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INTERNET-DRAFT draft-ietf-ipp-model-06.txt R. deBry IBM Corporation T. Hastings Xerox Corporation R. Herriot Sun Microsystems S. Isaacson Novell, Inc. P. Powell San Diego State University October 14, 1997 Internet Printing Protocol/1.0: Model and Semantics Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress". To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Abstract This document is one of a set of documents, which together describe all aspects of a new Internet Printing Protocol (IPP). IPP is an application level protocol that can be used for distributed printing using Internet tools and technology. The protocol is heavily influenced by the printing model introduced in the Document Printing Application (DPA) [ISO10175] standard. Although DPA specifies both end user and administrative features, IPP version 1.0 is focused only on end user functionality. deBry, Hastings, Herriot, Isaacson, Powell [Page 1] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 The full set of IPP documents includes: Requirements for an Internet Printing Protocol [IPP-REQ] Internet Printing Protocol/1.0: Model and Semantics Internet Printing Protocol/1.0: Protocol Specification [IPP-PRO] Rationale for the Structure and Model and Protocol for the Internet Printing Protocol [IPP-RAT] The requirements document, "Requirements for an Internet Printing Protocol", takes a broad look at distributed printing functionality, and it enumerates real-life scenarios that help to clarify the features that need to be included in a printing protocol for the Internet. It identifies requirements for three types of users: end users, operators, and administrators. The requirements document calls out a subset of end user requirements that MUST be satisfied in the first version of IPP. Operator and administrator requirements are out of scope for v1.0. This document, "Internet Printing Protocol/1.0: Model and Semantics", describes a simplified model with abstract objects, their attributes, and their operations. The model introduces a Printer object and a Job object. The Job object supports multiple documents per job. The model document also addresses how security, internationalization, and directory issues are addressed. The protocol specification, " Internet Printing Protocol/1.0: Protocol Specification", is a formal mapping of the abstract operations and attributes defined in the model document onto HTTP/1.1. The protocol specification defines the encoding rules for a new Internet media type called "application/ipp". deBry, Hastings, Herriot, Isaacson, Powell [Page 2] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Table of Contents 1. Simplified Printing Model .......................................8 2. IPP Objects ....................................................10 2.1 Printer Object................................................10 2.2 Job Object....................................................13 2.3 Object Relationships..........................................14 2.4 Object Identity...............................................14 3. IPP Operations .................................................15 3.1 General Semantics.............................................16 3.1.1 Operation Characteristics................................16 3.1.2 Operation Targets........................................18 3.1.3 Character Set and Natural Language Operation Attributes..19 3.1.3.1 Request Operation Attributes ..........................19 3.1.3.2 Response Operation Attributes .........................20 3.1.4 Operation Status Codes and Messages......................21 3.1.5 Security Concerns for IPP Operations.....................22 3.1.5.1 Authenticated Requester Identity ......................22 3.1.5.2 Restricted Queries ....................................23 3.1.6 Versions.................................................23 3.1.7 Job Creation Operations..................................24 3.2 Printer Operations............................................26 3.2.1 Print-Job Operation......................................26 3.2.1.1 Print-Job Request .....................................26 3.2.1.2 Print-Job Response ....................................28 3.2.2 Print-URI Operation......................................30 3.2.3 Validate-Job Operation...................................31 3.2.4 Create-Job Operation.....................................31 3.2.5 Get-Attributes Operation.................................31 3.2.5.1 Get-Attributes Request ................................32 3.2.5.2 Get-Attributes Response ...............................33 3.2.6 Get-Jobs Operation.......................................34 3.2.6.1 Get-Jobs Request ......................................34 3.2.6.2 Get-Jobs Response .....................................35 3.3 Job Operations................................................36 3.3.1 Send-Document Operation..................................37 3.3.1.1 Send-Document Request .................................37 3.3.1.2 Send-Document Response ................................39 3.3.2 Send-URI Operation.......................................39 3.3.3 Cancel Job Operation.....................................39 3.3.3.1 Cancel-Job Request ....................................40 