INTERNET-DRAFT
draft-ietf-ipp-model-07.txt
R. deBry
IBM Corporation
T. Hastings
Xerox Corporation
R. Herriot
Sun Microsystems
S. Isaacson
Novell, Inc.
P. Powell
San Diego State University
November 7, 1997
Internet Printing Protocol/1.0: Model and Semantics
Copyright (C) The Internet Society (date). All Rights Reserved.
Status of this Memo
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Abstract
This document is one of a set of documents, which together describe
all aspects of a new Internet Printing Protocol (IPP). IPP is an
application level protocol that can be used for distributed printing
using Internet tools and technologies. 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 (IPP/1.0)
focuses 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 (this document)
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
IPP/1.0. Operator and administrator requirements are out of scope for
version 1.0. 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 and
a Job. The Job 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................................................11
2.2 Job Object....................................................12
2.3 Object Relationships..........................................13
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 .........................22
3.1.4 Operation Status Codes and Messages......................23
3.1.5 Security Concerns for IPP Operations.....................23
3.1.5.1 Authenticated Requester Identity ......................23
3.1.5.2 The "requesting-user-name" Operation Attribute ........24
3.1.5.3 Restricted Queries ....................................25
3.1.6 Versions.................................................25
3.1.7 Job Creation Operations..................................26
3.2 Printer Operations............................................28
3.2.1 Print-Job Operation......................................29
3.2.1.1 Print-Job Request .....................................29
3.2.1.2 Print-Job Response ....................................31
3.2.2 Print-URI Operation......................................34
3.2.3 Validate-Job Operation...................................34
3.2.4 Create-Job Operation.....................................35
3.2.5 Get-Attributes Operation (for Printer objects)...........35
3.2.5.1 Get-Attributes Request ................................36
3.2.5.2 Get-Attributes Response ...............................37
3.2.6 Get-Jobs Operation.......................................37
3.2.6.1 Get-Jobs Request ......................................38
3.2.6.2 Get-Jobs Response .....................................39
3.3 Job Operations................................................40
3.3.1 Send-Document Operation..................................41
3.3.1.1 Send-Document Request .................................42
3.3.1.2 Send-Document Response ................................43
3.3.2 Send-URI Operation.......................................43
3.3.3 Cancel Job Operation.....................................44
3.3.3.1 Cancel-Job Request ....................................44
3.3.3.2 Cancel-Job Response ...................................45
3.3.4 Get-Attributes Operation (for Job objects)...............45
3.3.4.1 Get-Attributes Request ................................46
3.3.4.2 Get-Attributes Response ...............................46
4. Object Attributes .............................................47
4.1 Attribute Syntaxes............................................47
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4.1.1 'text'...................................................48
4.1.2 'name'...................................................49
4.1.3 'keyword'................................................50
4.1.4 'enum'...................................................50
4.1.5 'uri'....................................................51
4.1.6 'uriScheme'..............................................51
4.1.7 'charset'................................................52
4.1.8 'naturalLanguage'........................................52
4.1.9 'mimeMediaType'..........................................53
4.1.10 'octetString'............................................54
4.1.11 'boolean'................................................54
4.1.12 'integer'................................................54
4.1.13 'rangeOfInteger'.........................................54
4.1.14 'dateTime'...............................................55
4.1.15 'resolution'.............................................55
4.1.16 '1setOf X'..............................................55
4.2 Job Template Attributes.......................................56
4.2.1 job-priority (integer(1:100))............................59
4.2.2 job-hold-until (type4 keyword | name)....................60
4.2.3 job-sheets (type4 keyword | name)........................61
4.2.4 multiple-document-handling (type2 keyword)...............61
4.2.5 copies (integer(1:MAX))..................................63
4.2.6 finishings (1setOf type2 enum)...........................63
4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX))..............64
4.2.8 sides (type2 keyword)....................................65
4.2.9 number-up (integer(0:MAX))...............................66
4.2.10 orientation (type2 enum).................................67
4.2.11 media (type4 keyword | name).............................67
4.2.12 printer-resolution (resolution)..........................68
4.2.13 print-quality (type2 enum)...............................68
4.2.14 compression (type3 keyword)..............................69
4.2.15 job-k-octets (integer(0:MAX))............................69
4.2.16 job-impressions (integer(0:MAX)).........................70
4.2.17 job-media-sheets (integer(0:MAX))........................70
4.3 Job Description Attributes....................................70
4.3.1 job-uri (uri)............................................73
4.3.2 job-id (integer(1:MAX))..................................73
4.3.3 job-more-info (uri)......................................73
4.3.4 job-name (name)..........................................73
4.3.5 job-originating-user-name (name).........................74
4.3.6 job-state (type1 enum)...................................74
4.3.7 job-state-reasons (1setOf type2 keyword)................77
4.3.8 job-state-message (text).................................79
4.3.9 number-of-documents (integer(0:MAX)).....................80
4.3.10 containing-printer-uri (uri).............................80
4.3.11 output-device-assigned (name)............................80
4.3.12 time-at-creation (integer(0:MAX))........................80
4.3.13 time-at-processing (integer(0:MAX))......................80
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4.3.14 time-at-completed (integer(0:MAX)).......................81
4.3.15 number-of-intervening-jobs (integer(0:MAX))..............81
4.3.16 job-message-from-operator (text).........................81
4.3.17 job-k-octets-processed (integer(0:MAX))..................81
4.3.18 job-impressions-completed (integer(0:MAX))..............82
4.3.19 job-media-sheets-completed (integer(0:MAX))..............82
4.3.20 attributes-charset (charset).............................82
4.3.21 attributes-natural-language (naturalLanguage)............83
4.4 Printer Description Attributes................................83
4.4.1 printer-uri (uri)........................................85
4.4.2 printer-name (name)......................................85
4.4.3 printer-location (text)..................................85
4.4.4 printer-info (text)......................................85
4.4.5 printer-more-info (uri)..................................86
4.4.6 printer-driver-installer (uri)...........................86
4.4.7 printer-make-and-model (text)............................86
4.4.8 printer-more-info-manufacturer (uri).....................86
4.4.9 printer-state (type1 enum)...............................86
4.4.10 printer-state-reasons (1setOf type2 keyword).............88
4.4.11 printer-state-message (text).............................90
4.4.12 operations-supported (1setOf type2 enum).................90
4.4.13 charset (charset)........................................91
4.4.14 charset-supported (1setOf charset).......................91
4.4.15 natural-language (naturalLanguage).......................92
4.4.16 natural-language-supported (1setOf naturalLanguage)......92
4.4.17 document-format (mimeMediaType)..........................93
4.4.18 document format-supported (1setOf mimeMediaType).........93
4.4.19 printer-is-accepting-jobs (boolean)......................93
4.4.20 queued-job-count (integer(0:MAX))........................93
4.4.21 printer-message-from-operator (text).....................93
4.4.22 color-supported (boolean)................................94
4.4.23 reference-uri-schemes-supported (1setOf uriScheme).......94
4.4.24 pdl-override (type2 keyword).............................94
4.4.25 printer-up-time (integer(1:MAX)).........................95
4.4.26 printer-current-time (dateTime)..........................95
4.4.27 multiple-operation-time-out (integer(1:MAX)).............95
5. Conformance ...................................................96
5.1 Client Conformance Requirements...............................96
5.2 IPP Object Conformance Requirements...........................97
5.2.1 Objects..................................................97
5.2.2 Operations...............................................97
5.2.3 IPP Object Attributes....................................97
5.2.4 Extensions...............................................98
5.2.5 Attribute Syntaxes.......................................98
5.3 charset and Natural Language Requirements.....................98
5.4 Security Conformance Requirements.............................99
6. IANA Considerations (registered and private extensions) .......99
6.1 Typed Extensions..............................................99
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6.2 Registration of MIME types/sub-types for document-formats....101
6.3 Attribute Extensibility......................................101
6.4 Attribute Syntax Extensibility...............................101
7. Internationalization Considerations ..........................101
8. Security Considerations ......................................102
8.1 Client and Printer in the Same Security Domain...............104
8.2 Client and Printer in Different Security Domains.............104
8.3 Print by Reference...........................................104
8.3.1 Unprotected Documents...................................104
8.3.2 Protected Documents.....................................105
8.4 Common Security Scenarios....................................105
8.4.1 No Security.............................................105
8.4.2 Message Protection During Transmission..................105
8.4.3 Client Authentication and Authorization.................106
8.4.4 Mutual Authentication, Authorization and Message
Protection.........................................106
8.5 Recommended Security Mechanisms..............................106
9. References ...................................................107
10. Copyright Notice .............................................110
11. Author's Address .............................................110
12. APPENDIX A: Terminology ......................................113
12.1 Conformance Terminology......................................113
12.1.1 MUST....................................................113
12.1.2 MUST NOT................................................113
12.1.3 SHOULD..................................................113
12.1.4 SHOULD NOT..............................................113
12.1.5 MAY.....................................................114
12.1.6 NEED NOT................................................114
12.2 Model Terminology............................................114
12.2.1 Keyword.................................................114
12.2.2 Attributes..............................................114
12.2.2.1 Attribute Name .......................................115
12.2.2.2 Attribute Group Name .................................115
12.2.2.3 Attribute Value ......................................115
12.2.2.4 Attribute Syntax .....................................115
12.2.3 Supports................................................115
12.2.4 print-stream page.......................................117
12.2.5 impression..............................................118
13. APPENDIX B: Status Codes and Suggested Status Code Messages .118
13.1 Status Codes.................................................119
13.1.1 Informational...........................................119
13.1.2 Successful Status Codes.................................119
13.1.2.1 successful-ok (0x0000) ...............................119
13.1.2.2 successful-ok-ignored-or-substituted-
attributes (0x0001) .............................120
13.1.2.3 successful-ok-conflicting-attributes (0x0002) ........120
13.1.3 Redirection Status Codes................................120
13.1.4 Client Error Status Codes...............................120
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13.1.4.1 client-error-bad-request (0x0400) ....................120
13.1.4.2 client-error-forbidden (0x0401) ......................120
13.1.4.3 client-error-not-authenticated (0x0402) ..............121
13.1.4.4 client-error-not-authorized (0x0403) .................121
13.1.4.5 client-error-not-possible (0x0404) ...................121
13.1.4.6 client-error-timeout (0x0405) ........................121
13.1.4.7 client-error-not-found (0x0406) ......................122
13.1.4.8 client-error-gone (0x0407) ...........................122
13.1.4.9 client-error-request-entity-too-large (0x0408) .......122
13.1.4.10 client-error-request-uri-too-long (0x0409) ...........123
13.1.4.11 client-error-document-format-not-supported (0x040A) ..123
13.1.4.12 client-error-attribute-not-supported (0x040B) ........123
13.1.4.13 client-error-uri-scheme-not-supported (0x040C) .......124
13.1.4.14 client-error-charset-not-supported (0x040D) ..........124
13.1.4.15 client-error-conflicting-attributes (0x040E) .........124
13.1.5 Server Error Status Codes...............................124
13.1.5.1 server-error-internal-error (0x0500) .................124
13.1.5.2 server-error-operation-not-supported (0x0501) ........124
13.1.5.3 server-error-service-unavailable (0x0502) ............125
13.1.5.4 server-error-version-not-supported (0x0503) ..........125
13.1.5.5 server-error-device-error (0x0504) ...................125
13.1.5.6 server-error-temporary-error (0x0505) ................126
13.2 Status Codes for IPP Operations..............................127
14. APPENDIX C: "media" keyword values ..........................127
15. APPENDIX D: Processing IPP Attributes ........................132
15.1 Fidelity.....................................................133
15.2 Page Description Language (PDL) Override.....................134
15.3 Suggested Operation Processing Algorithm for Create and
Validate-Job operations.................................136
15.4 Using Job Template Attributes During Document Processing.....141
16. APPENDIX E: Generic Directory Schema .........................143
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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 described in this model document
does not include features, interfaces, and relationships that are
beyond the scope of the first version of IPP (IPP/1.0). IPP/1.0
incorporates many of the relevant ideas and lessons learned from other
specification and development efforts [HTPP] [ISO10175] [LDPA]
[P1387.4] [PSIS] [RFC1179] [SWP].
The IPP/1.0 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 "support" 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/1.0 model),
there are other components of a print service which are not explicitly
defined in the IPP/1.0 model. The following figure illustrates where
IPP/1.0 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 object encapsulates the functions normally associated
with physical output devices along with the spooling, scheduling and
multiple device management functions often associated with a print
server. Printer objects are optionally registered as entries in a
directory where end users find and select them based on some sort of
filtered and context based searching mechanism (see section 16). The
directory is used to store relatively static information about the
Printer, allowing end users to search for and find Printers that match
their search criteria, for example: name, context, printer
capabilities, etc.. The more dynamic information is directly
associated with the Printer object itself (as compared to the entry in
the directory which only represents the Printer object). This more
dynamic 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 running on behalf of end users) the ability to
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query Printer objects and submit and manage print jobs. An IPP server
is just that part of the Printer object that implements the server-
side protocol. The rest of the Printer object implements (or gateways
into) the application semantics of the print service itself. The
Printer objects may be embedded in an output device or may be
implemented on a host on the network that communicates with 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 the print job by using the Job object's
Cancel-Job operation. The notification service(s) are out of scope
for IPP/1.0, but using such a notification service, the end user is
able to register for and receive Printer specific and Job specific
events. An end user can query the status of Printer objects and can
follow the progress of Job objects by polling using the Get-Attributes
and Get-Jobs operations.
2. IPP Objects
The IPP/1.0 model introduces objects of type Printer and Job. Each
type of object models relevant aspects of a real-world entity such as
a real printer or real print job. Each object type is defined as a
set of possible attributes that may be supported by instances of that
object type. For each object (instance), the actual set of supported
attributes and values describe a specific implementation. The
object's attributes and values describe its state, capabilities,
realizable features, job processing functions, and default behaviors
and characteristics. For example, the Printer object type is defined
as a set of attributes that each Printer object potentially supports.
In the same manner, the Job object type is defined as a set of
attributes that are potentially supported by each Job object.
Each attribute included in the set of attributes defining an object
type is labeled as:
- "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.
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2.1 Printer Object
A major component of the IPP/1.0 model is the Printer object. A
Printer object implements the IPP/1.0 protocol. Using the protocol,
end users may query the attributes of the Printer object and submit
print jobs to the Printer object. The actual implementation
components behind the Printer abstraction may take on different forms
and different configurations. However, the model abstraction allows
the details of the configuration of real components to remain opaque
to the end user. Section 3 describes each of the Printer operations
in detail.
The capabilities and state of a Printer object are described by its
attributes. Printer attributes are divided into two groups:
- "job-template" attributes: These attributes describe supported
job processing capabilities and defaults for the Printer object.
(See section 4.2)
- "printer-description" attributes: These attributes describe the
Printer object's identification, state, location, references to
other sources of information about the Printer object, etc. (see
section 4.4)
Since a Printer object is an abstraction of a generic document output
device and print service provider, a Printer object could be used to
represent any real or virtual device with semantics consistent with
the Printer object, such as a fax device, an imager, or even a CD
writer.
Some examples of configurations supporting a Printer object include:
1) An output device, with no spooling capabilities
2) An output device, with a built-in spooler
3) A print server supporting IPP with one or more associated output
devices
3a) The associated output devices 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 Printer object
might or might not be capable of queuing/spooling.
any indicates any network protocol or direct
connect, including IPP
embedded printer:
output device
+---------------+
O +--------+ | ########### |
/|\ | client |------------IPP------------># Printer # |
/ \ +--------+ | # Object # |
| ########### |
+---------------+
hosted printer:
+---------------+
O +--------+ ########### | |
/|\ | client |--IPP--># Printer #-any->| output device |
/ \ +--------+ # Object # | |
########### +---------------+
+---------------+
fan out: | |
+-->| output device |
any/ | |
O +--------+ ########### / +---------------+
/|\ | client |-IPP-># Printer #--*
/ \ +--------+ # Object # \ +---------------+
########### any\ | |
+-->| output device |
| |
+---------------+
2.2 Job Object
A Job object is used to model a print job. A Job can contain one or
more documents. The information required to create a Job object is
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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. Except for "job-name",
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 document data in a format supported by the Printer
object (typically a Page Description Language - PDL), or
- a reference to such a stream of document data
In IPP/1.0, a document is not modeled as an IPP object, therefore it
has no object identifier or associated attributes. All job processing
instructions are modeled as Job object attributes. These attributes
are called Job Template attributes and they apply equally to all
documents within a Job object.
2.3 Object Relationships
IPP objects have relationships that 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
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existing Job object, however it would have new (different) Job object
identifiers (see section 2.4).
A Job object contains one or more documents. If the contained
document is a stream of document data, that stream can be contained in
only one document. However, there can be 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 document 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 be identified by an identifier so that
they can be persistently and unambiguously referenced. The IPP/1.0
model requires that these identifiers be Uniform Resource Identifiers
(URIs) [RFC1630]. Often, the URI is a URL [RFC1738] [RFC1808].
Note: The IPP/1.0 protocol specification [IPP-PRO] defines a mapping
of the IPP/1.0 model and semantics onto HTTP/1.1. Therefore, all
conforming Printer and Job 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/1.0 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.
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,
such as the unique 32-bit positive integer mentioned later in this
paragraph. In other implementations, the Printer object might be a
central clearing-house for validating all Job object creation
requests, 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 by Job URI or by
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numeric Job ID), when the Printer object successfully processes a
create request and creates a 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
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/1.0. 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; the name 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/1.0 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 support operations. An operation consists of a request
and a response. When a client communicates with an IPP object, the
client issues an operation request to the URI for that object.
