB", RFC 1759, March 1995.
[RFC1766]
H. Alvestrand, " Tags for the Identification of Languages", RFC
1766, March 1995.
[RFC1808]
?, " ", RFC 1808, ?.
[RFC1825]
R. Atkinson, "Security Architecture for the Internet Protocol",
RFC 1825, August 1995
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[RFC1903]
?, " ", RFC 1903, ?.
[RFC2044]
F. Yergeau, "UTF-8, a transformation format of Unicode and ISO
10646", RFC 2044, October 1996.
[RFC2068]
R. Fielding, J. Gettys, J. Mogul, H. Frystyk, T. Berners-Lee,
"Hypertext Transfer Protocol - HTTP/1.1", RFC 2068, January 1997
[RFC2069]
J. Franks, P. Hallam-Baker, J. Hostetler, P. Leach, A. Luotonen,
E. Sink, L. Stewart, "An Extension to HTTP: Digest Access
Authentication", RFC-2069, Jan 1997.
[RFC2119]
S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119 , March 1997
[RFC2130]
?, " ", RFC 2130, ?.
[RFC2045]
N. Fried, N. Borenstein, ", Multipurpose Internet Mail Extensions
(MIME) Part One: Format of Internet Message Bodies " RFC 2045,
November 1996.
[RFC2046]
Multipurpose Internet Mail Extensions (MIME) Part Two: Media
Types. N. Freed & N. Borenstein. November 1996. (Obsoletes
RFC1521, RFC1522, RFC1590), RFC 2046.
[RFC2048]
Multipurpose Internet Mail Extension (MIME) Part Four:
Registration Procedures. N. Freed, J. Klensin & J. Postel.
November 1996. (Format: TXT=45033 bytes) (Obsoletes RFC1521,
RFC1522, RFC1590) (Also BCP0013), RFC 2048.
[RFC2184]
N. Fried, K. Moore, "MIME Parameter Value and Encoded Word
Extensions: Character Sets, Languages, and Continuations", RFC
2184, August 1997
[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
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10. Copyright Notice
Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be followed,
or as required to translate it into languages other than English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN
WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
11. Author's Address
Scott A. Isaacson (Editor)
Novell, Inc.
122 E 1700 S
Provo, UT 84606
Phone: 801-861-7366
Fax: 801-861-4025
EMail: scott_isaacson@novell.com
Tom Hastings
Xerox Corporation
701 S. Aviation Blvd.
El Segundo, CA 90245
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Phone: 310-333-6413
Fax: 310-333-5514
EMail: hastings@cp10.es.xerox.com
Robert Herriot
Sun Microsystems Inc.
901 San Antonio.Road, MPK-17
Palo Alto, CA 94303
Phone: 415-786-8995 (Area code change to 650 in August 1997)
Fax: 415-786-7077 (Area code change to 650 in August 1997)
Email: robert.herriot@eng.sun.com
Roger deBry
HUC/003G
IBM Corporation
P.O. Box 1900
Boulder, CO 80301-9191
Phone: (303) 924-4080
Fax: (303) 924-9889
Email: debry@vnet.ibm.com
Patrick Powell
San Diego State University
9475 Chesapeake Dr., Suite D
San Diego, CA 95123
Phone: (619) 874-6543
Fax: (619) 279-8424
Email: papowell@sdsu.edu
IPP Mailing List: ipp@pwg.org
IPP Mailing List Subscription: ipp-request@pwg.org
IPP Web Page: http://www.pwg.org/ipp/
Other Participants:
Chuck Adams - Tektronix
Jeff Barnett - IBM
Ron Bergman - Dataproducts Corp.
Sylvan Butler, HP
Keith Carter, IBM Corporation
Jeff Copeland - QMS
Andy Davidson - Tektronix
Mabry Dozier - QMS
Lee Farrell - Canon Information Systems
Steve Gebert - IBM
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Babek Jahromi, Microsoft
David Kellerman - Northlake Software
Rick Landau - Digital
Harry Lewis - IBM
Pete Loya - HP
Ray Lutz - Cognisys Mike MacKay, Novell, Inc.
Carl-Uno Manros, Xerox, Corp.