3.3.3.2 Cancel-Job Response ...................................40 3.3.4 Get-Attributes Operation.................................41 3.3.4.1 Get-Attributes Request ................................41 3.3.4.2 Get-Attributes Response ...............................41 4. Object Attributes ..............................................42 4.1 Attribute Syntaxes............................................42 4.1.1 'text'...................................................43 deBry, Hastings, Herriot, Isaacson, Powell [Page 3] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.1.2 'name'...................................................44 4.1.3 'keyword'................................................44 4.1.4 'enum'...................................................45 4.1.5 'uri'....................................................45 4.1.6 'uriScheme'..............................................45 4.1.7 'charSet'................................................46 4.1.8 'naturalLanguage'........................................46 4.1.9 'mimeType'...............................................47 4.1.10 'octetString'............................................48 4.1.11 'boolean'................................................48 4.1.12 'integer'................................................48 4.1.13 'rangeOfInteger'.........................................48 4.1.14 'dateTime'...............................................48 4.1.15 'resolution'.............................................48 4.1.16 '1setOf X'..............................................49 4.2 Job Template Attributes.......................................49 4.2.1 job-sheets (type4 keyword, name).........................53 4.2.2 job-priority (integer(1:100))............................54 4.2.3 job-hold-until (type4 keyword, name).....................55 4.2.4 multiple-document-handling (type2 keyword)...............56 4.2.5 media (type4 keyword, name)..............................57 4.2.6 number-up (integer)......................................57 4.2.7 sides (type2 keyword)....................................58 4.2.8 printer-resolution (resolution)..........................59 4.2.9 print-quality (type2 enum)...............................59 4.2.10 finishings (1setOf type2 enum)...........................59 4.2.11 copies (integer(1:2**31 - 1))............................60 4.2.12 page-ranges (1setOf rangeOfInteger)......................60 4.2.13 orientation (type2 enum).................................61 4.2.14 document-format (mimeType)...............................61 4.2.15 compression (type3 keyword)..............................62 4.2.16 job-k-octets (integer(0:2**31 - 1))......................62 4.2.17 job-impressions (integer(0:2**31 - 1))...................62 4.2.18 job-media-sheets (integer(0:2**31 - 1))..................63 4.3 Job Description Attributes....................................63 4.3.1 job-uri (uri)............................................64 4.3.2 job-id (integer(1:MAX))..................................65 4.3.3 job-more-info (uri)......................................65 4.3.4 job-name (name)..........................................65 4.3.5 job-originating-user (octetString).......................65 4.3.6 job-state (type1 enum)...................................66 4.3.7 job-state-reasons (1setOf type2 keyword)................68 4.3.8 job-state-message (text).................................70 4.3.9 number-of-documents (integer(0:2**31 - 1))...............70 4.3.10 output-device-assigned (name)............................71 4.3.11 time-of-creation (integer)...............................71 4.3.12 time-at-processing (integer).............................71 4.3.13 time-at-completed (integer)..............................71 deBry, Hastings, Herriot, Isaacson, Powell [Page 4] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.3.14 number-of-intervening-jobs (integer(0:2**31 - 1))........71 4.3.15 job-message-from-operator (text).........................71 4.3.16 job-k-octets-processed (integer(0:2**31 - 1))............72 4.3.17 job-impressions-completed (integer(0:2**31 - 1))........72 4.3.18 job-media-sheets-completed (integer(0:2**31 - 1))........72 4.3.19 attributes-charset (charSet).............................72 4.3.20 attributes-natural-language (naturalLanguage)............73 4.4 Printer Description Attributes................................73 4.4.1 printer-uri (uri)........................................75 4.4.2 printer-name (name)......................................75 4.4.3 printer-location (text)..................................75 4.4.4 printer-info (text)......................................75 4.4.5 printer-more-info (uri)..................................75 4.4.6 printer-driver-installer (uri)...........................76 4.4.7 printer-make-and-model (text)............................76 4.4.8 printer-more-info-manufacturer (uri).....................76 4.4.9 printer-state (type1 enum)...............................76 4.4.10 printer-state-reasons (1setOf type2 keyword).............77 4.4.11 printer-state-message (text).............................80 4.4.12 operations-supported (1setOf operation)..................80 4.4.13 printer-charset (charSet)................................81 4.4.14 charsets-supported (1setOf