Operations have attributes that supply information about the operation
itself. These attributes are called operation attributes (as compared
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to object attributes such as Printer object attributes or Job object
attributes). Each request carries along with it any operation
attributes, object attributes, and/or document data required by the
object to perform the operation. Each request requires a response
from the object. Each response indicates success or failure of the
operation with a status code. 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/1.0 protocol specification [IPP-PRO] describes a mapping
and encoding of IPP/1.0 operations onto HTTP/1.1 POST commands. Other
mappings for IPP/1.0 operations to additional transport mechanisms are
possible.
The IPP/1.0 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. The attributes groups are:
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- Operation Attributes: These attributes are passed in the
operation, 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 that processes the
operation. All IPP objects that accept IPP operation requests
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 prepared to handle the client
supplied operation attribute by realizing the corresponding
feature or function. The addition of new operation attributes
(either OPTIONAL or MANDATORY for the client to supply) will
cause a change to the major version number. Because some
operation attributes are MANDATORY for the client to supply,
every request and response MUST contain those operation
attributes.
- Job Template Attributes: These attributes affect the processing
of a job. A client OPTIONALLY supplies Job Template Attributes
in a create request, and the receiving object MUST be prepared to
receive all supported attributes. The Job object can later be
queried to find out what Job Template attributes were originally
requested in the create request, and such attributes are returned
in the response as Job Object Attributes. The Printer object can
be queried about its Job Template attributes to find out what
type of job processing capabilities are supported and/or what the
default job processing behaviors are, though such attributes are
returned in the response as Printer Object Attributes..
- Job Object Attributes: These attributes are returned in response
to a query operation directed at a Job object.
- Printer Object Attributes: These attributes are returned in
response to a query operation directed at a Printer object.
- Unsupported Attributes: In a create request, the client
OPTIONALLY supplies a set of Job Template attributes. If any of
these are unsupported by the Printer object, the Printer object
returns the set of unsupported attributes 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 each
request and response. The model identifies a specific order for each
group in each request or response, but the attributes within each
group may be in any order. It is an operation error for clients to
supply in operation requests and/or IPP objects to returns in
operations responses attribute value(s) that do not match the
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syntax(es) defined for that attribute (see section 3 for operation
attributes and section 4 for IPP object attributes).
Note: Document data included in the operation is not strictly an
attribute, but it is treated as a special attribute group for ordering
purposes. The only operations that support supplying the document
data within an operation request are Print-Job and Send-Document.
There are no operation responses that include document data.
Note: Some operations are MANDATORY for IPP objects to support; the
others are OPTIONAL (see section 5.2.2). Therefore, before using an
OPTIONAL operation, a client SHOULD first use the MANDATORY Get-
Attributes operation to query the Printer's "operations-supported"
attribute in order to determine which OPTIONAL Printer and Job
operations are actually supported. The client SHOULD NOT use an
OPTIONAL operation that is not supported. When an IPP object
receives a request to perform an operation it does not support, it
returns the 'server-error-operation-not-supported' status code (see
section 13.1.5.2). It is non-conformance when an object does not
support a MANDATORY operation.
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 (the "job-uri"
attribute 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
the 32-bit numeric Job ID (the "job-id" attribute assigned by the
Printer object).
If the operation is directed at the Job object directly using the Job
object's URI, the client SHALL NOT include the redundant "job-id"
operation attribute.
Note: In the mapping of IPP/1.0 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
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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 operation
attribute in the request body. In other mappings of IPP operations
onto other transport mechanisms, 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 within the syntax of the URI, then that port
number MUST be used by the client to contact the IPP object.
2. If the protocol scheme for the URI does not allow an explicit
port number specification, then the default port number for the
protocol MUST be used.
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
operation attributes for every IPP request and response. These
attributes are "attributes-charset" and "attributes-natural-language"
which SHALL be stored as Job Description attributes. For the sake of
brevity in this document, these operation attribute descriptions are
not repeated with every operation request and response, but have a
reference back to this section instead.
3.1.3.1 Request Operation Attributes
The client SHALL supply and the Printer object SHALL support the
following MANDATORY operation attributes in every IPP/1.0 operation
request:
"attributes-charset" (charset):
This operation attribute identifies the charset (coded character
set and encoding method) used by any 'text' and 'name' attributes
that the client is supplying in this request. It also identifies
the charset that the Printer object SHALL use (if supported) for
all 'text' and 'name' attributes and status messages that the
Printer object returns in the response to this request. See
Sections 4.1.1 and 4.1.2 for the specification of the 'text' and
'name' attribute syntaxes.
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All IPP objects 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
client supplied charset value, the Printer object SHALL reject
the request and return the 'client-error-charset-not-supported'
status code. The Printer object SHALL indicate the charset(s)
supported as the values of the " charset-supported" Printer
attribute (see Section 4.4.14), so that the client MAY query
which charset(s) are supported.
Note to client implementers: Since IPP objects are only required
to support the 'utf-8' charset, in order to maximize
interoperability with multiple IPP object implementations, a
client may want to supply 'utf-8' in the "attributes-charset"
operation attribute, even though the client is only passing and
able to present a simpler charset, such as US-ASCII or ISO-8859-
1. Then the client will have to filter out (or charset convert)
those characters that are returned in the response that it cannot
present to its user. On the other hand, if both the client and
the IPP objects also support a charset in common besides utf-8,
the client MAY want to use that charset in order to avoid charset
conversion or data loss.
See the 'charset' attribute syntax description in Section 4.1.7
for the syntax and semantic interpretation of the values of this
attribute and for example values.
"attributes-natural-language" (naturalLanguage):
This operation attribute identifies the natural language used by
any 'text' and 'name' attributes that the client is supplying in
this request. This attribute also identifies the natural
language that the Printer object SHOULD use for all 'text' and
'name' attributes and status messages that the Printer object
returns in the response to this request.
There are no MANDATORY natural languages required for the Printer
object to support. However, the Printer object's "natural-
language-supported" attribute SHALL list the natural languages
supported by the Printer object and any contained Job objects, so
that the client MAY query which natural language(s) are
supported.
For any of the attributes for which the Printer object generates
text, i.e., for the "job-state-message", "printer-state-message",
and status messages (see Section 3.1.4), the Printer object SHALL
be able to generate these text strings in any of its supported
natural languages. If the client requests a natural language
that is not supported, the Printer object SHALL return these
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generated messages in the Printer's configured natural language
as specified by the Printer's "natural-language" attribute" (see
Section 4.4.15).
For other 'text' and 'name' attributes supplied by the client,
authentication system, operator, system administrator, or
manufacturer, i.e., for "job-originating-user-name", "printer-
name" (name), "printer-location" (text), "printer-info" (text),
and "printer-make-and-model" (text), the Printer object is only
required to support the configured natural language of the
Printer identified by the Printer object's "natural-language"
attribute, though support of additional natural languages for
these attributes is permitted.
For any 'text' or 'name' attribute in the request that is in a
different natural language than the value supplied in the
"attributes-natural-language", the client SHALL use the Natural
Language Override mechanism (see section 4.1.1 on the 'text'
attribute syntax) on each attribute value supplied.
The IPP object SHALL accept any natural language and any Natural
Language Override, whether the IPP object supports that natural
language or not (and independent of the value of the "ipp-
attribute-fidelity" Operation attribute), i.e., whether the
Printer object's "natural-language-supported" contains the value
supplied by the client in the "attributes-natural-language"
Operation attribute or in a Natural Language Override. In some
cases, the client supplies an attribute with a natural language
that is not supported. In these cases, the IPP object SHALL
remember that natural language for that attribute, and SHALL
indicate that natural language when returning the attribute in
response to a query. For example, the "job-name" attribute is
supplied by the client in a create request, and its value, if
supplied, is used to populate the Job objects "job-name"
attribute. If the client supplies a Job name in an unsupported
natural language, Printer object SHALL accept the create request
and remember the client supplied natural language. There is no
need for the Printer object to reject the create request just
because the client choose to pick some unsupported natural
language for the Job name. Whenever a client queries the "job-
name" attribute, the IPP object returns the attribute and
indicates the natural language of the attribute as a Natural
Language Override if it is different than the natural language of
the other attributes in the response.
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.
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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/1.0 operation
response:
"attributes-charset" (charset):
This operation attribute identifies the charset used by any
'text' and 'name' attributes that the Printer object is returning
in this response. The value in this response 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.
Note: Whether an implementation that supports more than one
charset stores the data in the charset supplied by the client or
code converts to one of the other supported charsets, depends on
implementation. The strategy SHOULD try to minimize loss of
information during code conversion. In any case, responses SHALL
always be in the charset requested. If this is not possible
(i.e., the charset requested is not supported), the request SHALL
be rejected.
"attributes-natural-language" (naturalLanguage):
This operation attribute identifies the natural language used by
any 'text' and 'name' attributes that the IPP object is returning
in this response. Unlike the "attributes-charset" operation
attribute, the IPP object NEED NOT return the same value as that
supplied by the client in the request. The IPP object MAY return
the natural language of the Job object or the Printer's default,
rather than the natural language supplied by the client. For any
'text' or 'name' attribute or status message in the response that
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is in a different natural language than the value returned in the
"attributes-natural-language" operation attribute, the IPP object
SHALL use the Natural Language Override mechanism (see section
4.1.1 on the 'text' attribute syntax) on each attribute value
returned.
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 end user. If a response does include a status message, an
IPP client NEED NOT examine or display the status message, however it
SHOULD do so in some implementation specific manner.
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
0x7FFF. Section 13 describes the status codes, assigns the numeric
values, and suggests a corresponding status message for each status
code.
A client implementation of IPP SHOULD convert status code values into
any localized message that has semantic meaning to the end user. If
the Printer object supports the status message, the Printer object
MUST be able to generate this message in any of the natural languages
identified by the Printer object's "natural-language-supported"
attribute (see the "attributes-natural-language" operation attribute
specified in Section 3.1.3.1). As described in Section 3.1.3.1 for
any returned 'text' attribute, if there is a choice for generating
this message, the Printer object uses the natural language indicated
by the value of the "attributes-natural-language" in the client
request if supported, otherwise the Printer object uses the value in
the Printer object's own "natural-language" attribute.
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
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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 object is created, the identity of the requester from the create
request is persistently stored in the Job object in an internal
implementation-dependent attribute. This attribute can be used to
match the requester's identity of subsequent operations on that Job
object in order to enforce the local authorization policy(ies), if
any. For example, one site's policy might be that only the job owner
is allowed to cancel a job. Another site's policy might be that any
end user is allowed to cancel any job. There are operation status
codes that allow an IPP object to return 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/1.0, and must be established via some
mechanism outside the scope of IPP/1.0.
3.1.5.2 The "requesting-user-name" Operation Attribute
A Printer object SHALL support the MANDATORY "requesting-user-name"
operation attribute that a client SHOULD supply in all operations.
This operation attribute is provided in case (1) there is no security
service being used, (2) the client and Printer object negotiate to no
authorization, or (3) the authentication service does not make
available to the Printer object an authenticated printable
representation of the user's name that is making the request. The
client SHALL obtain the value for this attribute from an environmental
or network login name for the user, rather than allowing the user to
supply any value.
For create requests the Printer object, upon creating a new Job
object, SHALL store the originating user's name in the MANDATORY "job-
originating-user-name" Job Description attribute. The "job-
originating-user-name" attribute is used for presentation only, such
as returning in queries or printing on start sheets, and is not used
for matching the authenticated principal of subsequent operations. If
the Printer object has access to a more authenticated printable
representation of the user's name, the Printer object SHALL store that
value instead of the value supplied by the client in the "requesting-
user-name" operation attribute.
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The Printer object, upon creating a new Job object, SHALL store the
originating user's principal credential in an internal implementation-
dependent Job Description attribute. This attribute is not specified
as part of IPP, since it is not of any interest to clients. However,
the Printer object uses this internal attribute for matching the
authenticated principal id of subsequent operations. If the Printer
object has access to a more authenticated representation of the user's
id, the Printer object SHALL store that value instead of the value
supplied by the client in the "requesting-user-name" operation
attribute. Otherwise, the Printer object SHALL store the value
supplied by the client in the "requesting-user-name" operation
attribute.
3.1.5.3 Restricted Queries
In many of these IPP operations, a client supplies a list of
attributes to be returned in the response. An IPP object may be
configured, for security reasons, not to return all attributes that a
client requests. The job attributes returned MAY depend on whether
the requesting user is the same as the user that submitted the job.
The IPP object MAY even return none of the requested attributes. In
such cases, the status returned is the same as if the object had
returned all requested attributes. The client cannot tell by such a
response whether the requested attribute was present or absent on the
object.
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 IPP object does not
support that version, the object responds with a status code of
'server-error-version-not-supported'.
There is no version negotiation per se. However, if after receiving a
'server-error-version-not-supported' status code from the Printer,
there is nothing that prevents a client from trying again with a
different version number. In order to conform to IPP/1.0, an
implementation MUST support at least version '1.0'.
There is only one notion of version that covers both IPP Model and 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.
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Changes to the major version number indicate structural or syntactic
changes that make it impossible for older version of IPP clients and
Printer objects 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. As an example,
adding the "ipp-attribute-fidelity" attribute (if it had not been part
of version '1.0'), would have required a change to the major version
number. . Items that might affect the changing of the major version
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
- adding new operation attributes
- adding values to existing operation attributes
- adding MANDATORY operations
Changes to the minor version number indicate the addition of new
features, attributes and attribute values that may not be understood
by all IPP objects, but which can be ignored if not understood. Items
that might affect the changing of the minor version number include any
changes to the model objects and attributes but not the protocol
specification itself (except adding attribute syntaxes), such as:
- grouping all extensions not included in a previous version into a
new version
- adding new attribute values
- changing any of the type1 attributes
- adding new object attributes
- adding new attribute syntaxes
- adding OPTIONAL operations
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 object by including the document data in the request
itself.
- The Print-URI Request: A client that wants to submit a print job
with only a single document (where the Printer object "pulls" the
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document data instead of the client "pushing" the data to the
Printer object) uses the Print-URI operation. In this case, the
client includes in the request only a URI reference to the
document data (not the document data itself).
- The Create-Job Request: A client that wants to submit a print job
with multiple documents uses the Create-Job operation. This
operation is followed by an arbitrary number of Send-Document
and/or Send-URI operations (each creating another document for
the newly create Job object). The Send-Document operation
includes the document data in the request (the client "pushes"
the document data to the printer), and the Send-URI operation
includes only a URI reference to the document data in the request
(the Printer "pulls" the document data from the referenced
location). The last Send-Document or Send-URI request for a
given Job object includes a "last-document" operation attribute
set to 'true' indicating that this is the last document.
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
of client supplied attributes and how a Printer object either accepts
or rejects 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
print 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
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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,
- 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 object has already responded
with a successful status code in the response to the create request,
if the Printer object detects an error, the Printer object is unable
to inform the end user of the error with an operation status code.
In this case, the Printer, depending on the error, can set the "job-
state", "job-state-reasons", or "job-state-message" attributes to the
appropriate value(s) so that later queries can report the correct job
status.
Note: Asynchronous notification of events is outside the scope of
IPP/1.0.
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.
Note: In the HTTP/1.1 mapping of IPP/1.0, 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.
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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. See
Section 15 for a suggested processing algorithm for the create
operations and their Operation and Job Template attributes.
3.2.1.1 Print-Job Request
The following groups of attributes are supplied as part of the Print-
Job Request:
Group 1: Operation Attributes
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. The Printer object
SHALL copy these values to the corresponding Job Description
attributes described in sections 4.3.20 and 4.3.21.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"job-name" (name):
This attribute is OPTIONALLY supplied by the client, and it
contains the client supplied Job name. If this attribute is
supplied by the client, its value is used for the "job-name"
attribute of the newly created Job object. The client MAY
automatically include any information that will help the end-user
distinguish amongst his/her jobs, such as the name of the
application program along with information from the document,
such as the document name, document subject, or source file name.
If this attribute is not supplied by the client, the Printer
generates a name to use in the "job-name" attribute of the newly
created Job object (see Section 4.3.4).
"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
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the end user by using a file name or an application generated
name. If this attribute is supplied, its value can be used in a
manner defined by each implementation. Examples include: printed
along with the Job (job start sheet, page adornments, etc.), used
by accounting or resource tracking management tools, or even
stored along with the document as a document level attribute.
IPP/1.0 does not support the concept of document level
attributes.
"document-format" (mimeMediaType) :
The client OPTIONALLY supplies this attribute. The value of this
attribute describes the format of the supplied document data. If
the client does not supply this attribute, the Printer object
assumes that the document data is in the format defined by the
Printer object's "document-format" attribute.
"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, else the Printer object SHALL
reject the Print-Job request. The value 'false' indicates that a
reasonable attempt to print the Job object is acceptable and the
Printer object SHALL accept the Print-job request. 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-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.
Group 2: Job Template Attributes
The client OPTIONALLY supplies a set of Job Template attributes
as defined in section 4.2.
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, the "attributes-charset" and "attributes-natural-language"
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operation attributes, 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 in the
natural language and charset requested (see Section 3.1.3.1) (if
those are supported, otherwise using the Printer object's default
natural language and charset), and
- at job processing time, uses its corresponding default value
attributes for the supported Job Template attributes that were
not supplied by the client as IPP attribute or embedded
instructions in the document data.
3.2.1.2 Print-Job Response
The Printer object 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. If the client supplies unsupported or conflicting
attributes or values, the Printer object SHALL reject or accept
the Print-Job request depending on the whether the client
supplied a 'true' or 'false' value for the "ipp-attribute-
fidelity" operation attribute. See section 15 for a complete
description of the processing algorithm.
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
"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.
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"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.
Group 3: Unsupported Attributes
This is a set of Job Template attributes supplied by the client
(in the request) that are not supported by the Printer object or
that conflict with one another (see section 15).
Unsupported attributes fall into three categories:
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1. The Printer object does not support the named attribute (no
matter what the value), or
2. The Printer object does support the attribute, but does not
support some or all of the particular values supplied by the
client (i.e., the Printer object does not have those values in
the corresponding supported values attribute).