Jay Martin - Underscore
Stan McConnell - Xerox
Ira McDonald, High North Inc. Paul Moore, Microsoft
Pat Nogay - IBM
Bob Pentecost - HP
Rob Rhoads - Intel
David Roach - Unisys
Stuart Rowley, Kyocera
Hiroyuki Sato - Canon
Bob Setterbo - Adobe
Devon Taylor, Novell, Inc.
Mike Timperman - Lexmark
Randy Turner - Sharp
Atsushi Yuki - Kyocera
Lloyd Young - Lexmark
Bill Wagner - DPI
Jim Walker - DAZEL
Chris Wellens - Interworking Labs
Rob Whittle - Novell
Don Wright - Lexmark
Peter Zehler, Xerox, Corp.
Steve Zilles, Adobe
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12. APPENDIX A: Terminology
This specification uses the terminology defined in this section.
12.1 Conformance Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. The
sections below reiterate these definitions and include some additional
ones.
12.1.1 MUST
This word, or the terms "REQUIRED", "SHALL" or "MANDATORY", means
that the definition is an absolute requirement of the specification.
12.1.2 MUST NOT
This phrase, or the phrase "SHALL NOT", means that the definition is
an absolute prohibition of the specification.
12.1.3 SHOULD
This word, or the adjective "RECOMMENDED", means that there may exist
valid reasons in particular circumstances to ignore a particular item,
but the full implications must be understood and carefully weighed
before choosing a different course.
12.1.4 SHOULD NOT
This phrase, or the phrase "NOT RECOMMENDED" means that there may
exist valid reasons in particular circumstances when the particular
behavior is acceptable or even useful, but the full implications
should be understood and the case carefully weighed before
implementing any behavior described with this label.
12.1.5 MAY
This word, or the adjective "OPTIONAL", means that an item is truly
optional. One vendor may choose to include the item because a
particular marketplace requires it or because the vendor feels that it
enhances the product while another vendor may omit the same item. An
implementation which does not include a particular option MUST be
prepared to interoperate with another implementation which does
include the option, though perhaps with reduced functionality. In the
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same vein an implementation which does include a particular option
MUST be prepared to interoperate with another implementation which
does not include the option (except, of course, for the feature the
option provides.)
12.1.6 NEED NOT
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. Attribute names, some attribute
values, attribute syntaxes, and attribute group names are represented
as keywords. In this document, a keyword is a sequence of characters
(length of 1 to 255) which consists of the following ASCII characters:
lower-case letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"),
period ("."), and underscore ("_"). A keyword starts with a lower-
case letter.
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 an attribute value(s). Each attribute has a specific syntax. All
attributes are defined in section 4.
Job Template Attributes 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.
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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 protocol specification document [IPP-PRO] 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
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 supports Job Template attribute "foo" then it supports both a
"foo-default" default value attribute and a "foo-supported" supported
values attribute. If the Printer object's "foo-supported" attribute
is not populated with some value (even if that value is a legal value
for that attribute), then that Printer object does not support that
value.
A conforming implementation SHALL support all MANDATORY attributes.
However, even for MANDATORY 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-
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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. If a
Printer is not physically capable of stapling, the "finishings-
supported" attribute MUST NOT be populated with the value of 'staple'.
If a Printer is physically capable of stapling, an implementation MAY
choose to support the "finishings-supported" attribute and the value
of 'staple'. Doing so, would enable end users to be aware of and make
use of the stapling feature. 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 within the document data itself. 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.
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
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 IPP. 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 flow back to the end user through the IPP protocol.
Also, since a Printer object may represent a logical print device (not
just a physical devices) 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
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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 an system administrator that desire to control all print jobs
so that no cover 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 (depending on the value of "ipp-attribute-fidelity" of
course). To force the use of banner pages 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 (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 imposed page
An "imposed page" is a page created by placing N print-stream pages
onto a single media page.
13. APPENDIX B: Status Codes
This section defines status code keywords that are used to provide
semantic information on the results of an operation request. Each
operation response MUST include a status code. For error type status
codes, 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.