charSet)......................81 4.4.15 printer-natural-language (naturalLanguage)...............81 4.4.16 natural-languages-supported (1setOf naturalLanguage).....81 4.4.17 printer-is-accepting-jobs (boolean)......................82 4.4.18 queued-job-count (integer(0:2**31 - 1))..................82 4.4.19 printer-message-from-operator (text).....................82 4.4.20 color-supported (boolean)................................82 4.4.21 reference-uri-schemes-supported (1setOf uriScheme).......83 4.4.22 pdl-override (type2 keyword).............................83 4.4.23 security-mechanisms-supported (1setOf keyword)...........83 4.4.24 printer-up-time (integer(1:MAX)).........................84 4.4.25 printer-current-time (dateTime)..........................84 4.4.26 multiple-operation-time-out (integer)....................84 5. Conformance ....................................................84 5.1 Client Conformance Requirements...............................85 5.2 Printer Object Conformance Requirements.......................85 5.2.1 Objects..................................................86 5.2.2 Operations...............................................86 5.2.3 Attributes...............................................86 5.2.4 Printer extensions.......................................87 5.2.5 Attribute Syntaxes.......................................87 5.3 Security Conformance Requirements.............................87 6. IANA Considerations (registered and private extensions) ........87 6.1 Typed Extensions..............................................88 6.2 Registration of MIME types/sub-types for document-formats.....89 6.3 Attribute Extensibility.......................................89 6.4 Attribute Syntax Extensibility................................89 deBry, Hastings, Herriot, Isaacson, Powell [Page 5] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 7. Internationalization Considerations ............................89 8. Security Considerations ........................................91 8.1 Client and Printer in the Same Security Domain................92 8.2 Client and Printer in Different Security Domains..............92 8.3 Print by Reference............................................93 8.3.1 Unprotected Documents....................................93 8.3.2 Protected Documents......................................93 8.4 Common Security Scenarios.....................................93 8.4.1 No Security..............................................93 8.4.2 Message Protection During Transmission...................94 8.4.3 Client Authentication and Authorization..................94 8.4.4 Mutual Authentication, Authorization and Message Protection 94 8.5 Recommended Security Mechanisms...............................94 9. References .....................................................95 10.Copyright Notice ...............................................99 11.Author's Address ...............................................99 12.APPENDIX A: Terminology .......................................102 12.1 Conformance Terminology......................................102 12.1.1 MUST....................................................102 12.1.2 MUST NOT................................................102 12.1.3 SHOULD..................................................102 12.1.4 SHOULD NOT..............................................102 12.1.5 MAY.....................................................102 12.1.6 NEED NOT................................................103 12.2 Model Terminology............................................103 12.2.1 Keyword.................................................103 12.2.2 Attributes..............................................103 12.2.2.1 Attribute Name .......................................103 12.2.2.2 Attribute Group Name .................................104 12.2.2.3 Attribute Value ......................................104 12.2.2.4 Attribute Syntax .....................................104 12.2.3 Supports................................................104 12.2.4 print-stream page.......................................106 12.2.5 imposed page............................................106 13.APPENDIX B: Status Codes .....................................106 13.1 Status Codes.................................................107 13.1.1 Informational...........................................107 13.1.2 Successful Status Codes.................................107 13.1.2.1 successful-ok (0x0000) ...............................107 13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001) 108 13.1.3 Redirection Status Codes................................108 13.1.4 Client Error Status Codes...............................108 13.1.4.1 client-error-bad-request (0x0400) ....................108 13.1.4.2 client-error-forbidden (0x0401) ......................108 13.1.4.3 client-error-not-authenticated (0x0402) ..............108 13.1.4.4 client-error-not-authorized (0x0403) .................109 deBry, Hastings, Herriot, Isaacson, Powell [Page 6] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.1.4.5 client-error-not-possible (0x0404) ...................109 13.1.4.6 client-error-timeout (0x0405) ........................109 13.1.4.7 client-error-not-found (0x0406) ......................109 