3. The Printer object does support the attributes and values
supplied, but the particular values are in conflict with one
another, because they violate a constraint, such as not being
able to staple transparencies.
In the case of an unsupported attribute name, the Printer object
returns the client-supplied attribute with a substituted special
value of 'unsupported' indicating no support for the attribute
itself.
In the case of a supported attribute with one or more unsupported
values, the Printer object simply returns the client-supplied
attribute with the unsupported values as supplied by the client.
This indicates support for the attribute, but no support for that
particular value. If the client supplies a multi-valued attribute
with more than one value and the Printer object supports the
attribute but only supports a subset of the client supplied
values, the Printer object SHALL return only those values that
are unsupported.
In the case of two (or more) supported attribute values that are
in conflict because they cannot be used, the Printer object SHALL
return all the values that it ignores or substitutes to resolve
the conflict.
In these three cases, the value of the "ipp-attribute-fidelity"
supplied by the client does not affect what the Printer object
returns. The value of "ipp-attribute-fidelity" only affects
whether the Print-Job operation is accepted or rejected. If the
job is accepted, the client may query the job using the Get-
Attributes operation requesting the attributes returned in the
create response to see which attributes were ignored (not stored
on the Job object) and which attributes were stored with other
(substituted) values.
Note: The simplest response consists of the just the MANDATORY Job
Attributes, the MANDATORY "attributes-charset" and "attributes-
natural-language" operation attributes, and a status code of
"successful-ok".
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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. Before returning the response,
the Printer MUST validate that the Printer supports the retrieval
method (e.g., http, ftp, etc.) implied by the URI, and SHOULD check
for valid URI syntax. The Printer NEED NOT follow the reference and
validate the contents of the reference.
If the Printer object supports this operation, it MUST support the
"reference-uri-schemes-supported" attribute (see section 4.4.23).
It is up to the IPP object to interpret the URI and subsequently
"pull" the document from the source referenced by the URI string.
3.2.3 Validate-Job Operation
This operation is similar to the Print-Job operation (section 3.2.1)
except that a client supplies no document data and the Printer
allocates no resources (i.e., it does not create a new Job object).
This operation is used only to verify capabilities of a printer object
against whatever attributes are supplied by the client in the
Validate-Job request. By using the Validate-Job operation a client
can check that the same Print-Job operation will be accepted without
having to send the document data. The Validate-Job operation also
performs the same security negotiation as the Print-Job operation (see
section 8), so that a client can check that the client and Printer
object security requirements can be met before performing a Print-Job
operation.
Note: The Validate-Job operation does not accept a "document-uri"
attribute in order to allow a client to check that the same Print-URI
operation will be accepted, since the client doesn't send the data
with the Print-URI operation. The client SHOULD just issue the Print-
URI request.
The Printer object returns the same status codes, Operation Attributes
(Group 1) and Unsupported Attributes (Group 3) as the Print-Job
operation. However, no Job Object Attributes (Group 2) are returned,
since no Job object is created.
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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 either of the "document-name" or "document-natural-
language" attributes. This operation is followed by one or more Send-
Document or Send-URI operations. In each of those operation requests,
the client OPTIONALLY supplies the "document-name" and "document-
natural-language" attributes for each document in the multi-document
Job object. If a Printer object supports the Create-Job operation, it
MUST also support the Send-Document operation and also MAY support the
Send-URI operation.
3.2.5 Get-Attributes Operation (for Printer objects)
The Get-Attributes operation allows a client to request the values of
the attributes of a Printer or Job object. This section describes the
former and section 3.3.4 describes the latter. In the request, the
client supplies the set of Printer attribute names and/or attribute
group names in which the requester is interested. In the response,
the Printer object returns a corresponding attribute set with the
appropriate attribute values filled in.
For Printer objects, the possible names of attribute groups are:
- 'job-template': 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' and 'all', the client is actually
requesting the "printer-name" attribute twice: once by naming it
explicitly, and once by inclusion in the 'all' group. In such cases,
the Printer object NEED NOT return each attribute only once in the
response even if it is requested multiple times. The client SHOULD
NOT request the same attribute in multiple ways.
It is NOT REQUIRED that a Printer object support all attributes
belonging to a group (since some attributes are OPTIONAL), however, it
is MANDATORY that each Printer object support all group names.
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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.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"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" (mimeMediaType) :
The client OPTIONALLY supplies this attribute. This attribute is
useful for a Printer object to determine the set of supported
attribute values that relate to the requested document format.
The Printer object 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 object to
eliminate the attributes and values that are not supported for a
specific document format. For example, a Printer object might
have multiple interpreters to support both
'application/postscript' (for PostScript) and 'text/plain' (for
text) documents. However, for only one of those interpreters
might the Printer object be able to support "number-up" with
values of '1', '2', and '4'. For the other interpreter it might
be able to only support "number-up" with a value of '1'.
If the client omits this attribute, the Printer object SHOULD
respond as if the attribute had been supplied with a value set to
the Printer object's "document-format" default value attribute
(if supported). It is recommended that the client always supply
a value for "document-format", since the Printer object's
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"document-format" may be 'application/octet-stream', in which
case the returned attributes and values are for the union of the
document formats that the Printer can automatically sense. For
more details, see the description of the 'mimeMediaType'
attribute syntax in section 4.1.9.
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
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 Job
objects belonging to the target Printer object. The client may also
supply a list of Job attribute names and/or attribute group names. A
group of Job object attributes will be returned for each Job object
that is returned.
This operation is similar Get-Attributes for Job object, except that
this Get-Jobs operation returns attributes from possibly more than one
object (see the description of Job attribute group names in section
3.3.4).
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3.2.6.1 Get-Jobs Request
The client submits the Get-Jobs request to a Printer object.
The following groups of attributes are part of the Get-Jobs Request:
Group 1: Operation Attributes
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.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"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 and/or attribute groups names in whose values
the requester is interested. This set of attributes is returned
for each Job object that is returned. The allowed attribute
group names are the same as those defined in the Get-Attributes
operation for Job objects in section 3.3.4. If the client does
not supply this attribute, the Printer SHALL respond as if the
client had supplied this attribute with two values: 'job-uri' and
'job-id'.
"which-jobs" (keyword):
The client OPTIONALLY supplies this attribute. It indicates
which Job objects SHOULD be returned by the Printer object. The
values for this attribute are:
'completed': This includes any Job object whose state is
'completed', 'canceled', or 'aborted'.
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'not-completed': This includes any Job object whose state is
'pending', 'processing', 'processing-stopped', 'pending-
held', 'unknown'.
If the client does not supply this attribute, the Printer object
SHALL respond as if the client had supplied the attribute with a
value of 'not-completed'.
"my-jobs" (boolean):
The client OPTIONALLY supplies this attribute. It indicates
whether all jobs or just the jobs submitted by the requesting
user of this request SHALL be returned by the Printer object.
If the client does not supply this attribute, the Printer object
SHALL respond as if the client had supplied the attribute with a
value of 'false', i.e., all jobs not just my jobs. The means for
authenticating the requesting user and matching the jobs is
described in section 3.1.5.
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. The Printer object ignores (does
not respond with) any requested attribute which is not supported
or which is restricted by the security policy in force, including
whether the requesting user is the user that submitted the job
(job originating user) or not (see section 3.1.5).
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For any job submitted in a different natural language than the
natural language that the Printer object is returning in the
"attributes-natural-language" operation attribute in the Get-Jobs
response, the Printer SHALL indicate the submitted natural
language by returning the Job object's "attributes-natural-
language" as the first Job object attribute, which overrides the
"attributes-natural-language" operation attribute value being
returned by the Printer object. If any returned 'text' or 'name'
attribute includes a Natural Language Override as described in
the 'text' attribute syntax (see Section 4.1.1), the Natural
Language Override overrides the Job object's "attributes-natural-
language" value and/or the "attributes-natural-language"
operation attribute value.
Jobs are returned in the following order:
- If the client requests all 'completed' Jobs (Jobs in the
'completed', 'aborted', or 'canceled' states), then the Jobs are
returned newest to oldest (with respect to actual completion
time)
- If the client requests all '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. Job objects can be identified
with either a single Job URI or a combination of a Printer URI with a
Job ID.
Note: The following rules apply to all Job operation requests mapped
onto HTTP/1.1:
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- 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.
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 operations (Send-Document or Send-
URI operations) that follow can occur over arbitrarily long periods of
time, each Printer object must decide how long to "wait" for the next
send 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
operation. If the Printer object times-out waiting for the next send
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 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 operation received was in fact the
last document (as if the "last-document" flag had been set to
'true'), close the Job object, and proceed to process it (i.e.,
move the Job's state to 'pending').
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3. Assume that the last send operation 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 object, it is possible that the Job object may
already have been processed to the point that some media sheet 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
Target:
Either (1) the "printer-uri" plus "job-id" or (2) the "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.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"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.
"document-format" (mimeMediaType) :
The client OPTIONALLY supplies this attribute. The value of this
attribute describes the format of the supplied document data. If
the client does not supply this attribute, the Printer object
assumes that the document data is in the format defined by the
Printer object's "document-format" attribute.
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"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.
"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.
Group 2: Document Content
The client MUST supply the document data if the "last-document"
flag is set to 'false'. However, since a client might not know
that the previous document sent with a Send-Document 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
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("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
time a Cancel-Job is received, some media sheet pages might 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 (1) the "printer-uri" plus "job-id" or (2) the "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.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"message" (text):
This attribute is OPTIONALLY supplied by the client. It is a
message to the operator. This "message" attribute is not the
same as the "job-message-from-operator" attribute. That
attribute is used to report a message from the operator to the
end user that queries that attribute. This "message" operation
attribute is used to send a message from the client to the
operator along with the operation request. It is an
implementation decision of how or where to display this message
to the operator (if at all).
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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.
If the job is already in the 'completed', 'aborted', or
'canceled' state, or the 'process-to-stop-point' value is set in
the Job's "job-state-reasons" attribute, the Printer object SHALL
reject the request and return the 'client-error-not-possible'
error status code.
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 'canceled'
state. Between the time of the Cancel-Job operation is accepted and
when the job enters the 'canceled' job-state (see section 4.3.6), the
"job-state-reasons" attribute SHOULD contain the ' processing-to-stop-
point ' value which indicates to later queries that although the Job
might still be 'processing', it will eventually end up in the
'canceled' state, not the 'completed' state.
3.3.4 Get-Attributes Operation (for Job objects)
The Get-Attributes operation allows a client to request the values of
attributes of 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 object
rather than a Printer object 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': all of the Job Description attributes
specified in Section 4.3.
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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, 'job-name' and 'job-description', the client is
actually requesting the "job-name" attribute once by naming it
explicitly, and once by inclusion in the 'job-description' group. In
such cases, the Printer object NEED NOT return the attribute only once
in the response even if it is requested multiple times. The client
SHOULD NOT request the same attribute in multiple ways.
It is NOT REQUIRED that a Job object support all attributes belonging
to a group (since some attributes are OPTIONAL), however it is
MANDATORY that each Job object support all group names.
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 (1) the "printer-uri" plus "job-id" or (2) the "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.
Requesting User Name:
The "requesting-user-name" attribute SHOULD be supplied by the
client as described in section 3.1.5.2.
"requested-attributes" (1setOf keyword) :
The client OPTIONALLY supplies this attribute. It is a set of
attribute names and/or attribute group names in whose values the
requester is interested. If the client omits this attribute, the
Printer object 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:
Group 1: Operation Attributes
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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. The "attributes-
natural-language" MAY be the natural language of the Job object,
rather than the one requested.
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 or which is restricted by the
security policy in force, including whether the requesting user
is the user that submitted the job (job originating user) or not
(see section 3.1.5).
4. Object Attributes
This section describes the attributes with their corresponding
attribute syntaxes and values that are part of the IPP model. The
sections below show the objects and their associated attributes which
are included within the scope of this protocol. Many of these
attributes are derived from other relevant specifications:
- Document Printing Application (DPA) [ISO10175]
- RFC 1759 Printer MIB [RFC1759]
Each attribute is uniquely identified in this document using a
"keyword" (see section 12.2.1). The keyword is included in the
section header describing that attribute. In addition, one of the
attribute syntaxes described below is "keyword". Therefore, some
attributes can be defined as having an attribute syntax that is a set
of keywords.
4.1 Attribute Syntaxes
This section defines the basic attribute syntax types that all clients
and IPP objects SHALL be able to accept in responses and accept in
requests, respectively. Each attribute description in sections 3 and
4 includes the name of attribute syntax(es) in the heading (in
parentheses). A conforming implementation of an attribute SHALL
include the semantics of the attribute syntax(es) so identified.
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Section 6 describes how the protocol can be extended with new
attribute syntaxes.
The attribute syntaxes are specified in the following sub-sections,
where the sub-section heading is the keyword name of the attribute
syntax inside the single quotes. In operation requests and responses
each attribute value MUST be represented as one of the attribute
syntaxes specified in the sub-section heading for the attribute or be
one of the "out of band" values. Standard values are:
'unknown': The attribute is supported, but the value is unknown for
some reason.
'unsupported': The attribute is unsupported.
The protocol specification defines mechanisms for allowing passing
"out of band" values.
Most attributes are defined to have a single attribute syntax.
However, a few attributes (e.g., "job-sheet", "media", "job-hold-
until") are defined to have several attribute syntaxes, depending on
the value. These multiple attribute syntaxes are separated by the "|"
character in the sub-section heading to indicate the choice. Since
each value 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.
4.1.1 'text'
The 'text' attribute syntax is a sequence of one or more characters
encoded in a maximum of 4095 octets. The Printer object SHALL support
the UTF-8 charset [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 supply or the Printer object needs to return a
'text' attribute in a different natural language from 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)
or job attribute (see Section 4.3.21), the client or Printer object
SHALL identify the natural language for that attribute. This
mechanism for identifying the natural language of a single attribute
value is called the Natural Language Override mechanism.
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If the attribute is multi-valued (1setOf text), then the Natural
Language Override must be explicitly specified with each attribute
value whose natural language needs to be overriden. Other values in a
multi-valued 'text' attribute in a request or a response revert to the
natural language of the operation attribute or to the "attributes-
natural-language" Job attribute, if present, in the case of a Get-Jobs
response.
In a create request, the Printer object MUST accept and store with the
Job object any natural languages in the "attributes-natural-language"
operation attribute, whether the Printer object supports that natural
language or not. Furthermore, the Printer object MUST accept and
store with each attribute value any Natural Language Override, whether
the Printer object supports that natural language or not. These
requirements are independent of the value of the "ipp-attribute-
fidelity" operation attribute that the client supplies.
Example: If the client supplies the "attributes-natural-language"
operation attribute with the value: 'en' indicating English, but the
value of the "job-name" attribute is in French, the client MUST use
the Natural Language Override mechanism as follows:
'fr': Natural Language Override indicating French
'Rapport Mensuel': the job name in French
See the Protocol document [IPP-PRO] for a detailed example of the
Natural Language Override mechanism.
4.1.2 'name'
The 'name' attribute syntax is the same as 'text', including the
MANDATORY support of UTF-8 and the Natural Language Override
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
Natural Language Override 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 client MUST use Natural
Language Override as follows:
'de': Natural Language Override indicating German
'Farbdrucker': the Printer name in German
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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 Natural Language Override mechanism, since
they SHALL always be US-ASCII and U.S. English.
Keywords are for use in the protocol. A user interface will likely
provide a mapping between protocol keywords and displayable user-
friendly words and phrases which are localized to the natural language
of the user. While the keywords specified in this document MAY be
displayed to users whose natural language is U.S. English, they MAY be
mapped to other U.S. English words for U.S. English users, since the
user interface is outside the scope of this document.
In the definition for each attribute of this syntax type, the full set
of defined keyword values for that attribute are listed.
When a keyword is used to represent an attribute (its name), it MUST
be unique within the full scope of all IPP objects and attributes.
When a keyword is used to represent a value of an attribute, it MUST
be unique just within the scope of that attribute. That is, the same
keyword 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 (MIN) to 2**31 - 1 (MAX). Each value has an
associated 'keyword' name. In the definition for each attribute of
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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.
Enum values are for use in the protocol. A user interface will
provide a mapping between protocol enum values and displayable user-
friendly words and phrases which are localized to the natural language
of the user. While the enum symbols specified in this document MAY be
displayed to users whose natural language is U.S. English, they MAY be
mapped to other U.S. English words for U.S. English users, since the
user interface is outside the scope of this document.
Note: SNMP MIBs use '2' for 'unknown' which corresponds to the IPP out
of band value 'unknown'. Therefore, most attributes of type 'enum'
often start at '3'.
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]. Though RFC
1736 requires that the values be case-insensitive, IPP requires all
lower case to simplify comparing by IPP clients and Printer objects.
Standard values for this syntax type are the following keywords:
'http': for HTTP schemed URIs (e.g., "http://...")
'https': for HTTPS schemed URIs (e.g., https://...)
'ftp': for FTP schemed URIs (e.g., "ftp://...")
'mailto': for SMTP schemed URIs (e.g., "mailto:...")
'file': for file schemed URIs (e.g., "file:...")
A Printer object MAY support any URI scheme that has been registered
with IANA [IANA-MT]
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4.1.7 'charset'
The 'charset' attribute syntax is a standard identifier for a
"charset". A charset is a coded character set and encoding scheme.
Charsets are used for labeling certain document contents and 'text'
and 'name' attribute values. The syntax and semantics of this
attribute syntax are specified in RFC 2046 [RFC2046] and contained in
the IANA character-set Registry [IANA-CS] according to the IANA
procedures [IANA-CSa]. Though RFC 2046 requires that the values be
case-insensitive US-ASCII, IPP requires all lower case to simplify
comparing by IPP clients and Printer objects. When a character-set in
the IANA registry has more than one name (alias), the name labeled as
"(preferred MIME name)", if present, 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 any characters
defined by ISO 10646 [ISO10646-1].