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
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"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 server failed to fulfill an apparently valid
request
Since IPP status codes are type2 enums, they are extensible. IPP
applications are NOT REQUIRED to understand the meaning of all
registered status codes, though such understanding is obviously
desirable. However, applications SHALL 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 shall not be cached.
For example, if an unrecognized status code of "client-error-foo-bar"
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.
13.1 Status Codes
Each status code is described below. Section 13.2 contains a table
that indicates which status codes apply to which operations.
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 1.0 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.
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13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001)
The request has succeeded, but since ignoring or substituting of
values was requested ("ipp-attribute-fidelity" set to 'false' in the
create request), some attributes were ignored or unsupported values
were substituted with supported values in order to process the job
without rejecting it.
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 1.0 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 server 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 server due to malformed
syntax. The IPP application SHOULD NOT repeat the request without
modifications.
13.1.4.2 client-error-forbidden (0x0401)
The server 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 server 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.
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This status codes reveals more information than "client-error-
forbidden" and "client-error-not-authenticated".
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 server 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 server
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. The server might have been forced to
clean up resources that had been held for the waiting additional
Documents. The server 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 server 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
however 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.
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13.1.4.8 client-error-gone (0x0407)
The requested object is no longer available at the server 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 server 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 web
maintenance by notifying the recipient that the resource is
intentionally unavailable and that the server owners desire 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 server
owner.
13.1.4.9 client-error-request-entity-too-large (0x0408)
The server is refusing to process a request because the request entity
is larger than the server 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 server capacity.
13.1.4.10 client-error-request-URI-too-long (0x0409)
The server is refusing to service the request because the request URI
is longer than the server is willing to interpret. 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
server is under attack by a client attempting to exploit security
holes present in some servers using fixed-length buffers for reading
or manipulating the Request-URI.
13.1.4.11 client-error-unsupported-document-format (0x040A)
The server is refusing to service the request because the document
data is in a format, as specified in the "document-format" input
attribute, that is not supported by the Printer object.
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13.1.4.12 client-error-attribute-not-supported (0x040B)
For a Create-Job, Print-Job or Validate-Job operation, if the IPP
Printer does not support one or more attributes or attribute values
supplied in the request, the Printer shall return this status. For
example, if the request indicates 'iso-a4' media, but that media type
is not supported by the Printer. Or, if the client supplies an
optional attribute and the attribute itself is not even supported by
the Printer. If "ipp-attribute-fidelity" is set to false, the Printer
can ignore or substitute values for unsupported attributes and values
rather than reject the request and return this status code.
For a Get-Jobs operation, if the IPP Printer does not support one of
the requested attributes, the Printer shall return this status.
In practice, an IPP application should avoid this situation by
querying an IPP Printer for its valid attributes and values before
performing an operation on the Printer.
13.1.4.13 client-error-uri-scheme-not-supported (0x040C)
The type of the client supplied URI in a Print-URI or a Send-URI
operation is not supported.
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 SHALL reject the operation and return this
status (see Section 3.1.3.1).
13.1.4.15 client-error-natural-language-not-supported (0x040E)
For any operation, if the IPP Printer does not support the natural
language supplied by the client in the "attributes-natural-language"
operation attribute and the implementation has chosen to reject the
operation, the Printer SHALL return this status (see Section 3.1.3.1).
13.1.5 Server Error Status Codes
This class of status codes indicates cases in which the server is
aware that it has erred or is incapable of performing the request.
The server SHOULD include a message containing an explanation of the
error situation, and whether it is a temporary or permanent condition.
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13.1.5.1 server-error-internal- error (0x0500)
The server 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 server does not support the functionality required to fulfill the
request. This is the appropriate response when the server does not
recognize an operation or is not capable of supporting it.
13.1.5.3 server-error-service-unavailable (0x0502)
The server is currently unable to handle the request due to a
temporary overloading or maintenance of the server. 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-internal-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 server does not support, or refuses to support, the IPP protocol
version that was used in the request message. The server is
indicating that it is unable or unwilling to complete the request
using the same version as supplied in the request other than with this
error message. The response should contain a Message describing why
that version is not supported and what other versions are supported by
that server.