13.1.4.8 client-error-gone (0x0407) ...........................110 13.1.4.9 client-error-request-entity-too-large (0x0408) .......110 13.1.4.10 client-error-request-URI-too-long (0x0409) ...........110 13.1.4.11 client-error-unsupported-document-format (0x040A) ....110 13.1.4.12 client-error-attribute-not-supported (0x040B) ........111 13.1.4.13 client-error-uri-scheme-not-supported (0x040C) .......111 13.1.4.14 client-error-charset-not-supported (0x040D) ..........111 13.1.4.15 client-error-natural-language-not-supported (0x040E) .111 13.1.5 Server Error Status Codes...............................111 13.1.5.1 server-error-internal- error (0x0500) ................112 13.1.5.2 server-error-operation-not-supported (0x0501) ........112 13.1.5.3 server-error-service-unavailable (0x0502) ............112 13.1.5.4 server-error-version-not-supported (0x0503) ..........112 13.1.5.5 server-error-device-error (0x0504) ...................112 13.1.5.6 server-error-temporary-error (0x0505) ................113 13.2 Status Codes for IPP Operations..............................114 14.APPENDIX C: "media" keyword values ...........................114 15.APPENDIX D: Processing IPP Attributes .........................119 15.1 Fidelity.....................................................119 15.2 Page Description Language (PDL) Override.....................121 15.3 Suggested Operation Processing Algorithm.....................122 15.4 Using Job Template Attributes During Document Processing.....126 16.APPENDIX E: Generic Directory Schema ..........................127 deBry, Hastings, Herriot, Isaacson, Powell [Page 7] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 1. Simplified Printing Model In order to achieve its goal of realizing a workable printing protocol for the Internet, the Internet Printing Protocol (IPP) is based on a simplified printing model that abstracts the many components of real world printing solutions. The Internet is a distributed computing environment where requesters of print services (clients, applications, printer drivers, etc.) cooperate and interact with print service providers. This model and semantics document describes a simple, abstract model for IPP even though the underlying configurations may be complex "n-tier" client/server systems. An important simplifying step in the IPP model is to expose only the key objects and interfaces required for printing. The model does not include features, interfaces, and relationships that are beyond the scope of IPP/1.0. IPP incorporates many of the relevant ideas and lessons learned from other specification and development efforts [HTPP] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP]. The IPP model encapsulates the important components of distributed printing into two object types: - Printer (Section 2.1) - Job (Section 2.2) Each object type has an associated set of operations (see section 3) and attributes (see section 4). The terminology used in the remainder of this document is defined in (section 12). In the remainder of this document, terms such as "attributes", "keywords", and "supports" have special meaning and are defined in the model terminology section. Capitalized terms such as MANDATORY, SHALL, and OPTIONAL have special meaning relating to conformance. These terms are defined in the section on conformance terminology, most of which is taken from RFC 2119 [RFC2119]. It is important, however, to understand that in real system implementations (which lie underneath the abstracted IPP model), there are other components of a print service which are not explicitly defined in the IPP model. The following figure illustrates where IPP fits with respect to these other components. deBry, Hastings, Herriot, Isaacson, Powell [Page 8] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 +--------------+ | Application | o +. . . . . . . | \|/ | Spooler | / \ +. . . . . . . | +---------+ End-User | Print Driver |---| File | +-----------+ +-----+ +------+-------+ +----+----+ | Browser | | GUI | | | +-----+-----+ +--+--+ | | | | | | | +---+------------+---+ | N D S | | IPP Client |------------+ O I E | +---------+----------+ T R C | | I E U | F C R -------------- Transport ------------------ I T I C O T | --+ A R Y +--------+--------+ | T Y | IPP Server | | I +--------+--------+ | O | | N +-----------------+ | IPP Printer | Print Service | | +-----------------+ | | --+ +-----------------+ | Output Device(s)| +-----------------+ An IPP Printer encapsulates the functions normally associated with physical output devices along with the spooling, scheduling and multiple device management functions often associated with a print server. IPP Printers are optionally registered as entries in a directory where end users find and select them based on some sort of filtered and context based searching mechanism. The directory is used to store relatively static information about the Printer, allowing end users to search for and find Printers that match their search criteria, for example: name, context, printer capabilities, etc. (see section 16). The more dynamic information is directly associated with the IPP Printer itself. This information includes state, currently loaded and ready media, number of jobs at the Printer, errors, warnings, and so forth. IPP