'us-ascii': 7-bit American Standard Code for Information
Interchange (ASCII), ANSI X3.4-1986 [ASCII]. That 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]. That standard defines a coded character set
that is used by Latin languages in the Western Hemisphere and
Western Europe. US-ASCII is a subset charset.
Some attribute descriptions MAY place additional requirements on
charset values that may be used, such as MANDATORY values that MUST be
supported or additional restrictions, such as requiring that the
charset have US-ASCII as a subset charset.
4.1.8 'naturalLanguage'
The 'naturalLanguage' attribute syntax is a standard identifier for a
natural language and optionally a country. The values for this syntax
type are taken from RFC 1766 [RFC1766]. Though RFC 1766 requires that
the values be case-insensitive US-ASCII, IPP requires all lower case
to simplify comparing by IPP clients and Printer objects. Examples
include:
'en': for English
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'en-us': for US English
'fr': for French
'de': for German
4.1.9 'mimeMediaType'
The 'mimeMediaType' attribute syntax is the Internet Media Type
(sometimes called MIME type) as defined by RFC 2046 [RFC2046] and
registered according to the procedures of RFC 2048 [RFC2048] for
identifying a document format. The value MAY include a charset
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 SHALL be capable of auto-
sensing the format of the document data. If the Printer object's
default value attribute "document-format" is set to
'application/octet-stream', the Printer object not only supports auto-
sensing of the document format, but will depend on the result of
applying its auto-sensing when the client does not supply the
"document-format" attribute. If the client supplies a document format
value, the Printer 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 SHALL 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 SHALL use its
auto-sensing mechanism on the client supplied document data
whether auto-sensing is the Printer object's default or not.
Note: Since the auto-sensing algorithm is probabilistic, if the
client requests both auto-sensing ("document-format" set to
'application/octet-stream') and true fidelity ("ipp-attribute-
fidelity" set to 'true'), the Printer object might not be able to
guarantee exactly what the end user intended (the auto-sensing
algorithm might mistake one document format for another ), but it is
able to guarantee that its auto-sensing mechanism be used.
4.1.10 'octetString'
The 'octetString' attribute syntax is a sequence of octets encoded in
a maximum of 4095 octets. This syntax type is used for opaque data.
4.1.11 'boolean'
The 'boolean' attribute syntax is similar to an enum 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 (MIN) to 2**31 - 1 (MAX). 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 pair of integers
that defines an inclusive range of integer values. The first integer
specifies the lower bound and the second specifies the upper bound.
If a range constraint is specified in the header description for an
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attribute in this document whose attribute syntax is 'rangeOfInteger'
(i.e., 'X:Y' indicating X as a minimum value and Y as a maximum
value), then the constraint applies to both integers.
4.1.14 'dateTime'
The 'dateTime' attribute syntax is a standard, fixed length, 11 octet
representation of the "DateAndTime" syntax as defined in RFC 1903
[RFC1903]. RFC 1903 also identifies an 8 octet representation of a
"DateAndTime" value, but IPP objects MUST use the 11 octet
representation. 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
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.
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4.2 Job Template Attributes
Job Template attributes describe job processing behavior. Support for
Job Template attributes by a Printer object is OPTIONAL (see section
12.2.3 for a description of support for OPTIONAL attributes). Also,
clients OPTIONALLY supply Job Template attributes in create requests.
Job Template attributes conform to the following rules. For each Job
Template attribute called "xxx":
1. If the Printer object supports "xxx" then it SHALL support both
a "xxx-default" default value attribute (unless there is a "No"
in the table below) and a "xxx-supported" supported values
attribute.
2. "xxx" is OPTIONALLY supplied by the client in a create request.
If "xxx" is supplied, the client is indicating a desired job
processing behavior for this Job. When "xxx" is not supplied, the
client is indicating that the Printer object apply its default job
processing behavior at job processing time if the document content
does not contain an embedded instruction indicating an xxx-related
behavior.
Note: Since an administrator MAY change the default value
attribute after a Job object has been submitted but before it has
been processed, the default value used by the Printer object at
job processing time may be different that the default value in
effect at job submission time.
The "xxx-supported" attribute is a Printer object attribute that
describes which job processing behaviors are supported by that Printer
object. A client can query the Printer object to find out what xxx-
related behaviors are supported by inspecting the returned values of
the "xxx-supported" attribute. The "xxx-default" default value
attribute describes what will be done at job processing time when no
other job processing information is supplied by the client (either
explicitly as an IPP attribute in the create request or implicitly as
an embedded instruction within the document data).
If an application wishes to present an end user with a list of
supported values from which to choose, the application SHOULD query
the Printer object for its supported value attributes. The
application SHOULD also query the default value attributes. If the
application then limits selectable values to only those value that are
supported, the application can guarantee that the values supplied by
the client in the create request all fall within the set of supported
values at the Printer. When querying the Printer, the client MAY
enumerate each attribute by name in the Get-Attributes Request, or the
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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
Printer will use at job processing time 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, unless
the document(s) contain embedded finishing instructions.
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-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 |
| | name) | type4 keyword | name)|
+-------------------+----------------------+----------------------+
| job-sheets | job-sheets-default |job-sheets-supported |
| (type4 keyword | | (type4 keyword | |(1setOf
| name) | name) | type4 keyword | name)|
+-------------------+----------------------+----------------------+
|multiple-document- |multiple-document- |multiple-document- |
| handling | handling-default |handling-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
+-------------------+----------------------+----------------------+
| copies | copies-default | copies-supported |
| (integer (1:MAX)) | (integer (1:MAX)) | (integer (1:MAX)) |
| | | |
| | copies-collated- | copies-collated- |
| | default | supported |
| | (integer (1:MAX)) | (integer (1:MAX)) |
+-------------------+----------------------+----------------------+
| finishings | finishings-default | finishings-supported |
|(1setOf type2 enum)|(1setOf type2 enum) |(1setOf type2 enum) |
+-------------------+----------------------+----------------------+
| page-ranges | No | page-ranges- |
| (1setOf | | supported (boolean) |
| rangeOfInteger | | |
| (1:MAX)) | | |
+-------------------+----------------------+----------------------+
| sides | sides-default | sides-supported |
| (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)|
+-------------------+----------------------+----------------------+
| number-up | number-up-default | number-up-supported |
| (integer (0:MAX)) | (integer (0:MAX)) |(1setOf integer |
| | | (0:MAX) | |
| | | rangeOfInteger |
| | | (0:MAX)) |
+-------------------+----------------------+----------------------+
| orientation | orientation-default | orientation- |
| (type2 enum) | (type2 enum) | supported |
| | | (1setOf type2 enum) |
+-------------------+----------------------+----------------------+
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| media | media-default | media-supported |
| (type4 keyword | | (type4 keyword | |(1setOf |
| name) | name) | type4 keyword | name)|
| | | |
| | | media-ready |
| | |(1setOf |
| | | type4 keyword | name)|
+-------------------+----------------------+----------------------+
| printer-resolution| printer-resolution- | printer-resolution- |
| (resolution) | default | supported |
| | (resolution) |(1setOf resolution) |
+-------------------+----------------------+----------------------+
| print-quality | print-quality-default| print-quality- |
| (type2 enum) | (type2 enum) | supported |
| | |(1setOf type2 enum) |
+-------------------+----------------------+----------------------+
| compression | No | compression-supported|
| (type3 keyword) | |(1setOf type3 keyword)|
+-------------------+----------------------+----------------------+
| job-k-octets | No |job-k-octets-supported|
| (integer (0:MAX)) | | (rangeOfInteger |
| | | (0:MAX)) |
+-------------------+----------------------+----------------------+
| job- | No | job-impressions- |
| impressions | | supported |
| (integer (0:MAX)) | | (rangeOfInteger |
| | | (0:MAX)) |
+-------------------+----------------------+----------------------+
| job-media- | No | job-media-sheets- |
| sheets | | supported |
| (integer (0:MAX)) | | (rangeOfInteger) |
| | | (0:MAX)) |
+-------------------+----------------------+----------------------+
4.2.1 job-priority (integer(1:100))
This attribute specifies a priority for scheduling the Job. A higher
value specifies a higher priority. The value 1 indicates the lowest
possible priority. The value 100 indicates the highest possible
priority. Among those jobs that are ready to print, a Printer SHALL
print all jobs with a priority value of n before printing those with a
priority value of n-1 for all n.
If the Printer object supports this attribute, it SHALL always support
the full range from 1 to 100. No administrative restrictions are
permitted. This way an end-user can always make full use of the
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entire range with any Printer object. If privileged jobs are
implemented outside IPP/1.0, they SHALL have priorities higher than
100, rather than restricting the range available to end-users.
The syntax for the "job-priority-supported" is also integer(1:100).
This single integer value indicates the number of priority levels
supported. The Printer object SHALL take the value supplied by the
client and map it to the closest integer in a sequence of n integers
values that are evenly distributed over the range from 1 to 100 using
the formula:
roundToNearestInt((100x+50)/n)
where n is the value of "job-priority-supported" and x ranges from 0
through n-1.
For example, if n=1 the sequence of values is 50; if n=2, the
sequence of values is: 25 and 75; if n = 3, the sequence of values
is: 17, 50 and 83; if n = 10, the sequence of values is: 5, 15, 25,
35, 45, 55, 65, 75, 85, and 95; if n = 100, the sequence of values
is: 1, 2, 3, _ 100.
If the value of the Printer object's "job-priority-supported" is 10
and the client supplies values in the range 1 to 10, the Printer
object maps them to 5, 11 to 20, the Printer object maps them to 15,
etc.
4.2.2 job-hold-until (type4 keyword | name)
This 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 (after close of business)
'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
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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 there are no other
job state reasons that keep the job 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 the
specified time period has already started, the job SHALL be a
candidate for processing immediately.
4.2.3 job-sheets (type4 keyword | name)
This attribute determines which job start/end sheet(s), if any, SHALL
be printed with a job.
Standard values are:
'none': no job sheet is printed
'standard': one or more site specific standard job sheets are
printed, e.g. a single start sheet or both start and end sheet is
printed
An administrator MAY define additional values using the 'name' or
'keyword' attribute syntax, depending on implementation.
Note: The effect of this attribute on jobs with multiple documents MAY
be affected by the "multiple-document-handling" job attribute (section
4.2.4), depending on the job sheet semantics.
4.2.4 multiple-document-handling (type2 keyword)
This attribute is relevant only if a job consists of two or more
documents. The attribute controls finishing operations and the
placement of one or more print-stream pages into impressions and onto
media sheets. When the value of the "copies" attribute exceeds 1, it
also controls the order in which the copies that result from
processing the documents are produced. For the purposes of this
explanations, if "a" represents an instance of document data, then the
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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
sequences a(*),b(*). The Printer object SHALL NOT force the data
in each document instance to be formatted onto a new print-stream
page, nor to start a new impression on a new media sheet. If more
than one copy is made, the ordering of the sets of media sheets
resulting from processing the document data SHALL be a(*), b(*),
a(*), b(*), ..., and the Printer object SHALL force each copy
(a(*),b(*)) 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 object SHALL force each copy
of the result of processing the data in a single document to
start on a new media sheet. If more than one copy is made, the
ordering of the sets of media sheets resulting from processing
the document data 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. The Printer object SHALL force each copy of
the result of processing the data in a single document to start
on a new media sheet. If more than one copy is made, the
ordering of the sets of media sheets resulting from processing
the document data SHALL be a(*), b(*), a(*), b(*), ... .
The 'single-document' value is the same as 'separate-documents-
collated-copies' with respect to ordering of print-stream pages, but
not media sheet generation, since 'single-document' will put the first
page of the next document on the back side of a sheet if an odd number
of pages have been produced so far for the job, while 'separate-
documents-collated-copies' always forces the next document or document
copy on to a new sheet. In addition, if the _finishings_ attribute
specifies `staple', then with 'single-document', documents a and b are
stapled together as a single document, but with 'separate-documents-
collated-copies', documents a and b are stapled separately.
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The relationship of this attribute and the other attributes that
control document processing is described in section 15.4.
4.2.5 copies (integer(1:MAX))
This attribute specifies the number of copies to be printed.
On many devices the supported number of collated copies will be
limited by the number of physical output bins on the device, and may
be different from the number of uncollated copies which can be
supported.
The "copies-supported" attribute is the limit on the number of
uncollated copies supported, i.e., the limit when the value of the
"multiple-document-handling" attribute is 'single-document' or
'separate-documents-uncollated-copies'. The " copies-collated-
supported" attribute is the limit on the number of collated copies
supported, i.e., the limit when the value of the "multiple-document-
handling" attribute is 'separate-documents-collated-copies'.
The "copies-default" attribute is the default for the number of
uncollated copies, i.e., the default when the value of the "multiple-
document-handling" attribute is 'single-document' or 'separate-
documents-uncollated-copies'. The " copies-collated-default"
attribute is the default for the number of collated copies, i.e., the
default when the value of the "multiple-document-handling" attribute
is 'separate-documents-collated-copies'.
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.
4.2.6 finishings (1setOf type2 enum)
This attribute identifies the finishing operations that the Printer
uses for each copy of each printed document in the Job. For Jobs with
multiple documents, the "multiple-document-handling" attribute
determines what constitutes a "copy" for purposes of finishing.
Standard values are:
Value Symbolic Name and Description
'3' 'none': Perform no finishing
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'4' 'staple': Bind the document(s) with one or more staples.
The exact number and placement of the staples is site-
defined.
'5' 'punch': This value indicates that holes are required in
the finished document. The exact number and placement
of the holes is site-defined The punch specification
MAY be satisfied (in a site- and implementation-
specific manner) either by drilling/punching, or by
substituting pre-drilled media.
'6' 'cover': This value is specified when it is desired to
select a non-printed (or pre-printed) cover for the
document. This does not supplant the specification of a
printed cover (on cover stock medium) by the document
itself.
'7' 'bind': This value indicates that a binding is to be
applied to the document; the type and placement of the
binding is site-defined."
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.
If the client supplies a value of 'none' along with any other
combination of values, it is the same as if only that other
combination of values had been supplied (that is the 'none' value has
no effect).
4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX))
This attribute identifies the range(s) of print-stream pages that the
Printer object uses for each copy of each document which are to be
printed. Nothing is printed for any pages identified that do not
exist in the document(s).
For Jobs with multiple documents, the "multiple-document-handling"
attribute determines what constitutes a "copy" for purposes of the
specified page range(s). When "multiple-document-handling" is
'single-document', the Printer object SHALL apply each supplied page
range once to the concatenation of the print-stream pages. For
example, if there are 8 documents of 10 pages each, the page-range
'41:60' prints the pages in the 5th and 6th documents as a single
document and none of the pages of the other documents are printed.
When "multiple-document-handling" is 'separate-document-uncollated-
copies' or 'separate-document-collated-copies', the Printer object
SHALL apply each supplied page range repeatedly to each document copy.
For the same job, the page-range '1:3, 10:10' would print the first 3
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pages and the 10th page of each of the 8 documents in the Job, as 8
separate documents.
In most cases, the exact pages to be printed will be generated by a
device driver and this attribute would not be required. However, when
printing an archived document which has already been formatted, the
end user may elect to print just a subset of the pages contained in
the document. In this case, if page-range = n.m is specified, the
first page to be printed will be page n. All subsequent pages of the
document will be printed through and including page m.
"page-ranges-supported" is a boolean value indicating whether or not
the printer is capable of supporting the printing of page ranges.
This capability may differ from one PDL to another. There is no "page-
ranges-default" attribute. If the "page-ranges" attribute is not
supplied by the client, all pages of the document will be printed.
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 sides (type2 keyword)
This attribute specifies how print-stream pages are to be imposed upon
the sides of an instance of a selected medium (an impression).
The standard values are:
'one-sided': imposes each consecutive print-stream page upon the
same side of consecutive media sheets.
'two-sided-long-edge': imposes each consecutive pair of print-
stream pages upon front and back sides of consecutive media
sheets, such that the orientation of each pair of print-stream
pages on the medium would be correct for the reader as if for
binding on the long edge. This imposition is sometimes called
'duplex' or 'head-to-head'.
'two-sided-short-edge': imposes each consecutive pair of print-
stream pages upon front and back sides of consecutive media
sheets, such that the orientation of each pair of print-stream
pages on the medium would be correct for the reader as if for
binding on the short edge. This imposition is sometimes called
'tumble' or 'head-to-toe'.
'two-sided-long-edge', 'two-sided-short-edge', 'tumble', and 'duplex'
all work the same for portrait or landscape. However 'head-to-toe' is
'tumble' in portrait but 'duplex' in landscape. 'head-to-head' also
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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.
4.2.9 number-up (integer(0:MAX))
This attribute specifies the number of print-stream pages to impose
upon a single side of an instance of a selected medium. For example,
if the value is
Value Description
'0' The Printer SHALL place one print-stream page on a single
side of an instance of the selected medium and SHALL
NOT add any sort of translation, scaling, rotation or
other embellishment).
'1' The Printer SHALL place one print-stream page on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
'2' The Printer SHALL place two print-stream pages on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
'4' The Printer SHALL place four print-stream pages on a single
side of an instance of the selected medium (MAY add
some sort of translation, scaling, or rotation).
This attribute primarily controls the translation, scaling and
rotation of print-stream pages, but a site may choose to add
embellishments, such as borders, to any non-zero value.
Note: The '0' value is for the protocol. It is expected that a
client would chose some more user-friendly representation for
displaying the value '0' to the end-user, such as 'none', rather than
displaying a zero.
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.
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4.2.10 orientation (type2 enum)
This attribute specifies the orientation of the content of the print-
stream 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:
Value Symbolic Name and Description
'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 print-stream page to be imaged by +90
degrees with respect to the medium (i.e. anti-
clockwise) from the portrait orientation. Note: The
+90 direction was chosen because simple finishing on
the long edge is the same edge whether portrait or
landscape
'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 print-stream page to be imaged
by -90 degrees with respect to the medium (i.e.
clockwise) from the portrait orientation. Note: The
'reverse-landscape' value was added because some
applications rotate landscape -90 degrees from
portrait, rather than +90 degrees.