A conforming IPP client shall specify the valid version (IPP 1.0)on
each request. A conforming IPP server (IPP 1.0) SHALL NOT return this
status code to a conforming IPP 1.0 client. An IPP server shall
return this status code to a non-conforming IPP client.
13.1.5.5 server-error-device-error (0x0504)
A printer error, such as a paper jam, occurs while the IPP Printer
processes a Print or Send operation. The response contains the true
Job Status (the values of the "job-state" and "job-state-reasons"
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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.
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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-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
attributes
client-error-bad-request 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-forbidden x x x x x x x x x
client-error-not-possible x x x x x x x x x
client-error-not-found x x x x x x x x x
client-error-timeout 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-URI-too-long x x x x x x x x x
client-error-unsupported-document-format x x x x
client-error-attribute-value-not- x x x x
supported
server-error-internal-error x x x x x x x x x
server-error-service-unavailable x x x x x x x x x
server-error-timeout x x x x x x x x x
server-error-HTTP-version-not-supported x x x x x x x x x
server-error-IPP-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
14. APPENDIX C: "media" keyword values
Standard keyword values are taken from several sources.
Standard values are defined (taken from DPA[ISODPA] and the Printer
MIB[RFC1759]):
'default': The default medium for the output device
'iso-a4-white': Specifies the ISO A4 white medium
'iso-a4-colored': Specifies the ISO A4 colored medium
'iso-a4-transparent' Specifies the ISO A4 transparent medium
'iso-a3-white': Specifies the ISO A3 white medium
'iso-a3-colored': Specifies the ISO A3 colored medium
'iso-a5-white': Specifies the ISO A5 white medium
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'iso-a5-colored': Specifies the ISO A5 colored medium
'iso-b4-white': Specifies the ISO B4 white medium
'iso-b4-colored': Specifies the ISO B4 colored medium
'iso-b5-white': Specifies the ISO B5 white medium
'iso-b5-colored': Specifies the ISO B5 colored medium
'jis-b4-white': Specifies the JIS B4 white medium
'jis-b4-colored': Specifies the JIS B4 colored medium
'jis-b5-white': Specifies the JIS B5 white medium
'jis-b5-colored': Specifies the JIS B5 colored medium
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
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'na-10x15-envelope': Specifies the North American 10x15 inch
envelope
The following standard values are defined for the less commonly used
media (white-only):
'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
'iso-a1-white': Specifies the ISO A1 white medium
'iso-a2-white': Specifies the ISO A2 white medium
'iso-a6-white': Specifies the ISO A6 white medium
'iso-a7-white': Specifies the ISO A7 white medium
'iso-a8-white': Specifies the ISO A8 white medium
'iso-a9-white': Specifies the ISO A9 white medium
'iso-10-white': Specifies the ISO A10 white medium
'iso-b0-white': Specifies the ISO B0 white medium
'iso-b1-white': Specifies the ISO B1 white medium
'iso-b2-white': Specifies the ISO B2 white medium
'iso-b3-white': Specifies the ISO B3 white medium
'iso-b6-white': Specifies the ISO B6 white medium
'iso-b7-white': Specifies the ISO B7 white medium
'iso-b8-white': Specifies the ISO B8 white medium
'iso-b9-white': Specifies the ISO B9 white medium
'iso-b10-white': Specifies the ISO B10 white medium
'jis-b0-white': Specifies the JIS B0 white medium
'jis-b1-white': Specifies the JIS B1 white medium
'jis-b2-white': Specifies the JIS B2 white medium
'jis-b3-white': Specifies the JIS B3 white medium
'jis-b6-white': Specifies the JIS B6 white medium
'jis-b7-white': Specifies the JIS B7 white medium
'jis-b8-white': Specifies the JIS B8 white medium
'jis-b9-white': Specifies the JIS B9 white medium
'jis-b10-white': Specifies the JIS B10 white medium
The following standard values are defined for engineering media:
'a': Specifies the engineering A size medium
'b': Specifies the engineering B size medium
'c': Specifies the engineering C size medium
'd': Specifies the engineering D size medium
'e': Specifies the engineering E size medium
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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
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'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
'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
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'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
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 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.