Clients implement the IPP protocol on the client side, and give end users (or programs) the ability to query an IPP Printer and submit and manage print jobs. An IPP server is just that part of the IPP deBry, Hastings, Herriot, Isaacson, Powell [Page 9] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Printer that implements the server-side protocol. The rest of the IPP Printer implements the application semantics of the print service itself. The IPP Printer may be embedded in an output device or may be implemented on a host on the network that communicates with the output device. When a job is submitted to the Printer object and the Printer object validates the attributes in the submission request, the Printer object creates a new Job object. The end user then interacts with this new Job object to query its status and monitor the progress of the job. End users may also cancel print job by using the Job object's Cancel- Job operation. The end user is able to register to receive certain events that are then routed using the specified notification service(s). 2. IPP Objects The IPP model introduces objects of type Printer and Job. Each type of object models relevant aspects of a real-world entity such as a real printer or print job. Each object type is defined as a set of possible attributes that may be supported by instances of that object type. For each object, the actual set of supported attributes and values describe a specific implementation. The object's attributes and values describe its state, capabilities, realizable features, job processing functions, and default behaviors and characteristics. For example, the object type Printer is defined as a set of attributes that each Printer object potentially supports. In the same manner, the object type Job is defined as a set of attributes that are potentially supported by each Job object. Each attribute included in the set of attributes defining an object type is labeled as: - "MANDATORY": each object SHALL support the attribute. - "OPTIONAL": each object OPTIONALLY supports the attribute. There is no such similar labeling of attribute values. However, if an implementation supports an attribute, it MUST support at least one of the possible values for that attribute. 2.1 Printer Object A major component of the IPP model is the Printer object (also called the IPP Printer). A Printer object implements the IPP protocol. Using the protocol, end users may query the attributes of the Printer and submit Jobs to the Printer. The actual implementation components deBry, Hastings, Herriot, Isaacson, Powell [Page 10] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 behind the Printer abstraction may take on different forms and different configurations. However, the model abstraction allows the details of the configuration of real components to remain opaque to the end user. Section 3 describes each of the Printer operations in detail. The capabilities and state of a Printer object are described by its attributes. Printer attributes are grouped into two groups: - "job-template" attributes: These attributes the describe job processing capabilities and defaults for the Printer object. (See section 4.2) - "printer-description" attributes: These attributes describe the Printer object's identification, state, location, references to other sources of information about the Printer object, etc. (see section 4.4) Since a Printer object is an abstraction of a generic document output device and print service provider, a Printer object could be used to represent any real or virtual device with semantics consistent with the Printer object, such as a fax device, an imager, or even a CD writer. Some examples of configurations supporting a Printer object include: 1) An output device, with no spooling capabilities 2) An output device, with a built-in spooler 3) A print server supporting IPP with one or more associated output devices 3a) The associated output devices might or might not be capable of spooling jobs 3b) The associated output devices might or might not support IPP The following figures show some examples of how Printer objects can be realized on top of various distributed printing configurations. The embedded case below represents configurations 1 and 2. The hosted and fan-out figures below represent configuration 3. deBry, Hastings, Herriot, Isaacson, Powell [Page 11] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Legend: ##### indicates a Printer object which is either embedded in an output device or is hosted in a server. The implementation might or might not be capable of queuing/spooling. any indicates any network protocol or direct connect, including IPP embedded printer: output device +---------------+ O +--------+ | ########### | /|\ | client |------------IPP------------># Printer # | / \ +--------+ | # Object # | | ########### | +---------------+ hosted printer: +---------------+ O +--------+ ########### | | /|\ | client |--IPP--># Printer #-any->| output device | / \ +--------+ # Object # | | ########### +---------------+ +---------------+ fan out: | | +-->| output device | any/ | | O +--------+ ########### / +---------------+ /|\ | client |-IPP-># Printer #--* / \ +--------+ # Object # \ +---------------+ ########### any\ | | +-->| output device | | | +---------------+ A Printer object is identified with a Uniform Resource Identifier (URI) [RFC1630]. Often, the URI is a Uniform Resource Locator (URL) [RFC1738] [RFC1808].. deBry, Hastings, Herriot, Isaacson, Powell [Page 12] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Note: The IPP protocol specification [IPP-PRO] defines a mapping of IPP onto HTTP/1.1. Therefore, all conforming Printer objects SHALL support HTTP schemed URIs to identify themselves. For example, a Printer object's URI could be "http://www.some-domain.org/printer- one". A Printer object's URI could not be "ftp://ftp.some- domain.org/printer-one". IPP does not specify how the URI is obtained, but it is RECOMMENDED that a Printer object is registered in a directory service which end users and programs can interrogate. Section 16 defines a generic schema for Printer object entries in the directory service. 2.2 Job Object A Job object is used to model a print job. A Job can contain one or more documents. The information required to create a Job object is sent in a create request from the end user via an IPP Client to the Printer object. Section 3 describes each of the Job operations in detail. The characteristics and state of a Job object are described by its attributes. Job attributes are grouped into two groups as follows: - "job-template" attributes: These attributes are optionally supplied by the client or end user and include job processing instructions which are intended to override any Printer object defaults and/or instructions embedded within the document data. (See section 4.2) - "job-description" attributes: These attributes describe the Job object's identification, state, size, etc. The client does not supply values for these attributes, they are set by the Printer object. (See section 4.3) A Job object contains at least one document, but may contain multiple documents. A document consists of either: - a stream of data in a format supported by the Printer object, or - a URI reference to a stream of data in a format supported by the Printer A document is not modeled as an IPP object, therefore it has no object identifier or associated attributes. All job processing instructions are modeled as Job object attributes. These attributes are called Job Template attributes and they apply equally to all documents within a Job. deBry, Hastings, Herriot, Isaacson, Powell [Page 13] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 2.3 Object Relationships IPP objects have relationships that MUST be maintained persistently along with the persistent storage of the object attributes. A Printer object may represent one or more output devices. A Printer object may represent a logical device which "processes" jobs but never actually uses a physical output device to put marks on paper (for example a Web page publisher or an interface into an online document archive or repository). A Printer object contains zero or more Job objects. A Job object is contained by exactly one Printer object, however the identical document data associated with a Job object could be sent to either the same or a different Printer object. In this case, a new Job object would be created which would be almost identical to the existing Job object, however it would have a new (different) Job object identifier. A Job object contains one or more documents. If the contained document is a stream of printer-ready data, that stream can be contained in only one document. However, there can be copies of the stream in other documents in the same or different Job objects. If the contained document is a reference to a stream of printer-ready data, other documents (in the same or different Job object(s)) may reference the same stream. 2.4 Object Identity All Printer and Job objects have an identifier so that they can be persistently and unambiguously referenced. The IPP model requires that these identifiers be URIs. Often, the URI is a URL [RFC1738] [RFC1808]. Allowing Job objects to have URIs allows for flexibility and scalability. In some implementations, the Printer object might create Jobs that are processed in the same local environment as the Printer object itself. In this case, the Job URI might just be a composition of the Printer's URI and some unique component for the Job object. In other implementations, the Printer object might be a central clearing- house for validating all Job object creation requests, and the Job object itself might be created in some environment that is remote from the Printer object. In this case, the Job object's URI may have no relationship at all to the Printer object's URI. However, many existing printing systems have local models or interface constraints that force Job objects to be identified using only a 32- bit positive integer rather than a URI. This numeric Job ID is only unique within the context of the Printer object to which the create request was originally submitted. In order to allow both types of client access to Jobs (either Job URI or numeric Job ID), when the Printer object successfully processes a create request and creates a deBry, Hastings, Herriot, Isaacson, Powell [Page 14] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 new Job, the Printer object SHALL generate both a Job URI and a Job ID for the new Job object. This