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.
4.2.11 media (type4 keyword | name)
This attribute identifies the medium that the Printer uses for all
impressions of the Job.
The values for "media" include medium-names, medium-sizes, input-trays
and electronic forms so that one attribute specifies the media. If a
Printer object supports a medium name as a value of this attribute,
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such a medium name implicitly selects an input-tray that contains the
specified medium. If a Printer object supports a medium size as a
value of this attribute, such a medium size implicitly selects a
medium name that in turn implicitly selects an input-tray that
contains the medium with the specified size. If a Printer object
supports an input-tray as the value of this attribute, such an input-
tray implicitly selects the medium that is in that input-tray at the
time the job prints. This case includes manual-feed input-trays. If
a Printer object supports an electronic form as the value of this
attribute, such an electronic form implicitly selects a medium-name
that in turn implicitly selects an input-tray that contains the medium
specified by the electronic form. The electronic form also implicitly
selects an image that the Printer 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 Printer attribute named "media-ready"
which differs from "media-supported" in that legal values only include
the subset of "media-supported" values that are physically loaded and
ready for printing with no operator intervention required.
The relationship of this attribute and the other attributes that
control document processing is described in section 15.4.
4.2.12 printer-resolution (resolution)
This attribute identifies the resolution that Printer uses for the
Job.
4.2.13 print-quality (type2 enum)
This attribute specifies the print quality that the Printer uses for
the Job.
The standard values are:
Value Symbolic Name and Description
'3' 'draft': lowest quality available on the printer
'4' 'normal': normal or intermediate quality on the printer
'5' 'high': highest quality available on the printer
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4.2.14 compression (type3 keyword)
This attribute identifies compression algorithms used on compressed
document data. The value of this attribute does not apply to 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
4.2.15 job-k-octets (integer(0:MAX))
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.
This value SHALL also not include the multiplicative factor due to a
copies instruction embedded in the document data. If the document
data actually includes replications of the document data, this value
will include such replication. In other words, this value is always
the size of the source document data, rather than a measure of the
hardcopy output to be produced.
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 object may try to
compute the value if it is not supplied in the create request. Even
if the client does supply a value for these three attributes in the
create request, the Printer object MAY choose to change the value if
the Printer object is able to compute a value which is more accurate
than the client supplied value. The Printer object may be able to
determine the correct value for these three attributes either right at
job submission time or at any later point in time. If the value of
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this attribute is unknown at the moment, the Printer object MAY choose
to respond with a special value of 'unknown' rather than not return
the attribute at all.
4.2.16 job-impressions (integer(0:MAX))
This attribute specifies the total number of impressions of the
document(s) being requested by this job to produce.
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.
As with "job-k-octets", this value SHALL also not include the
multiplicative factor due to a copies instruction embedded in the
document data. If the document data actually includes replications of
the document data, this value will include such replication. In other
words, this value is always the number of impressions in the source
document data, rather than a measure of the number of impressions to
be produced.
See the Note in the "job-k-octets" attribute that also applies to this
attribute.
4.2.17 job-media-sheets (integer(0:MAX))
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 contributed by the
number of copies specified by the "copies" attribute and number of
copies instructions embedded in the document data, if any.
See the Note in the "job-k-octets" attribute that also applies to this
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
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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-name | name | MANDATORY |
+----------------------------+----------------------+----------------+
| job-state | type1 enum | MANDATORY |
+----------------------------+----------------------+----------------+
| job-state-reasons | 1setOf type2 keyword | |
+----------------------------+----------------------+----------------+
| job-state-message | text | |
+----------------------------+----------------------+----------------+
| number-of-documents | integer (0-MAX) | |
+----------------------------+----------------------+----------------+
| containing-printer-uri | uri | MANDATORY |
+----------------------------+----------------------+----------------+
| output-device-assigned | name | |
+----------------------------+----------------------+----------------+
| time-at-creation | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| time-at-processing | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| time-at-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| number-of-intervening-jobs | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-message-from-operator | text | |
+----------------------------+----------------------+----------------+
| job-k-octets-processed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-impressions-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| job-media-sheets-completed | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| attributes-charset | charset | MANDATORY |
+----------------------------+----------------------+----------------+
| attributes-natural-language| naturalLanguage | MANDATORY |
+----------------------------+----------------------+----------------+
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4.3.1 job-uri (uri)
This MANDATORY attribute contains the URI for the job. The Printer
object, on receipt of a new job, generates a URI which identifies the
new Job on that Printer object. The Printer object 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 MANDATORY attribute contains the ID of the job. The Printer, on
receipt of a new job, generates an ID which identifies the new Job on
that Printer. The Printer returns the value of the "job-id" attribute
as part of the response to a create request. The 0 value is not used
for compatibility with SNMP index values which cannot be 0.
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 MANDATORY attribute is the name of the job. It is a name that is
more user friendly than the "job-uri" attribute value. It does not
need to be unique between Jobs. The Job's "job-name" attribute is set
to the value supplied by the client in the "job-name" operation
attribute in the create request (see Section 3.2.1.1). If, however,
the "job-name" operation attribute is not supplied by the client in
the create request, the Printer object, on creation of the Job, 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-name" operation attribute of the
first (or only) document, 2) the "document-URI" attribute of the first
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(or only) document, or 3) any other piece of Job specific and/or
Document Content information.
4.3.5 job-originating-user-name (name)
This MANDATORY attribute contains the name of the end user that
submitted the print job. The Printer object sets this attribute to
the most authenticated printable name that it can obtain from the
authentication service over which the IPP operation was received.
Only if such is not available, does the Printer object use the value
supplied by the client in the "requesting-user-name" operation
attribute of the create operation. See Section 3.1.5.
Note: The Printer object needs to keep an internal originating user
id of some form, typically as a credential of a principal, with the
Job object. Since such an internal attribute is implementation-
dependent and not of interest to clients, it is not specified as a Job
Description attribute. This originating user id is used for
authorization checks (if any) on all subsequent operation.
4.3.6 job-state (type1 enum)
This MANDATORY 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:
Values Symbolic Name and Description
'3' 'pending': The job is a candidate to start processing, but
is not yet processing.
'4' 'pending-held': The job is not a candidate for processing
for any number of reasons but will return to the
'pending' state as soon as the reasons are no longer
present. The job's "job-state-reason" attribute SHALL
indicate why the job is no longer a candidate for
processing.
'5' 'processing': One or more of:
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1. the job is using, or is attempting to use, one or
more purely software processes that are analyzing,
creating, or interpreting a PDL, etc.,
2. the job is using, or is attempting to use, one or
more hardware devices that are interpreting a PDL,
making marks on a medium, and/or performing finishing,
such as stapling, etc.,
3. the Printer object has made the job ready for
printing, but the output device is not yet printing it,
either because the job hasn't reached the output device
or because the job is queued in the output device or
some other spooler, awaiting the output device to print
it.
When the job is in the 'processing' state, the entire
job state includes the detailed status represented in
the printer's "printer-state", "printer-state-reasons",
and "printer-state-message" attributes.
Implementations MAY, though they NEED NOT, include
additional values in the job's "job-state-reasons"
attribute to indicate the progress of the job, such as
adding the 'job-printing' value to indicate when the
output device is actually making marks on paper and/or
the 'processing-to-stop-point' value to indicate that
the IPP object is in the process of canceling or
aborting the job. Most implementations won't bother
with this nuance.
'6' 'processing-stopped': The job has stopped while processing
for any number of reasons and will return to the
'processing' state as soon as the reasons are no longer
present.
The job's "job-state-reason" attribute MAY indicate why
the job has stopped processing. For example, if the
output device is stopped, the 'printer-stopped' value
MAY be included in the job's "job-state-reasons"
attribute.
Note: When an output device is stopped, the device
usually indicates its condition in human readable form
locally at the device. A client can obtain more
complete device status remotely by querying the Printer
object's "printer-state", "printer-state-reasons" and
"printer-state-message" attributes.
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'7' 'canceled': The job has been canceled by a Cancel-Job
operation and the Printer object has completed
canceling the job and all job status attributes have
reached their final values for the job. While the
Printer object is canceling the job, the job remains in
its current state, but the job's "job-state-reasons"
attribute SHOULD contain the 'processing-to-stop-point'
value and one of the 'canceled-by-user', 'canceled-by-
operator', or 'canceled-at-device' value. When the job
moves to the 'canceled' state, the 'processing-to-
stop-point' value, if present, SHALL be removed, but
the `canceled-by-xxx', if present, SHALL remain.
'8' 'aborted': The job has been aborted by the system, usually
while the job was in the 'processing' or 'processing-
stopped' state and the Printer has completed aborting
the job and all job status attributes have reached
their final values for the job. While the Printer
object is aborting the job, the job remains in its
current state, but the job's "job-state-reasons"
attribute SHOULD contain the 'processing-to-stop-point'
and 'aborted-by-system' values. When the job moves to
the 'aborted' state, the 'processing-to-stop-point'
value, if present, SHALL be removed, but the 'aborted-
by-system' value, if present, SHALL remain.
'9' 'completed': The job has completed successfully or with
warnings or errors after processing and all of the job
media sheets have been successfully stacked in the
appropriate output bin(s) and all job status attributes
have reached their final values for the job. The job's
"job-state-reasons" attribute SHOULD contain one of:
'completed-successfully', 'completed-with-warnings', or
'completed-with-errors' values.
The final value for this attribute 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 value of the Job's "job-state-reasons" attribute SHALL be 'none'.
Note: While values cannot be added to the 'job-state' attribute
without impacting deployed clients that take actions upon receiving
"job-state" values, it is the intent that additional "job-state-
reasons" values can be defined and registered without impacting such
deployed clients. In other words, the "job-state-reasons" attribute
is intended to be extensible.
The following standard 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. The job may remain in its current
state or be moved to the 'pending-held' state, depending on
implementation and/or job scheduling policy.
'printer-stopped-partly': The value of the Printer's "printer-
state-reasons" attribute contains the value 'stopped-partly'.
'printer-stopped': The value of the Printer's "printer-state"
attribute is 'stopped'.
'job-interpreting': Job is in the 'processing' state, but more
specifically, the Printer is interpreting the document data.
'job-queued': Job is in the 'processing' state, but more
specifically, the Printer has queued the document data.
'job-transforming': Job is in the 'processing' state, but more
specifically, the Printer is interpreting document data and
producing another electronic representation.
'job-printing': The output device is marking media. This value is
useful for Printers which spend a great deal of time processing
(1) when no marking is happening and then want to show that
marking is now happening or (2) when the job is in the process of
being canceled or aborted while the job remains in the
'processing' state, but the marking has not yet stopped so that
impression or sheet counts are still increasing for the job.
'job-canceled-by-user': The job was canceled by the owner of the
job using the Cancel-Job request, i.e., by a user whose
authenticated identity is the same as the value of the
originating user that created the Job object, or by some other
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authorized end-user, such as a member of the job owner's security
group.
'job-canceled-by-operator': The job was canceled by the operator
using the Cancel-Job request, i.e., by a user who has been
authenticated as having operator privileges (whether local or
remote). If the security policy is to allow anyone to cancel
anyone's job, then this value may be used when the job is
canceled by other than the owner of the job. For such a security
policy, in effect, everyone is an operator as far as canceling
jobs with IPP is concerned.
'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 attribute specifies information about the "job-state" and "job-
state-reasons" attributes in human readable text. If the Printer
object supports this attribute, the Printer object SHALL be able to
generate this message in any of the natural languages identified by
the Printer's "natural-language-supported" attribute (see the
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"attributes-natural-language" operation attribute specified in Section
3.1.3.1).
4.3.9 number-of-documents (integer(0:MAX))
This attribute indicates the number of documents in the job, i.e., the
number of Send-Document, Send-URI, Print-Job, or Print-URI operations
that the Printer has accepted for this job, regardless of whether the
document data has reached the Printer object or not.
Implementations supporting the OPTIONAL Create-Job/Send-Document/Send-
URI operations SHOULD support this attribute so that clients can query
the number of documents in each job.
4.3.10 containing-printer-uri (uri)
This MANDATORY attribute identifies the Printer object that contains
this Job object. This attribute permits a client to query the Printer
object to which the job was submitted given only the Job URI.
4.3.11 output-device-assigned (name)
This attribute identifies the output device to which the Printer
object has assigned this job. If an output device implements an
embedded Printer object, the Printer object NEED NOT set this
attribute. If a print server implements a Printer object, the value
MAY be empty (zero-length string) or not returned until the Printer
object assigns an output device to the job. This attribute is
particularly useful when a single Printer object support multiple
devices (so called "fan-out").
4.3.12 time-at-creation (integer(0:MAX))
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.
4.3.13 time-at-processing (integer(0:MAX))
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
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the Job object is moved into the 'processing' state for the first
time.
4.3.14 time-at-completed (integer(0:MAX))
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.
4.3.15 number-of-intervening-jobs (integer(0:MAX))
This attribute indicates the number of jobs that are "ahead" of this
job in the relative chronological order of expected time to complete
(i.e., the current scheduled order). For efficiency, it is only
necessary to calculate this value when an operation is performed that
requests this attribute.
4.3.16 job-message-from-operator (text)
This attribute provides a message from an operator, system
administrator or "intelligent" process to indicate to the end user the
reasons for modification or other management action taken on a job.
4.3.17 job-k-octets-processed (integer(0:MAX))
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 inclusive SHALL be indicated as being
1, 1025 to 2048 inclusive 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.
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For any of these three attributes, the Printer may choose to return
the special value of 'unknown' rather than choose to not support the
attribute at all.
4.3.18 job-impressions-completed (integer(0:MAX))
This job attribute specifies the number of impressions completed for
the job so far. For printing devices, the impressions completed
includes interpreting, marking, and stacking the output. 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.
4.3.19 job-media-sheets-completed (integer(0:MAX))
This job attribute specifies the media-sheets completed marking and
stacking for the entire job so far whether those sheets have been
processed on one side or on both. This attribute is intended to be a
counter as in the Job Monitoring MIB.
4.3.20 attributes-charset (charset)
This MANDATORY attribute is populated using the value in the client
supplied "attributes-charset" attribute in the create request. It
identifies the charset (coded character set and encoding method) used
by any Job attributes with attribute syntax 'text' and 'name' that
were supplied by the client in the create request. See Section 3.1.3
for a complete description of the "attributes-charset" operation
attribute.
This attribute does not indicate the charset in which the 'text' and
'name' values are stored internally in the Job object. The internal
charset is implementation-defined. The IPP object SHALL convert from
whatever the internal charset is to that being requested in an
operation as specified in Section 3.1.3.
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4.3.21 attributes-natural-language (naturalLanguage)
This MANDATORY 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 a Natural Language
Override may be supplied explicitly for each 'text' and 'name'
attribute value that differs from the value identified by the
"attributes-natural-language" attribute.
4.4 Printer Description Attributes
These attributes form the attribute group called "printer-
description". The following table summarizes these attributes, their
syntax, and whether or not they are MANDATORY for a Printer object to
support. If they are not MANDATORY, they are OPTIONAL.
Note: How these attributes are set by an Administrator is outside the
scope of this specification.
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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 type2 enum | MANDATORY |
+----------------------------+----------------------+----------------+
| charset | charset | MANDATORY |
+----------------------------+----------------------+----------------+
| charset-supported | 1setOf charset | MANDATORY |
+----------------------------+----------------------+----------------+
| natural-language | naturalLanguage | MANDATORY |
+----------------------------+----------------------+----------------+
| natural-language- | 1setOf | MANDATORY |
| supported | naturalLanguage | |
+----------------------------+----------------------+----------------+
| document-format | mimeMediaType | |
+----------------------------+----------------------+----------------+
| document-format- | 1setOf | |
| supported | mimeMediaType | |
+----------------------------+----------------------+----------------+
| printer-is-accepting-jobs | boolean | MANDATORY |
+----------------------------+----------------------+----------------+
| queued-job-count | integer (0:MAX) | |
+----------------------------+----------------------+----------------+
| printer-message-from- | text | |
| operator | | |
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+----------------------------+----------------------+----------------+
| color-supported | boolean | |
+----------------------------+----------------------+----------------+
| pdl-override | type2 keyword | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-up-time | integer (1:MAX) | MANDATORY |
+----------------------------+----------------------+----------------+
| printer-current-time | dateTime | |
+----------------------------+----------------------+----------------+
| multiple-operation-time-out| integer (1:MAX) | |
+----------------------------+----------------------+----------------+
4.4.1 printer-uri (uri)
This MANDATORY Printer attribute contains the URI for the Printer
object. 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 MANDATORY Printer attribute contains the name of the Printer
object. It is a name that is more user friendly than the value of the
"printer-uri" attribute. 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 Printer attribute identifies the location of the device. This
could include things like: "in Room 123A, second floor of building
XYZ".
4.4.4 printer-info (text)
This Printer attribute identifies the descriptive information about
this Printer object. This could include things like: "This printer
can be used for printing color transparencies for HR presentations",
or "Out of courtesy for others, please print only small (1-5 page)
jobs at this printer", or even "This printer is going away on July 1,
1997, please find a new printer".
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4.4.5 printer-more-info (uri)
This Printer attribute contains a URI used to obtain more information
about this specific Printer object. For example, this could be an
HTTP type URI referencing an HTML page accessible to a Web Browser.
The information obtained from this URI is intended for end user
consumption. Features outside the scope of IPP can be accessed from
this URI. The information is intended to be specific to this printer
instance and site specific services (e.g. job pricing, services
offered, end user assistance). The device manufacturer may initially
populate this attribute.
4.4.6 printer-driver-installer (uri)
This Printer attribute contains a URI to use to locate the driver
installer for this Printer object. This attribute is intended for
consumption by automata. The mechanics of print driver installation
is outside the scope of IPP. The device manufacturer may initially
populate this attribute.