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In the first case the client is indicating to the Printer: "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: "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 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 attribute
that is OPTIONALLY supplied by the client. The value 'true' indicates
that total fidelity to client supplied 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 may ignore them or substitute any supported value
for unsupported values. 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'. Since this is an OPTIONAL attribute, if the client
does not supply a value, 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'). This is possible across all types of implementations, since
there is a broad range of acceptable actions when substituting or
ignoring unsupported attributes and values. Also, even if the client
supplies a value of 'false', a Printer might still reject the Job for
any reason including an unsupported attributes and/or values. In the
other case, where the client requests a value of 'true', it is
expected that the Printer support this type of printing since the
Printer is already indicating functional support corresponding to all
advertised supported attributes and values.
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.
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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
that 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.
This MANDATORY attribute takes on the following values:
- 'attempted': This value indicates that the Printer attempts to
make sure that 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 makes not
attempt to ensure that 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 try to 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
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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 implementation 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.
Note: The "ipp-attribute-fidelity" attribute applies to the Printer's
ability to either accept or reject other unsupported attributes. In
other words, if "ipp-attribute-fidelity" is set to 'true', a Job is
accepted if and only if the client supplied attributes and values are
supported by the Printer. Whether these attributes actually affect
the processing of the Job 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 use the IPP attributes when processing the Job, and hence,
the IPP attributes may fail to affect the Job processing and output in
any manner whatsoever.
15.3 Suggested Operation Processing Algorithm
When a Printer receives a create request, the Printer either accepts
or rejects the request. The Printer accepts the create request and
creates a Job object if it is able to accept all Job Template and
Document attributes in the request. The Printer rejects the request
and does not create a Job object if the Printer rejects any Job
Template or Document attribute in the request. In order to determine
whether or not to accept or reject the request, the Printer SHOULD use
the following algorithm:
1. The implementation checks to see if the operation is supported.
If not, the Printer rejects the request and sets the appropriate
status code in the response.
2. The implementation checks to see if the requested major version
number is supported. If not, the Printer rejects the request and
sets the appropriate status code in the response. Differences in
the minor version number requested versus what is supported is OK
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if a.) the requested version number has the same Major version
number and the minor version number is higher than supported by
the Printer object, and b.) any attributes that are not known to
the recipient of the operation can be ignored (i.e., if the "ipp-
attribute-fidelity" attribute has the value 'false'.)
3. The implementation checks to see if the client supplied an "ipp-
attribute-fidelity" attribute. If the attribute is missing (not
supplied by the client), the Printer assumes that the value is
'false'.
4. The Printer loops through all other attributes, checking to see
if the requested values are supported (e.g., the value of "foo"
in the request is one of the values in the Printer's "foo-
supported" attribute). If the attribute or its value is
unsupported, the Printer flags it as unsupported.
5. Once all attributes have been checked individually, the Printer
checks for any inconsistent values among all the supported
values. For example a Printer might be able to staple and to
print on transparencies, however due to physical stapling
limitations, the Printer might not be able to staple
transparencies. Any inconsistent values are flagged as
unsupported.
6. Once all attributes have been checked and validated, if "ipp-
attribute-fidelity" is set to true and there are any attributes
flagged as unsupported, the Printer rejects the request and
returns all unsupported attributes and values in the response and
sets the appropriate status code.
7. If "ipp-attribute-fidelity" is set to 'false' (or it was not
supplied by the client) and there are any attributes that are
flagged as unsupported, the Printer, chooses to either ignore the
unsupported attributes or change the requested value to some
supported value. If, for some reason, it is not possible for the
implementation to ignore or substitute values and is unable to
"just print the job", the Printer is still able to reject the
request and return all unsupported attributes and values in the
response. In doing so, the Printer sets the appropriate status
code.
8a. If the requested operation is the Validate-Job operation and a
"document-uri" attribute is supplied in the request, then the
"document-uri" is validated as specified in section 3.2.3,
Validate-Job Operation. If the Printer is able to accept the
request and the validation of any "document-uri" succeeded, then
the Printer object returns the status code "successful-ok".
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Otherwise, it returns a set of unsupported attributes and/or the
appropriate error status code. In either case the processing of
the operation is completed and no objects are created.