requirement allows all clients to access Printer objects and Job objects no matter the local constraints imposed on the client implementation. In addition to a unique identifier, Printer objects and Job objects may have names. An object name need not be unique across all instances of all objects. A Printer object's name is chosen and set by an administrator through some mechanism outside the scope of IPP. A Job object's name is optionally chosen and supplied by the IPP Client submitting the job. If the client does not supply a Job object name, the Printer object generates a name for the new Job object. In all cases, the name only has local meaning, and it is not constrained to be unique. To summarize: - Each Printer object is uniquely identified with a URI. The Printer's "printer-uri" attribute contains the URI. - Each Job object is uniquely identified with a URI. The Job's "job-uri" attribute contains the URI. - Each Job object is also uniquely identified with a combination of the URI of the Printer object to which the create request was originally submitted along with a Job ID (a 32-bit, positive number) that is unique within the context of that Printer object. The Printer object's "printer-uri" contains the Printer URI. The Job object's "job-id" attribute contains the numeric Job ID. - Each Printer object has a name (which is not necessarily unique). The administrator chooses and sets this name through some mechanism outside the scope of IPP itself. The Printer object's "printer-name" attribute contains the name. - Each Job object has a name (which is not necessarily unique). The client optionally supplies this name in the create request. If the client does not supply this name, the Printer object generates a name for the Job object. The Job object's "job-name" attribute contains the name. 3. IPP Operations IPP objects have associated operations. An operation consists of a request and a response. When a client communicates with an IPP object, it issues an operation request to the URI for that object. Operations have attributes that supply information about the operation itself. These attributes are called operation attributes (as compared to object attributes such as Printer attributes or Job attributes). Each request carries along with it any operation attributes and/or document data required by the object to perform the operation. Each deBry, Hastings, Herriot, Isaacson, Powell [Page 15] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 request requires a response from the object. Each response indicates success or failure of the operation with a status code. The response contains any operation attributes, object attributes, and/or status messages generated by the execution of the operation request. This section describes the semantics of the IPP operations, both requests and responses, in terms of the attributes and other data associated with each operation. Note: The IPP protocol specification [IPP-PRO] describes a mapping and encoding of IPP operations onto HTTP/1.1 POST commands. Other mappings for IPP operations to additional transport mechanisms are possible. The Printer operations are: Print-Job (section 3.2.1) Print-URI (section 3.2.2) Validate-Job (section 3.2.3) Create-Job (section 3.2.4) Get-Attributes (section 3.2.5) Get-Jobs (section 3.2.6) The Job operations are: Send-Document (section 3.3.1) Send-URI (section 3.3.2) Cancel-Job (section 3.3.3) Get-Attributes (section 3.3.4) The Send-Document and Send-URI Job operations are used to add a new document to an existing multi-document Job object created with the Create-Job operation. 3.1 General Semantics 3.1.1 Operation Characteristics Each IPP operation is defined as both a request and a response. Both requests and responses are composed of groups of attributes and/or document data. Attributes are grouped into the following groups: - Operation Attributes: These are attributes that are only passed in the operation itself, and usually do not persist beyond the life of the operation. Operation attributes may also affect other attributes or groups of attributes since values in the operation attributes usually affect the behavior of the object deBry, Hastings, Herriot, Isaacson, Powell [Page 16] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 that processes the operation. All IPP objects that accept IPP operation request MUST support all operation attributes. Some operation attributes are OPTIONAL for the client to supply, but the IPP object MUST support the attribute by being prepare to handle the client supplied operation attribute by realizing the corresponding feature or function. - Job Template Attributes: These attributes affect the processing of a job. They are OPTIONALLY supplied by a client in a create request, and the receiving object MUST be prepared to received all supported attributes. The Job object can later be queried to find out what was originally requested in the create request. The Printer object can be queried to find out what type of job processing capabilities are supported and/or what the default job processing behaviors are. - Job Object Attributes: These attributes are returned in response to query operation directed at a Job object. - Printer Object Attributes: These attributes are returned in response to a