4.4.7 printer-make-and-model (text)
This Printer attribute identifies the make and model of the device.
The device manufacturer may initially populate this attribute.
4.4.8 printer-more-info-manufacturer (uri)
This Printer attribute contains a URI used to obtain more information
about this type of device. The information obtained from this URI is
intended for end user consumption. Features outside the scope of IPP
can be accessed from this URI (e.g., latest firmware, upgrades, print
drivers, optional features available). 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 MANDATORY Printer attribute identifies the current state of the
device. The "printer-state reasons" attribute augments the "printer-
state" attribute to give more detailed information about the Printer
in the given printer state.
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A Printer object need only update this attribute before responding to
an operation which requests the attribute; the Printer object NEED NOT
update this attribute continually, since asynchronous event
notification is not part of IPP/1.0. A Printer NEED NOT implement all
values if they are not applicable to a given implementation.
The following standard values are defined:
Value Symbolic Name and Description
'3' 'idle': 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 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.
'4' 'processing': 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.
'5' 'stopped': 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 transitioning
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
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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 Printer attribute supplies additional detail about the device's
state.
Each keyword value MAY have a suffix to indicate its level of
severity. The three levels are: report (least severe), warning, and
error (most severe).
- '-report': This suffix indicates that the reason is a "report".
An implementation may choose to omit some or all reports. Some
reports specify finer granularity about the printer state; others
serve as a precursor to a warning. A report 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 device has detected an error other than one listed in
this document.
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'none': There are not reasons. 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 device has a media jam.
'paused': Someone has paused the Printer object. 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 object from service, and
the device may be powered down or physical removed. In this
state, a Printer object SHALL not produce printed output, and
unless the Printer object is realized by a print server that is
still active, the Printer object SHALL perform no other
operations requested by a client, including returning this value.
If a Printer object had been printing a job when it was shutdown,
the Printer need not resume printing that job when the Printer is
no longer shutdown. If the Printer resumes printing such a job,
it may leave evidence in the printed output of such a shutdown,
e.g. the part printed before the shutdown may be printed a second
time after the shutdown.
'connecting-to-device': The Printer object has scheduled a job on
the output device and is in the process of connecting to a shared
network output device (and might not be able to actually start
printing the job for an arbitrarily long time depending on the
usage of the output device by other servers on the network).
'timed-out': The server was able to connect to the output device
(or is always connected), but was unable to get a response from
the output device.
'stopping': The Printer object is in the process of stopping the
device and will be stopped in a while. When the device is
stopped, the Printer object will change the Printer object's
state to 'stopped'. The 'stopping-warning' reason is never an
error, even for a Printer with a single output device. When an
output-device ceases accepting jobs, the Printer will have this
reason while the output device completes printing.
'stopped-partly': When a Printer object controls more than one
output device, this reason indicates that one or more output
devices are stopped. If the reason is a report, fewer than half
of the output devices are stopped. If the reason is a warning,
fewer than all of the output devices are stopped.
'toner-low': The device is low on toner.
'marker-supply-low': The device 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 device are open.
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'interlock-open': One or more interlock devices on the printer are
unlocked.
'door-open': One or more doors on the device are open.
'input-tray-missing': One or more input trays are not in the
device.
'media-low': At least one input tray is low on media.
'media-empty': At least one input tray is empty.
'output-tray-missing': One or more output trays are not in the
device
'output-area-almost-full': One or more output area is almost full
(e.g. tray, stacker, collator).
'output-area-full': One or more output area is full. (e.g. tray,
stacker, collator)
'marker-supply-low': The device is low on at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-supply-empty: The device is out of at least one marker
supply. (e.g. toner, ink, ribbon)
'marker-waste-almost-full': The device marker supply waste
receptacle is almost full.
'marker-waste-full': The device marker supply waste receptacle is
full.
'fuser-over-temp': The fuser temperature is above normal.
'fuser-under-temp': The fuser temperature is below normal.
'opc-near-eol': The optical photo conductor is near end of life.
'opc-life-over': The optical photo conductor is no longer
functioning.
'developer-low': The device is low on developer.
'developer-empty: The device is out of developer.
'interpreter-resource-unavailable': An interpreter resource is
unavailable (i.e. font, form)
4.4.11 printer-state-message (text)
This Printer attribute specifies the additional information about the
printer state and printer state reasons in human readable text. If
the Printer object supports this attribute, 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 type2 enum)
This MANDATORY Printer attribute specifies the set of supported
operations for this Printer object and contained Job objects. No 32-
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bit enum value for this attribute SHALL exceed 0x8FFF, since these
values are passed in two octets in each Protocol request [IPP-PRO].
The following standard values are defined:
Value Operation Name
0x0000 reserved, not used
0x0001 reserved, not used
0x0002 Print-Job
0x0003 Print-URI
0x0004 Validate-Job
0x0005 Create-Job
0x0006 Send-Document
0x0007 Send-URI
0x0008 Cancel-Job
0x0009 Get-Attributes
0x000A Get-Jobs
0x000B-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.
4.4.13 charset (charset)
This MANDATORY Printer attribute identifies the charset that the
Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system administrator,
or manufacturer, i.e., for "printer-name" (name), "printer-location"
(text), "printer-info" (text), and "printer-make-and-model" (text).
Therefore, the value of the Printer object's "charset" attribute SHALL
also be among the values of the Printer object's "charset-supported"
attribute.
4.4.14 charset-supported (1setOf charset)
This MANDATORY Printer attribute identifies the set of charsets that
the Printer and contained Job objects support in attributes with
attribute syntax 'text' and 'name'. At least the value 'utf-8' SHALL
be present, since IPP objects MUST support the UTF-8 [RFC2044]
charset. If a Printer object supports a charset, it means that for
all attributes of syntax 'text' and 'name' the IPP object SHALL (1)
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accept the charset in requests and return the charset in responses as
needed.
If more charsets than UTF-8 are supported, the IPP object SHALL
perform charset conversion between the charsets as described in
Section 3.2.1.2.
4.4.15 natural-language (naturalLanguage)
This MANDATORY Printer attribute identifies the natural language that
the Printer object has been configured to represent 'text' and 'name'
Printer attributes that are set by the operator, system administrator,
or manufacturer, i.e., for "printer-name" (name), "printer-location"
(text), "printer-info" (text), and "printer-make-and-model" (text).
When returning these Printer attributes, the Printer object MAY return
them in the configured natural language specified by this attribute,
instead of the natural language requested by the client in the
"attributes-natural-language" operation attribute. See Section
3.1.3.1 for the specification of the OPTIONAL multiple natural
language support. Therefore, the value of the Printer object's
"natural-language" attribute SHALL also be among the values of the
Printer object's "natural-language-supported" attribute.
4.4.16 natural-language-supported (1setOf naturalLanguage)
This MANDATORY Printer attribute identifies the natural language(s)
that the Printer object and contained Job objects support in
attributes with attribute syntax 'text' and 'name'. The natural
language(s) supported depends on implementation and/or configuration.
Unlike charsets, IPP objects SHALL accept in requests any natural
language or any Natural Language Override whether supported or not.
If a Printer object supports a natural language, it means that for any
of the attributes for which the Printer or Job object generates
messages, i.e., for the "job-state-message" and "printer-state-
message" attributes and Operation Messages (see Section 3.1.4) in
operation responses, the Printer and Job objects SHALL be able to
generate messages in any of the Printer's supported natural languages.
See section 3.1.3 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.
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4.4.17 document-format (mimeMediaType)
This Printer attribute identifies the document format that the Printer
object has been configured to assume of the client does not supply a
"document-format" operation attribute in any of the operation requests
that supply document data. The standard values for this attribute are
Internet Media types (sometimes called MIME types). For further
details see the description of the 'mimeMediaType' attribute syntax in
Section 4.1.9.
4.4.18 document format-supported (1setOf mimeMediaType)
This Printer attribute identifies the set of document formats that the
Printer object and contained Job objects can support. For further
details see the description of the 'mimeMediaType' attribute syntax in
Section 4.1.9.
4.4.19 printer-is-accepting-jobs (boolean)
This MANDATORY Printer attribute indicates whether the printer is
currently accepting jobs, i.e., is accepting Print-Job, Print-URI, and
Create-Job operations. 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" attributes 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'.
4.4.20 queued-job-count (integer(0:MAX))
This Printer attribute contains a count of the number of jobs that are
either 'pending', 'processing', 'pending-held', or 'processing-
stopped' and is set by the Printer.
4.4.21 printer-message-from-operator (text)
This Printer attribute provides a message from an operator, system
administrator or "intelligent" process to indicate to the end user
information or status of the printer, such as why it is unavailable or
when it is expected to be available.
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4.4.22 color-supported (boolean)
This Printer attribute identifies whether the device 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 in IPP/1.0).
4.4.23 reference-uri-schemes-supported (1setOf uriScheme)
This Printer attribute specifies which URI schemes are supported for
use in the "document-uri" operation attribute of the Print-URI or
Send-URI operation. If a Printer object supports these optional
operations, it MUST support the "reference-uri-schemes-supported"
Printer attribute with at least the following schemed URI values:
'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) a
password. Since many FTP servers require that anonymous FTP
logins supply a password in the form a valid Internet email
address, the Printer object MUST be able to generate such a
password (syntactically correct, yet perhaps semantically
meaningless) if needed.
The Printer object MAY OPTIONALLY support other URI schemes (see
section 4.1.6).
4.4.24 pdl-override (type2 keyword)
This MANDATORY Printer attribute expresses the ability for a
particular Printer implementation to either attempt to override
document data instructions with IPP attributes or not.
This attribute takes on the following values:
- 'attempted': This value indicates that the Printer object
attempts to make the IPP attribute values take precedence over
embedded instructions in the document data, however there is no
guarantee.
- 'not-attempted': This value indicates that the Printer object
makes no attempt to make the IPP attribute values take precedence
over embedded instructions in the document data.
Section 15 contains a full description of how this attribute interacts
with and affects other IPP attributes, especially the "ipp-attribute-
fidelity" attribute.
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4.4.25 printer-up-time (integer(1:MAX))
This MANDATORY Printer attribute 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-
at-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-at-creation", "time-at-processing", and "time-
at-completed"). In the second case, the Printer object SHOULD reset
those attributes 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.
4.4.26 printer-current-time (dateTime)
This Printer attribute 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-at-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.
4.4.27 multiple-operation-time-out (integer(1:MAX))
This Printer 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 before taking one of the
actions indicated in section 3.3.1.
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5. Conformance
This section describes conformance issues and requirements. This
document introduces model entities such as objects, operations,
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 support all MANDATORY operations as defined
in this document. For each attribute included in an operation
request, a conforming client SHALL supply a value whose type and value
syntax conforms to the requirements of the Model document as specified
in Sections 3 and 4. A conforming client MAY supply any registered
extensions and/or private extensions in an operation request, as long
as they meet the requirements in Section 6.
Otherwise, there are no conformance requirements placed on the user
interfaces provided by IPP clients or their applications. For
example, one application might not allow an end user to submit
multiple documents per job, while another does. One application might
first query a Printer object in order to supply a graphical user
interface (GUI) dialogue box with supported and default values whereas
a different implementation might not.
When sending a Get-Attributes or create request, an IPP client NEED
NOT supply any attributes that can OPTIONALLY be supplied by the
client.
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. For presentation purposes,
truncation of long attribute values is not recommended. A recommended
approach would be for the client implementation to allow the user to
scroll through long attribute values.
A 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.
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5.2 IPP Object Conformance Requirements
This section specifies the conformance requirements for conforming
implementations with respect to objects, operations, and attributes.
5.2.1 Objects
Conforming 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 IPP objects SHALL support all operation attributes and all
values of such attributes. The following section on object attributes
specifies the support required for object attributes.
5.2.3 IPP Object Attributes
Conforming IPP objects SHALL support all of the MANDATORY object
attributes, as defined in this specification in the indicated
sections.
If an object supports an attribute, it SHALL support only those values
specified in this document or through the extension mechanism
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described in section 5.2.4. 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.
5.2.4 Extensions
A conforming IPP object MAY support registered extensions and private
extensions, as long as they meet the requirements specified in Section
6.
For each attribute included in an operation response, a conforming IPP
object SHALL return a value whose type and value syntax conforms to
the requirement of the Model document as specified in Sections 3 and
4.
5.2.5 Attribute Syntaxes
An IPP object 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, an IPP object
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 charset and Natural Language Requirements
All clients and IPP objects SHALL support the 'utf-8' charset as
defined in section 4.1.7.
IPP objects MUST be able to accept any client request which correctly
uses the "attributes-natural-language" operation attribute or the
Natural Language Override method on any individual attribute whether
or not the natural language is supported by the IPP object. If an IPP
object supports a natural language, then it MUST be able to translate
(perhaps by table lookup) all generated 'text' or 'name' attribute
values into one of the supported languages (see section 3.1.3). That
is, the IPP object that supports a natural language NEED NOT be a
general purpose translator of any arbitrary 'text' or 'name' value
supplied by the client into that natural language, however the object
MUST be able to translate (automatically generate) any of its own
attribute values and messages into that natural language.
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5.4 Security Conformance Requirements
All clients and IPP objects (that support the HTTP/1.1 mapping as
defined in the IPP/1.0 Protocol Specification [IPP-PRO]) SHALL support
the two authentication mechanisms for HTTP/1.1 as defined in RFC 2068
[RFC2068] and RFC 2069 [RFC2069].
If a client or an IPP object supports secure communication channels,
then that client or IPP object MUST support SSL3. SSL3 allows for
clients and objects to negotiate the required security level.. Since
Transport Layer Security (TLS) plans to support backwards
compatibility with SSL3, then all implementations that support SSL3
will be conformant with TLS as soon as TLS becomes an IETF standards
track specification.
For a detailed discussion of security considerations, see section 8.
6. IANA Considerations (registered and private extensions)
This section describes how IPP can be extended.
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 while it is still chartered, or
- the Printer Working Group [PWG] after the IPP working group is
disbanded
who will review the proposal and work with IANA to register the
additional keywords and enums. IANA assigns the number for enum
values and keeps the registry of keywords and enums.
"type3": Implementers can, at any time, add new keyword and enum
values by submitting the complete specification directly to IANA,
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no IPP working group or Printer Working Group review is required.
IANA assigns the number for enum values and keeps the registry of
keywords and enums. IANA is responsible for ensuring new
keywords are unique.
"type4": Anyone (system administrators, system integrators, site
managers, etc.) can, at any time, add new installation-defined
values (keywords, but not 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.
Note: Attributes with type 4 keywords also allow the 'name'
attribute syntax for administrator defined names. Such names are
not registered.
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]. For example, if the company
XYZ Corp. had obtained the domain name "XYZ.com", then a private
keyword 'abc' would be: 'xyz.com-abc'.
Note: RFC 1035 [RFC1035] indicates that while upper and lower case
letters are allowed in domain names, no significance is attached to
the case. That is, two names with the same spelling but different
case are to be treated as if identical. Also, the labels in a domain
name must follow the rules for ARPANET host names: They must start
with a letter, end with a letter or digit, and have as interior
characters only letters, digits, and hyphen. Labels must be 63
characters or less. Labels are separated by the "." character.
For private (unregistered) enum extension, implementers SHALL use
values in the reserved integer range which is 2**30 to 2**31-1.
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6.2 Registration of MIME types/sub-types for document-formats
The "document-format" attribute's syntax is 'mimeMediaType'. This
means that valid values are Internet Media Types. RFC 2045 [RFC2045]
defines the syntax for valid Internet media types. IANA is the
registry for all Internet media types.
6.3 Attribute Extensibility
Attribute names are type2 keywords. Therefore, new attributes may be
registered and have the same status as attributes in this document by
following the type2 extension rules.
6.4 Attribute Syntax Extensibility
Attribute syntaxes are like type2 enums. Therefore, new attribute
syntaxes may be registered and have the same status as attribute
syntaxes in this document by following the type2 extension rules. The
value codes that identify each of the attribute syntaxes are assigned
in the protocol specification [IPP-PRO].
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 0 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
(as described in Section 3.1.3.1). In addition, the client MAY
separately and individually identify the Natural Language Override 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
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'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 "charset", "charset-supported", "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 (name)
job-state-message (text)
job-message-from-operator (text)
Printer Attributes:
printer-name (name)
printer-location (text)
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
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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
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.
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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.
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 Internet Draft which are stored on
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anonymous FTP sites, are good examples of unprotected documents. 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 printer 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
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
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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 HTTP/1.1 and SSL3 with null security. This
allows all implementation to be compliant with TLS as TLS 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
policy established by a site administrator, and the selection made by
the client. This requires that the correct 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.
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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 objects 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.
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.
[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).
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[IANA-MT]
IANA Registry of Media Types: ftp://ftp.isi.edu/in-
notes/iana/assignments/media-types/
[IPP-PRO]
Herriot, R., Butler, S., Moore, P., Tuner, R., " 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.
[ISO10175]
ISO/IEC 10175 Document Printing Application (DPA), June 1996.
[LDPA]
T. Hastings, S. Isaacson, M. MacKay, C. Manros, D. Taylor, P.
Zehler, "LDPA - Lightweight Document Printing Application",
October 1996,
ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/ldpa8.pdf.gz
[P1387.4]
Kirk, M. (editor), POSIX System Administration - Part 4: Printing
Interfaces, POSIX 1387.4 D8, 1994.
[PSIS] Herriot, R. (editor), X/Open A Printing System
Interoperability Specification (PSIS), August 1995.
[PWG]
Printer Working Group, http://www.pwg.org.
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[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.
[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.
[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.
[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.
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[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.