8b. The operation is a create request. If the Printer is able to
accept the create request (either as is or the "ipp-attribute-
fidelity" attribute is set to 'false' and some of the requested
attributes can be ignored or have their values substituted), then
the Printer creates a new Job object . The Job object is
populated with those Job Template attributes from the create
request that the Printer object can honor. If the "ipp-attribute-
fidelity" attribute is set to 'true', the Job Template attributes
associated with the new Job object are necessarily all the Job
Template attributes in the accepted create request. If the "ipp-
attribute-fidelity" attribute is set to 'false', the Job Template
attributes associated with the new Job object are all the client
supplied Job Template attributes that are not ignored and/or have
no value substitution. Thus, some of the requested Job Template
attributes may not appear in the Job object because the IPP
processor was not able to honor those attributes. The attributes
that were honored are persistently stored with the Job object for
that Job. A Get-Attributes operation on that Job object will
return only those attributes that a persistently stored with the
Job object.
Note: All Job Template attributes that are persistently stored with
the Job object are intended to be "override values"; that is,
they that take precedence over whatever other embedded
instructions might be in the document data itself. However, it
is not possible for all implementations to realize the semantics
of "override". End users may query the Printer's "pdl-override"
attribute to determine if the Printer either attempts or does not
attempt to override document data instructions with IPP
attributes.
9. There are some cases, where a Printer supports a Job Template
attribute and has an associated default value set for that
attribute. In the case where a client does not supply the
corresponding attribute, the Printer does not use its default
values to populate Job attributes when creating the new Job
object; only Job Template attributes actually in the create
request are used to populate the Job object. The Printer's
default values are only used at Job processing time if no other
IPP attribute or instruction embedded in the document data is
present.
Note: If the default values associated with un-requested Job
Template attributes were used to populate the Job object, then
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these values would become "override values" rather than defaults.
If the Printer supports the 'attempted' value of the "pdl-
override" attribute, then these override values could replace
values specified within the document data. This is not the intent
of the default value mechanism. A default value for an attrbute
SHALL be used only if the create request did not specify that
attribute (or it was ignored when allowed by "ipp-attribute-
fidelity" being 'false') and no value was provided within the
content of the document data.
10. If the client does not supply a value for some Job Template
attribute, and the Printer does not support that attribute, as
far as IPP is concerned, the result of processing that Job (with
respect to the missing attribute) is undefined.
11. Once the Job object has been created, the Printer responds back
to the client with a successful response including Job status
attributes that indicate the initial state of the Job ('pending',
'processing', etc.). The Printer uses its own configuration and
implementation specific algorithms for scheduling the Job in the
correct processing order. Once the Printer begins processing the
Job, the Printer changes the Job's state to 'processing'. If the
Printer supports PDL override (the "pdl-override" attribute set
to 'attempted'), the implementation does its best to see that IPP
attributes take precedence over embedded instructions in the
document data.
12. The implementation of the Printer object continues to process
the Job until it can move the Job into the 'completed' state. If
an Cancel-Job operation is received, the implementation
eventually moves the Job into the 'cancelled' state. If the
system encounters errors during processing that do not allow it
to progress the Job into a completed state, the implementation
halts all processing, cleans up any resources, and moves the Job
into the 'aborted' state.
13. Once the Job moves to the 'completed', 'aborted', or 'canceled'
state, it is an implementation decision as to when to destroy the
Job object and release all associated resources. Once the Job
has been destroyed, the Printer would return either the "not-
found" or "gone" status codes for operations directed at that
Job.
Some Printer implementations may support "ipp-attribute-fidelity" set
to 'true' and "pdl-override" set to 'attempted' and yet still not be
able to realize exactly what the client specifies in the create
request. This is due to legacy decisions and assumptions that have
been made about the role of job instructions embedded within the
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document data and external job instructions that accompany the
document data and how to handle conflicts between such instructions.
The inability to be 100% precise about how a given implementation will
behave is also compounded by the fact that the two special attributes,
"ipp-attribute-fidelity" and "pdl-override", apply to the whole job
rather than specific values for each attribute. For example, some
implementations may be able to override almost all Job Template
attributes except for "number-up".