[RFC2119]
S. Bradner, "Key words for use in RFCs to Indicate Requirement
Levels", RFC 2119 , March 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
10. Copyright Notice
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
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Provo, UT 84606
Phone: 801-861-7366
Fax: 801-861-2517
EMail: scott_isaacson@novell.com
Tom Hastings
Xerox Corporation
701 S. Aviation Blvd.
El Segundo, CA 90245
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: 650-786-8995
Fax: 650-786-7077
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:
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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
Babek Jahromi, Microsoft
David Kellerman - Northlake Software
Rick Landau - Digital
Greg LeClair - Epson
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
Tetsuya Morita - Ricoh
Yuichi Niwa - Ricoh
Pat Nogay - IBM
Ron Norton - Printronics
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.
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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 inter-operate with another implementation which does
include the option, though perhaps with reduced functionality. In the
same vein an implementation which does include a particular option
MUST be prepared to inter-operate 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 (see section 4.1.3). Attribute
names, some attribute values, attribute syntaxes, and attribute group
names are represented as keywords.
12.2.2 Attributes
An attribute is an item of information that is associated with an
instance of an IPP object. An attribute consists of an attribute name
and one or more attribute values. Each attribute has a specific
attribute syntax. All object attributes are defined in section 4 and
all operation attributes are defined in section 3.
Job Template Attributes 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.
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12.2.2.1 Attribute Name
Each attribute is uniquely identified in this document by its
attribute name. An attribute name is a keyword. The keyword
attribute name is given in the section header describing that
attribute. In running text in this document, attribute names are
indicated inside double quotation marks (") where the quotation marks
are not part of the keyword itself.
12.2.2.2 Attribute Group Name
Related attributes are grouped into named groups. The name of the
group is a keyword. The group name may be used in place of naming all
the attributes in the group explicitly. Attribute groups are defined
in section 3.
12.2.2.3 Attribute Value
Each attribute has one or more values. Attribute values are
represented in the syntax type specified for that attribute. In
running text in this document, attribute values are indicated inside
single quotation marks ('), whether their attribute syntax is keyword,
integer, text, etc. where the quotation marks are not part of the
value itself.
12.2.2.4 Attribute Syntax
Each attribute is defined using an explicit syntax type. In this
document, each syntax type is defined as a keyword with specific
meaning. The 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 the
Printer object's "supported values" attributes. The device behind a
Printer object may exhibit a behavior that corresponds to some IPP
attribute, but if the Printer object, when queried for that attribute,
doesn't respond with the attribute, then as far as IPP is concerned,
that implementation does not support that feature. If the Printer
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object's "xxx-supported" attribute is not populated with a particular
value (even if that value is a legal value for that attribute), then
that Printer object does not support that particular value.
A conforming implementation 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-
format-supported" attribute populated with a set of values, possibly
only one, taken from the entire set of possible values defined for
that attribute. This limited set of values represents the Printer's
set of supported document formats. Supporting an attribute and some
set of values for that attribute enables IPP end users to be aware of
and make use of those features associated with that attribute and
those values. If an implementation chooses to not support an
attribute or some specific value, then IPP end users would have no
ability to make use of that feature within the context of IPP itself.
However, due to existing practice and legacy systems which are not IPP
aware, there might be some other mechanism outside the scope of IPP to
control or request the "unsupported" feature (such as embedded
instructions within the document data itself).
For example, consider the "finishings-supported" attribute.
1) If a Printer object is not physically capable of stapling, the
"finishings-supported" attribute MUST NOT be populated with the
value of 'staple'.
2) A Printer object is physically capable of stapling, however an
implementation chooses not to support stapling in the IPP
"finishings" attribute. In this case, 'staple' SHALL NOT be a
value in the "finishings-supported" Printer object attribute.
Without support for the value 'staple', an IPP end user would
have no means within the protocol itself to request that a Job be
stapled. However, an existing document data formatter might be
able to request that the document be stapled directly with an
embedded instruction within the document data. In this case, the
IPP implementation does not "support" stapling, however the end
user is still able to have some control over the stapling of the
completed job.
3) A Printer object is physically capable of stapling, and an
implementation chooses to support stapling in the IPP
"finishings" attribute. In this case, 'staple' SHALL be a value
in the "finishings-supported" Printer object attribute. Doing so,
would enable end users to be aware of and make use of the
stapling feature using IPP attributes.
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Even though support for Job Template attributes by a Printer object is
OPTIONAL, it is RECOMMENDED that if the device behind a Printer object
is capable of realizing any feature or function that corresponds to an
IPP attribute and some associated value, then that implementation
SHOULD support that IPP attribute and value.
The set of values in any of the supported value attributes is set
(populated) by some administrative process or automatic sensing
mechanism that is outside the scope of 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 be exposed to the end user through the IPP protocol.
Also, since a Printer object may represent a logical print device (not
just a physical device) the actual process for supporting a value is
undefined and left up to the implementation. However, if a Printer
object supports a value, some manual human action may be needed to
realize the semantic action associated with the value, but no end user
action is required.
For example, if one of the values in the "finishings-supported"
attribute is 'staple', the actual process might be an automatic staple
action by a physical device controlled by some command sent to the
device. Or, the actual process of stapling might be a manual action
by an operator at an operator attended Printer object.
For another example of how supported attributes function, consider an
system administrator who desires to control all print jobs so that no
job sheets are printed in order to conserve paper. To force no job
sheets, the system administrator sets the only supported value for the
"job-sheets-supported" attribute to 'none'. In this case, if a client
requests anything except 'none', the create request is rejected or the
"job-sheets" value is ignored (depending on the value of "ipp-
attribute-fidelity"). To force the use of job start/end sheets on all
jobs, the administrator does not include the value 'none' in the "job-
sheets-supported" attribute. In this case, if a client requests
'none', the create request is rejected or the "job-sheets" value is
ignored (again depending on the value of "ipp-attribute-fidelity").
12.2.4 print-stream page
A "print-stream page" is a page according to the definition of pages
in the language used to express the document data.
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12.2.5 impression
An "impression" is the image (possibly many print-stream pages in
different configurations) imposed onto a single media page.
13. APPENDIX B: Status Codes and Suggested Status Code Messages
This section defines status code enum keywords and values that are
used to provide semantic information on the results of an operation
request. Each operation response MUST include a status code. 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, since it MAY not be returned to
the application.
The prefix of the status keyword defines the class of response as
follows:
"informational" - Request received, continuing process
"successful" - The action was successfully received, understood,
and accepted
"redirection" - Further action must be taken in order to complete
the request
"client-error" - The request contains bad syntax or cannot be
fulfilled
"server-error" - The IPP object failed to fulfill an apparently
valid request
Since IPP status codes are type2 enums, they are extensible. IPP
clients 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-xxx-yyy" is
received by the client, it can safely assume that there was something
wrong with its request and treat the response as if it had received a
"client-error-bad-request" status code. In such cases, IPP
applications SHOULD present the OPTIONAL message (if present) to the
end user since the message is likely to contain human readable
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information which will help to explain the unusual status. The name
of the enum is the suggested status message for US English.
The status code values range from 0x0000 to 0x7FFF. The value ranges
for each status code class are as follows:
"successful" - 0x0000 to 0x00FF
"informational" - 0x0100 to 0x01FF
"redirection" - 0x0200 to 0x02FF
"client-error" - 0x0400 to 0x04FF
"server-error" - 0x0500 to 0x05FF
The top half (128 values) of each range (0x0n40 to 0x0nFF, for n = 0
to 5) is reserved for private use within each status code class.
Values 0x0600 to 0x7FFF are reserved for future assignment and SHALL
not be used.
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. Section
15.3 describes the algorithm for processing IPP attributes for the
create and Job-Validate operations, including returning status codes.
13.1.1 Informational
This class of status code indicates a provisional response and is to
be used for informational purposes only.
There are no status codes defined in IPP/1.0 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 create or Validate-Job request has succeeded, but some attributes
were ignored or unsupported values were substituted with supported
values in order to process the job without rejecting it. See section
3.2.1.2 that describes the Unsupported Attributes returned in a Print-
Job Response and section that describes the processing of attributes.
13.1.2.3 successful-ok-conflicting-attributes (0x0002)
The create or Validate-Job request has succeeded, but some attribute
values conflicted with the values of other attributes. These
conflicting values were either (1) substituted with (supported) values
or (2) the attributes were removed in order to process the job without
rejecting it. See section 3.2.1.2 that describes the Unsupported
Attributes returned in a Print-Job Response.
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 IPP object SHOULD return a message
containing an explanation of the error situation and whether it is a
temporary or permanent condition.
13.1.4.1 client-error-bad-request (0x0400)
The request could not be understood by the IPP object due to malformed
syntax. The IPP application SHOULD NOT repeat the request without
modifications.
13.1.4.2 client-error-forbidden (0x0401)
The IPP object understood the request, but is refusing to fulfill it.
Additional authentication information or authorization credentials
will not help and the request SHOULD NOT be repeated. This status
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code is commonly used when the IPP object does not wish to reveal
exactly why the request has been refused or when no other response is
applicable.
13.1.4.3 client-error-not-authenticated (0x0402)
The request requires user authentication. The IPP client may repeat
the request with suitable authentication information. If the request
already included authentication information, then this status code
indicates that authorization has been refused for those credentials.
If this response contains the same challenge as the prior response,
and the user agent has already attempted authentication at least once,
then the response message may contain relevant diagnostic information.
This status codes reveals more information than "client-error-
forbidden".
13.1.4.4 client-error-not-authorized (0x0403)
The requester is not authorized to perform the request. Additional
authentication information or authorization credentials will not help
and the request SHOULD NOT be repeated. This status code is used when
the IPP object wishes to reveal that the authentication information is
understandable, however, the requester is explicitly not authorized to
perform the request. This status codes reveals more information than
"client-error-forbidden" and "client-error-not-authenticated".
13.1.4.5 client-error-not-possible (0x0404)
This status code is used when the request is for something that can
not happen. For example, there might be a request to cancel a job
that has already been canceled or aborted by the system. The IPP
client SHOULD NOT repeat the request.
13.1.4.6 client-error-timeout (0x0405)
The client did not produce a request within the time that the IPP
object was prepared to wait. For example, a client issued a Create-
Job operation and then, after a long period of time, issued a Send-
Document operation and this error status code was returned in response
to the Send-Document request (see section 3.3.1). The IPP object
might have been forced to clean up resources that had been held for
the waiting additional Documents. The IPP object was forced to close
the Job since the client took too long. The client SHOULD NOT repeat
the request without modifications.
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13.1.4.7 client-error-not-found (0x0406)
The IPP object has not found anything matching the request URI. No
indication is given of whether the condition is temporary or
permanent. For example, a client with an old reference to a Job (a
URI) tries to cancel the Job, however in the mean time the Job might
have been completed and all record of it at the Printer has been
deleted. This status code, 'client-error-not-found' is returned
indicating that the referenced Job can not be found. This error
status code is also used when a client supplies a URI as a reference
to the document data in either a Print-URI or Send-URI operation
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.
13.1.4.8 client-error-gone (0x0407)
The requested object is no longer available and no forwarding address
is known. This condition should be considered permanent. Clients
with link editing capabilities should delete references to the request
URI after user approval. If the IPP object does not know or has no
facility to determine, whether or not the condition is permanent, the
status code "client-error-not-found" should be used instead.
This response is primarily intended to assist the task of maintenance
by notifying the recipient that the resource is intentionally
unavailable and that the IPP object administrator desires that remote
links to that resource be removed. It is not necessary to mark all
permanently unavailable resources as "gone" or to keep the mark for
any length of time -- that is left to the discretion of the IPP object
administrator.
13.1.4.9 client-error-request-entity-too-large (0x0408)
The IPP object is refusing to process a request because the request
entity is larger than the IPP object is willing or able to process.
An IPP Printer returns this status code when it limits the size of
print jobs and it receives a print job that exceeds that limit or when
the attributes are so many that their encoding causes the request
entity to exceed IPP object capacity.
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13.1.4.10 client-error-request-uri-too-long (0x0409)
The IPP object is refusing to service the request because the request
URI is longer than the IPP object 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
IPP object is under attack by a client attempting to exploit security
holes present in some IPP objects using fixed-length buffers for
reading or manipulating the Request-URI.
13.1.4.11 client-error-document-format-not-supported (0x040A)
The IPP object is refusing to service the request because the document
data is in a format, as specified in the "document-format" operation
attribute, that is not supported by the Printer object. This error is
returned independent of the client-supplied "ipp-attribute-fidelity".
The Printer object SHALL return this status code, even if there are
other attributes that are not supported as well, since this error is a
bigger problem than with Job Template attributes.
13.1.4.12 client-error-attribute-not-supported (0x040B)
In a create request, if the Printer object does not support one or
more attributes or attribute values supplied in the request and the
client supplied the "ipp-attributes-fidelity" operation attribute with
the 'true' value, the Printer object shall return this status code.
For example, if the request indicates 'iso-a4' media, but that media
type is not supported by the Printer object. Or, if the client
supplies an optional attribute and the attribute itself is not even
supported by the Printer. If the "ipp-attribute-fidelity" attribute
is 'false', the Printer SHALL ignore or substitute values for
unsupported attributes and values rather than reject the request and
return this status code.
For any operation where a client requests attributes (such as a Get-
Jobs or Get-Attributes operation), if the IPP object does not support
one or more of the requested attributes, the IPP object simply ignores
the unsupported requested attributes and processes the request as if
they had not been supplied, rather than returning this status code.
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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-conflicting-attributes (0x040E)
The create or Validate-Job request is rejected because some attribute
values conflicted with the values of other attributes. See section
3.2.1.2 that describes the Unsupported Attributes returned in a Print-
Job Response.
13.1.5 Server Error Status Codes
This class of status codes indicates cases in which the IPP object is
aware that it has erred or is incapable of performing the request.
The IPP object SHOULD include a message containing an explanation of
the error situation, and whether it is a temporary or permanent
condition.
13.1.5.1 server-error-internal-error (0x0500)
The IPP object encountered an unexpected condition that prevented it
from fulfilling the request. This error status code differs from
"server-error-temporary-error" in that it implies a more permanent
type of internal error. It also differs from "server-error-device-
error" in that it implies an unexpected condition (unlike a paper-jam
or out-of-toner problem which is undesirable but expected). This
error status code indicates that probably some knowledgeable human
intervention is required.
13.1.5.2 server-error-operation-not-supported (0x0501)
The IPP object does not support the functionality required to fulfill
the request. This is the appropriate response when the IPP object does
not recognize an operation or is not capable of supporting it.
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13.1.5.3 server-error-service-unavailable (0x0502)
The IPP object is currently unable to handle the request due to a
temporary overloading or maintenance of the IPP object. The
implication is that this is a temporary condition which will be
alleviated after some delay. If known, the length of the delay may be
indicated in the message. If no delay is given, the IPP application
should handle the response as it would for a "server-error-temporary-
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 IPP object does not support, or refuses to support, the IPP
protocol version that was used in the request message. The IPP object
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 IPP object.
A conforming IPP/1.0 client SHALL specify the valid version ('1.0') on
each request. A conforming IPP/1.0 object SHALL NOT return this
status code to a conforming IPP/1.0 client. An IPP object 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 object
processes a Print or Send operation. The response contains the true
Job Status (the values of the "job-state" and "job-state-reasons"
attributes). Additional information can be returned in the optional
"job-state-message" attribute value or in the OPTIONAL status message
that describes the error in more detail. This error status code is
only returned in situations where the Printer is unable to accept the
create request because of such a device error. For example, if the
Printer is unable to spool, and can only accept one job at a time, the
reason it might reject a create request is that the printer currently
has a paper jam. In many cases however, where the Printer object can
accept the request even though the Printer has some error condition,
the 'successful-ok' status code will be returned. In such a case, the
client would look at the returned Job Object Attributes or later query
the Printer to determine its state and state reasons.
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13.1.5.6 server-error-temporary-error (0x0505)
A temporary error such as a buffer full write error, a memory overflow
(i.e. the document data exceeds the memory of the Printer), or a disk
full condition, occurs while the IPP Printer processes an operation.
The client MAY try the unmodified request again at some later point in
time with an expectation that the temporary internal error condition
may have been cleared. Alternatively, as an implementation option, a
Printer object MAY delay the response until the temporary condition is
cleared so that no error is returned.
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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
successful-ok-conflicting-attributes x x x x x x
client-error-bad-request x x x x x x x x x
client-error-forbidden x x x x x x x x x
client-error-not-authenticated x x x x x x x x x
client-error-not-authorized x x x x x x x x x
client-error-not-possible x x x x x x x x x
client-error-timeout x x x x x x x x x
client-error-not-found x x x x x x x x x
client-error-gone x x x x x x x x x
client-error-request-entity-too-large x x x x x x x x x
client-error-request-uri-too-long x x x x x x x x x
client-error-document-format-not- x x x x
supported
client-error-attribute-not- x x x x
supported
client-error-uri-scheme-not-supported x x
client-error-charset-not-supported x x x x x x x x x
client-error-conflicting-attributes x x x x x x
server-error-internal-error x x x x x x x x x
server-error-operation-not-supported x x x x
server-error-service-unavailable x x x x x x x x x
server-error-version-not-supported x x x x x x x x x
server-error-device-error x x x x x
server-error-temporary-error x x x x x
14. APPENDIX C: "media" keyword values
Standard keyword values are taken from several sources.
Standard values are defined (taken from DPA[ISO10175] and the Printer
MIB[RFC1759]):
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'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
'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
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'na-9x11-envelope': Specifies the North American 9x11 inch envelope
'na-10x14-envelope': Specifies the North American 10x14 inch
envelope
'na-number-9-envelope': Specifies the North American number 9
business envelope
'na-6x9-envelope': Specifies the North American 6x9 inch envelope
'na-10x15-envelope': Specifies the North American 10x15 inch
envelope
The following standard values are defined for the less commonly used
media (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:
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'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
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
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'iso-b1': Specifies the ISO B1 size: 707 mm by 1000 mm as defined
in ISO 216
'iso-b2': Specifies the ISO B2 size: 500 mm by 707 mm as defined in
ISO 216
'iso-b3': Specifies the ISO B3 size: 353 mm by 500 mm as defined in
ISO 216
'iso-b4': Specifies the ISO B4 size: 250 mm by 353 mm as defined in
ISO 216
'iso-b5': Specifies the ISO B5 size: 176 mm by 250 mm as defined in
ISO 216
'iso-b6': Specifies the ISO B6 size: 125 mm by 176 mm as defined in
ISO 216
'iso-b7': Specifies the ISO B7 size: 88 mm by 125 mm as defined in
ISO 216
'iso-b8': Specifies the ISO B8 size: 62 mm by 88 mm as defined in
ISO 216
'iso-b9': Specifies the ISO B9 size: 44 mm by 62 mm as defined in
ISO 216
'iso-b10': Specifies the ISO B10 size: 31 mm by 44 mm as defined in
ISO 216
'na-letter': Specifies the North American letter size: 8.5 inches
by 11 inches
'na-legal': Specifies the North American legal size: 8.5 inches by
14 inches
'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
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'na-9x11-envelope': Specifies the North American 9x11 inch envelope
size
'na-10x14-envelope': Specifies the North American 10x14 inch
envelope size
'na-number-9-envelope': Specifies the North American number 9
business envelope size
'na-6x9-envelope': Specifies the North American 6x9 envelope size
'na-10x15-envelope': Specifies the North American 10x15 envelope
size
'monarch-envelope': Specifies the Monarch envelope size (3.87 x 7.5
in)
'jis-b0': Specifies the JIS B0 size: 1030mm x 1456mm
'jis-b1': Specifies the JIS B1 size: 728mm x 1030mm
'jis-b2': Specifies the JIS B2 size: 515mm x 728mm
'jis-b3': Specifies the JIS B3 size: 364mm x 515mm
'jis-b4': Specifies the JIS B4 size: 257mm x 364mm
'jis-b5': Specifies the JIS B5 size: 182mm x 257mm
'jis-b6': Specifies the JIS B6 size: 128mm x 182mm
'jis-b7': Specifies the JIS B7 size: 91mm x 128mm
'jis-b8': Specifies the JIS B8 size: 64mm x 91mm
'jis-b9': Specifies the JIS B9 size: 45mm x 64mm
'jis-b10': Specifies the JIS B10 size: 32mm x 45mm
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.
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15.1 Fidelity
If there is a conflict between what the client requests and what a
Printer object supports, the client may request one of two possible
conflict handling mechanisms:
1) either reject the job since the job can not be processed exactly
as specified, or
2) allow the Printer to make any changes necessary to proceed with
processing the Job the best it can.
In the first case the client is indicating to the Printer object:
"Print the job exactly as specified with no exceptions, and if that
can't be done, don't even bother printing the job at all." In the
second case, the client is indicating to the Printer object: "It is
more important to make sure the job is printed rather than be
processed exactly as specified; just make sure the job is printed even
if client supplied attributes need to be changed or ignored."
The IPP model accounts for this situation by introducing an "ipp-
attribute-fidelity" attribute.
In a create request, "ipp-attribute-fidelity" is a boolean operation
attribute that is OPTIONALLY supplied by the client. The value 'true'
indicates that total fidelity to client supplied 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 SHALL ignore them or substitute any
supported value for unsupported values, respectively. The Printer may
choose to substitute the default value associated with that attribute,
or use some other supported value that is similar to the unsupported
requested value. For example, if a client supplies a "media" value of
'na-letter', the Printer may choose to substitute 'iso-a4' rather than
a default value of 'envelope'. If the client does not supply the "ipp-
attribute-fidelity" attribute, the Printer assumes a value of 'false'.
Each Printer implementation MUST support both types of "fidelity"
printing (that is whether the client supplies a value of 'true' or
'false'):
- If the client supplies 'false' or does not supply the attribute,
the Printer object SHALL always accept the request by ignoring
unsupported attributes and by substituting unsupported values of
supported attributes with supported values.
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- If the client supplies 'true', the Printer object SHALL reject
the request if the client supplies unsupported attributes.
Since a client can always query a Printer to find out exactly what is
and is not supported, "ipp-attribute-fidelity" set to 'false' is
useful when:
1) The End-User uses a command line interface to request attributes
that might not be supported.
2) In a GUI context, if the End User expects the job might be moved
to another printer and prefers a sub-optimal result to nothing at
all.
3) The End User just wants something reasonable in lieu of nothing
at all.
15.2 Page Description Language (PDL) Override
If there is a conflict between the value of an IPP Job Template
attribute and a corresponding instruction in the document data, the
value of the IPP attribute SHOULD take precedence over the document
instruction. Consider the case where a previously formatted file of
document data is sent to an IPP Printer. In this case, if the client
supplies any attributes at job submission time, the client desires
that those attributes override the embedded instructions. Consider
the case were a previously formatted document has embedded in it
commands to load 'iso-a4' media. However, the document is passed to
an end user that only has access to a printer with 'na-letter' media
loaded. That end user most likely wants to submit that document to an
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 that describes the Printer objects
capabilities to override instructions embedded in the PDL data stream.
The value of the "pdl-override-supported" attribute is configured by
means outside IPP/1.0.
This MANDATORY Printer attribute takes on the following values:
- 'attempted': This value indicates that the Printer object
attempts to make the IPP attribute values take precedence over
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embedded instructions in the document data, however there is no
guarantee.
- 'not-attempted': This value indicates that the Printer object
makes no attempt to make the IPP attribute values take precedence
over embedded instructions in the document data.
At job processing time, an implementation that supports the value of
'attempted' might do one of several different actions:
1) generate an output device specific command sequence to realize
the feature represented by the IPP attribute value
2) parse the document data itself and replace the conflicting
embedded instruction with a new embedded instruction that matches
the intent of the IPP attribute value
3) indicate to the Printer that external supplied attributes take
precedence over embedded instructions and then pass the external
IPP attribute values to the document data interpreter
4) anything else that allows for the semantics that IPP attributes
override embedded document data instructions.
Since 'attempted' does not offer any type of guarantee, even though a
given Printer object might not do a very "good" job of attempting to
ensure that IPP attributes take a higher precedence over instructions
embedded in the document data, it would still be a conforming
implementation.
At job processing time, an implementation that supports the value of
'not-attempted' might do one of the following actions:
1) Simply pre-pend the document data with the PDL instruction that
corresponds to the client-supplied PDL attribute, such that if
the document data also has the same PDL instruction, it will
override what the Printer object pre-pended. In other words,
this implementation is using the same implementation semantics
for the client-supplied IPP attributes as for the Printer object
defaults.
2) Actually modify the embedded instructions to correspond to the
semantics of the client-supplied IPP attributes.
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 when the document data contains embedded
instructions depends on the ability of the Printer to override the
instructions embedded in the document data with the semantics of the
IPP attributes. If the document data attributes can be overridden
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("pdl-override-supported" set to 'attempted'), the Printer makes an
attempt to use the IPP attributes when processing the Job. If the
document data attributes can not be overridden ("pdl-override-
supported" set to 'not-attempted'), the Printer makes no attempt to
override the embedded document data instructions with the IPP
attributes when processing the Job, and hence, the IPP attributes may
fail to affect the Job processing and output when the corresponding
instruction is embedded in the document data.
15.3 Suggested Operation Processing Algorithm for Create and Validate-
Job operations
When a Printer object receives a create request, the Printer object
either accepts or rejects the request. When a Printer object receives
a Validate-Job request it performs the same validation and returns the
same results as for the Print-Job operation. In order to determine
whether or not to accept or reject the request, the Printer SHOULD use
the following algorithm or an equivalent one that produces the same
results, including the status code precedence.
In the following algorithm, processing continues step by step until a
"rejects the request _" is encountered or the last step is reached.
Each error return to the client SHOULD be made before the entire
Document Content data stream is accepted, so that the client need not
send all of the data for a request that is being rejected.:
1. The Printer object checks to see if the requested major and minor
version number is supported. If not, the Printer object rejects
the request by returning the 'server-error-version-not-supported'
status code in the response. The checking of the minor version
number is implementation dependent. Some implementations MAY
accept all minor version numbers, while others MAY only accept
ones that are equal to or lower than the highest one that they
support.
2. The Printer object checks to see if the operation is supported as
indicated in the Printer object's "printer-operations-supported"
attribute. If not, the Printer rejects the request and returns
the 'server-error-operation-not-supported' status code in the
response.
3. The Printer object checks to see if the client-supplied
"attributes-charset" Operation attribute contains a supported
charset value, i.e., the value is contained in the Printer
object's "charset-supported" attribute. If not, the Printer
object rejects the request and returns the 'client-error-charset-
not-supported' status code.
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4. The Printer object checks to see if the client-supplied
"attributes-natural-language" Operation attribute contains a
supported natural language, i.e., the value is contained in the
Printer object's "natural-language-supported" attribute. If not,
the Printer object flags the value as not supported, but does not
reject the request (even if "ipp-attribute-fidelity" is 'true').
5. For the Print-URI and Send-URI operations, the IPP object checks
to see if the client-supplied "document-uri" Operation attribute
contains a supported scheme, i.e., the value is contained in the
Printer object's "reference-uri-schemes-supported" attribute. If
it is not supported, the Printer object rejects the request and
returns the 'client-error'-uri-scheme-not-supported' status code.
The Printer object checks the length of the "document-uri" value.
If it exceed the implementation-defined maximum length, the
Printer object rejects the request and returns the 'client-error-
request-uri-too-long' status code.
6. The Printer object checks to see if the client-supplied
"document-format" operation attribute, if supplied, contains a
supported document format value, i.e., the value is contained in
the Printer object's "document-format-supported" attribute. If
it is not supported, the Printer object rejects the request and
returns the 'client-error-document-format-not-supported' status
code. If the client did not supply a "document-format" operation
attribute, the Printer object assumes that the document format is
that specified by the Printer's "document-format " attribute.
7. The Printer object checks to see if the client supplied an "ipp-
attribute-fidelity" Operation attribute. If the attribute is
missing (not supplied by the client), the Printer assumes that
the value is 'false'.
8. The Printer object loops through all the client-supplied Job
Template attributes, checking to see if the supplied attribute
and values are supported, e.g., the value of the "xxx" attribute
in the request is one of the values in the Printer's "xxx-
supported" attribute. If an attribute is not supported, i.e.,
there is no corresponding Printer object "xxx-supported"
attribute, the Printer object flags the attribute as unsupported.
If an attribute value is not supported, i.e., there is no
corresponding value in the Printer object's "xxx-supported"
attribute, the Printer object flags the value as unsupported. If
the attribute contains more than one value, each value is checked
and each unsupported value is separately flagged as unsupported.
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9. Once all the Operation and Job Template attributes have been
checked individually, the Printer object SHOULD check for any
conflicting values among all the supported values supplied by the
client. For example, a Printer object might be able to staple
and to print on transparencies, however due to physical stapling
constraints, the Printer object might not be able to staple
transparencies. Each attribute value involved in a cross-
attribute conflict is flagged as a conflicting.
10. If there are any attributes or attribute values flagged as
unsupported or conflicting, the Printer object:
(1) copies the unsupported attributes to the Unsupported
Attributes response group and sets their value to 'unsupported'.
(2) copies the supported attributes and their unsupported
attribute values to the Unsupported Attributes response group. If
any attributes are multi-valued, only the unsupported values of
the attributes are copied.
(3) copies the supported attributes and their conflicting
attribute values to the Unsupported Attributes response group.
The Printer object only copies over those attributes that the
Printer object either ignores or substitutes in order to resolve
the conflict, and it returns the original values which were
supplied by the client. For example suppose the client supplies
"finishings" equals 'staple' and "media" equals 'transparency',
but the Printer object does not support stapling transparencies.
If the Printer chooses to ignore the stapling request in order to
resolve the conflict, the Printer objects returns "finishings"
equal to 'staple' in the Unsupported Attributes response group.
If any attributes are multi-valued, only the conflicting values
of the attributes are copied.
(4) If "ipp-attribute-fidelity" is set to 'true', the Printer
object rejects the request and returns the 'client-error-
conflicting-attributes' status code, if there were any conflicts.
Otherwise, the Printer object returns the 'client-error-
attribute-not-supported' status code.
11. If the requested operation is the Validate-Job operation,
the Printer object returns:
(1) the "successful-ok" status code, if there are no unsupported
or conflicting attributes or values.
(2) the "successful-ok-conflicting-attributes, if there are any
conflicting attribute or values.
(3) the "successful-ok-ignored-or-substituted-attributes, if
there are only unsupported attributes or values.
12. If "ipp-attribute-fidelity" is set to 'false' (or it was not
supplied by the client), the Printer object:
(1) removes all unsupported attributes from the Job object.
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(2) for each unsupported value, removes either the unsupported
value or substitutes the unsupported attribute value with some
supported value. If an attribute has no values after removing
unsupported values from it, the attribute is removed from the Job
object (so that the normal default behavior at job processing
time will take place for that attribute).
(3) for each conflicting value, removes either the conflicting
value or substitutes the conflicting attribute value with some
other supported value. If an attribute has no values after
removing conflicting values from it, the attribute is removed
from the Job object (so that the normal default behavior at job
processing time will take place for that attribute).
13. Once the Job object has been created, the Printer object
accepts the request and returns to the client:
(1) the 'successful-ok' status code, if there are no unsupported
or conflicting attributes or values.
(2) the 'successful-ok-conflicting-attributes' status code, if
there are any conflicting attribute or values.
(3) the 'successful-ok-ignored-or-substituted-attributes' status
code, if there are only unsupported attributes or values.
The Printer object also returns Job status attributes that
indicate the initial state of the Job ('pending', 'pending-held',
'processing', etc.), etc. See Print-Job Response, section
3.2.1.2.
14. The Printer object accepts the appended Document Content
data and either starts it printing, or spools it for later
processing.
15. If there were no attributes or values flagged as
unsupported, or the value of 'ipp-attribute-fidelity" was
'false', the Printer object is able to accept the create request
and create a new Job object. If the "ipp-attribute-fidelity"
attribute is set to 'true', the Job Template attributes that
populate the new Job object are necessarily all the Job Template
attributes supplied in the create request. If the "ipp-
attribute-fidelity" attribute is set to 'false', the Job Template
attributes that populate the new Job object are all the client
supplied Job Template attributes that are supported or that have
value substitution. Thus, some of the requested Job Template
attributes may not appear in the Job object because the Printer
object did not support those attributes. The attributes that
populate the Job object are persistently stored with the Job
object for that Job. A Get-Attributes operation on that Job
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object will return only those attributes that are 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 Printer objects 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.
16. 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 Job Template
attributes that the client did not supply were to be used to
populate the Job object, then 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 attribute is 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.
17. 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.
18. The Printer object uses its own configuration and
implementation specific algorithms for scheduling the Job in the
correct processing order. Once the Printer object begins
processing the Job, the Printer changes the Job's state to
'processing'. If the Printer object supports PDL override (the
"pdl-override" attribute set to 'attempted'), the implementation
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does its best to see that IPP attributes take precedence over
embedded instructions in the document data.
19. 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 'canceled' 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.
20. 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 "client-error-not-found" or "client-error-gone" status codes
for operations directed at that Job.
Some Printer object 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
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 client supplied "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
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document data has already been formatted for printing. If the
document data has been formatted, then go to 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 placed 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 a sequence of print-stream pages. This
step is controlled by the "number-up" attribute. If the value of
"number-up" is N, then during the processing of the print-stream
pages, each N print-stream pages are positioned, as specified in
section 4.2.8, to create a single impression. If a given document
does not have N more print-stream pages, then the completion of
the impression is controlled by the "multiple-document-handling"
attribute as described in section 4.2.6; when the value of this
attribute is 'single-document', the print-stream pages of
document data from subsequent documents is used to complete the
impression.
The size(scaling), position(translation) and rotation of the
print-stream pages on the impression is implementation defined.
Note that during this process the print-stream pages may be
rendered to a form suitable for placing on the impression; this
rendering is controlled by the values of the "printer-resolution"
and "print-quality" attributes as described in sections 4.2.10
and 4.2.11. In the case N=1, the impression is nearly the same as
the print-stream page; the differences would only be in the size,
position and rotation of the print-stream page and/or any
decoration, such as a frame to the page, that is added by the
implementation.
4. The collection of impressions is placed, in sequence, onto sides
of the media sheets. This placement is controlled by the "sides"
attribute and the orientation of the print-stream page, as
described in section 4.2.9. The orientation of the print-stream
pages affects the orientation of the impression; for example, if
"number-up" equals 2, then, typically, two portrait print-stream
pages become one landscape impression. Note that the placement of
impressions onto media sheets is also controlled by the
"multiple-document-handling" attribute as described in section
4.2.6.
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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
contexts, or filtered searches on attribute values of entries. For
example, a client can find all printers in the "Local Department"
context. Authentication and authorization are also often part of a
directory service so that an administrator can place limits on end
users so that they are only allowed to find entries to which they have
certain access rights. IPP itself does not require any specific
directory service protocol or provider.
Note: Some directory implementations allow for the notion of
"aliasing". That is, one directory entry object can appear as
multiple directory entry object with different names for each object.
In each case, each alias refers to the same directory entry object
which refers to a single IPP Printer object.
The generic schema is a subset of IPP Printer Job Template and Printer
Description attributes (sections 4.2 and 4.4). These attributes are
identified as either MANDATORY or OPTIONAL for the directory 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
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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-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
color-supported OPTIONAL Section 4.4.22
finishings-supported OPTIONAL Section 4.2.6
number-up-supported OPTIONAL Section 4.2.7
sides-supported OPTIONAL Section 4.2.8
media-supported OPTIONAL Section 4.2.11
printer-resolution-supported OPTIONAL Section 4.2.12
print-quality-supported OPTIONAL Section 4.2.13
document-format-supported OPTIONAL Section 4.4.18
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