15.4 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",
"number-up", "sides", "media", and "copies". The processing of each
document in a Job Object SHALL follow the algorithm below. This
algorithm is intended only to identify when and how attributes are to
be used in processing document data and any algorithm that
accomplishes the same effect can be used to implement this
specification.
1. Using the "document-format" attribute or some form of 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 goto step 2. Otherwise, the document data
SHALL be formatted. The formatting algorithm is implementation
defined and is not specified by this specification. The
formatting of the document data uses the "orientation" attribute
to determine how the formatted print data is place on a print-
stream page, see section 4.2.15 for the details.
2. The document data is in the form of a print-stream in a known
media type. The "page-range" attribute is used to select, as
specified in section 4.2.14, a sub-sequence of the pages in the
print-stream that are to be processed and images.
3. The input to this step is sequence of print-stream pages. This
step is controlled by the "number-up" attribute. If 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 4.2.8, to create a single imposed page. If a given
Document Object does not have N more print-stream pages, then the
completion of the imposed page is controlled by the "multiple-
document-handling" attribute as described in section 4.2.6; when
the value of this attribute is 'separate-documents-collated-
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copies', the document data from subsequent Document Objects is
used to complete the imposed page.
The size(scaling), position(translation) and rotation of the print-
stream pages on the imposed page is implementation defined. Note
that during this process the print-stream pages may be rendered
to a form suitable for placing on the imposed page; this
rendering is controlled by the values of the "printer-resolution"
and "print-quality" attributes as described in sections 4.2.10
and 4.2.11. In the case N=1, the imposed pages are nearly the
same as the print-stream pages; 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.
4. The collection of imposed pages is placed, in sequence, onto
sides of the print media. This placement is controlled by the
"sides" attribute and the orientation of the page, as described
in section 4.2.9. The orientation of the page is defined by the
orientation of the imposed pages; for example, if "number-up"
equals 2, then, typically, two portrait print-stream pages become
one landscape imposed page. Note that the placement of imposed
pages onto media instances is also controlled by the "multiple-
document-handling" attribute as described in section 4.2.6.
5. 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 4.2.6 and 4.2.13 for the
details.
6. When the correct number of copies are created, the media
instances are finished according to the values of the
"finishings" attribute as described in 4.2.12. Note that
sometimes finishing operations may require manual intervention to
perform the finishing operations on the copies, especially
uncollated copies. This specification 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. IPP
clients can search or browse for entries of type printer. Clients use
the directory service to find entries based on naming, organizational
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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.
The generic schema is a subset of IPP Printer attributes (section
4.4). These attributes are identified as either MANDATORY or OPTIONAL
for the entry itself. This conformance labeling is NOT the same
conformance labeling applied to the attributes of IPP Printers
themselves. MANDATORY attributes MUST be associated with each
directory entry. OPTIONAL attributes SHOULD 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.
In order to bridge between the directory service protocol and IPP, one
of the MANDATORY attributes is the "printer-uri" attribute. The IPP
client addresses an IPP Printer using its URI and so the directory
entry's "printer-uri" becomes the link between the directory entry and
the corresponding IPP Printer.
The following attributes define the generic schema for directory
entries of type printer:
printer-uri MANDATORY Section 4.4.1
printer-tls-uri OPTIONAL Section
printer-name OPTIONAL Section 4.4.2
printer-location OPTIONAL Section 4.4.3
printer-info OPTIONAL Section 4.4.4
printer-more-info OPTIONAL Section 4.4.5
printer-make-and-model OPTIONAL Section 4.4.7
security-mechanisms-supported MANDATORY Section 4.4.23
media-supported OPTIONAL Section 4.2.5
number-up-supported OPTIONAL Section 4.2.6
sides-supported OPTIONAL Section 4.2.7
printer-resolution-supported OPTIONAL Section 4.2.8
print-quality-supported OPTIONAL Section 4.2.9
color-supported OPTIONAL Section 4.4.20
finishings-supported OPTIONAL Section 4.2.10
document-formats-supported OPTAIONL Section 4.2.14
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