query operation directed at a Printer object. - Unsupported Attributes: In a create request, the client supplies an optional set of Job Template attributes. If any of these are unsupported by the Printer object, the Printer object returns them in the response. Section 15 gives a full description of how Job Template attributes supplied by the client in a create request are processed by the Printer object and how unsupported attributes are returned to the client. Later in this section, each operation is formally defined by identifying the allowed and expected groups of attributes for request and response. The model identifies a specific order for each group in each request or response, but the attributes within each group may be in any order. Note: Document data included in the operation is not strictly an attribute, but it is treated as a special attribute group for ordering purposes. The only operations that support supplying the document data within an operation request are Print-Job and Send-Document. There are no operations responses that include document data. Since some operations are MANDATORY and some are OPTIONAL, a client SHOULD first use the MANDATORY Get-Attributes operation to query the Printer's "operations-supported" attribute before using any unsupported operation. A client SHOULD NOT attempt to use an unsupported operation. When a Printer object receives a request to perform an operation it does not support, it returns the error code 'server-error-operation-not-supported' (see section 13.1.5.2). deBry, Hastings, Herriot, Isaacson, Powell [Page 17] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 3.1.2 Operation Targets All IPP operations are directed at IPP objects. For Printer operations, the operation is always directed at a Printer object using its URI (the "printer-uri" attribute). For Job operations, the operation is directed at either: - the Job object itself using the Job object's URI ("job-uri") assigned by the Printer object, or - the Printer object to which the job was originally submitted using the URI of the Printer ("printer-uri") in combination with and the 32-bit numeric Job ID ("job-id") assigned by the Printer object. If the operation is directed at the Job object directly using the Job object's URI, the client SHOULD NOT include the redundant "job-id" operation attribute. Note: In the mapping of IPP over HTTP/1.1, the object's URI is actually encoded as the "request-URI" field of the HTTP POST operation. In the case of Printer operations directed at a Printer object, the Printer object's "printer-uri" attribute is mapped to the "request-URI" attribute in the HTTP header. In the case of Job operations directed at the Job object, the Job object's "job-uri" attribute is mapped to the "request-URI" attribute in the HTTP header. In the case of Job operations directed at the Printer object that created the Job, the Printer object's "printer-uri" attribute is sent in the HTTP header, and the "job-id" attribute is sent as an operational attribute in the request body. In other mappings of IPP operations onto some other transport mechanism, the target URI is encoded using some other transport specific addressing mechanism. The following rules apply to the use of port numbers in URIs that identify IPP objects: 1. If the protocol scheme for the URI allows the port number to be explicitly included in the URI string, and an explicit port number is specified in the published URI, then that port number MUST be used by the client to contact the IPP server. 2. If the protocol scheme for the URI does not allow an explicit port number specification, then the default port number for the protocol should be used. 3. Consult the appropriate IPP protocol mapping document to determine alternate port numbers for the protocol specified in the server URI. deBry, Hastings, Herriot, Isaacson, Powell [Page 18] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 3.1.3 Character Set and Natural Language Operation Attributes Some Job and Printer attributes have values that are text strings and names intended for human understanding rather than machine understanding (see the 'text' and 'name' attribute syntax descriptions in section 4.1). The following sections describe two MANDATORY attributes for every IPP operation request and response. These attributes are "attributes-charset" and "attributes-natural-language". For the sake of brevity in this document, these operation attribute descriptions are not repeated with every operation request and response, but have a reference back to this section instead. 3.1.3.1 Request Operation Attributes The client SHALL supply and the Printer object SHALL support the following MANDATORY operation attributes in every IPP operation request: "attributes-charset" (charSet): This operation attribute identifies the charset (coded character set and encoding method) used by any 'text' and 'name' attributes that the client is supplying in this request and that the Printer object SHALL return in this operation response. See Sections 4.1.1 and 4.1.2 for the specification of the 'text' and 'name' attribute syntaxes. The Printer object SHALL support the 'utf-8' charset [RFC2044] and MAY support additional charsets provided that they are registered with IANA [IANA-CS]. If the Printer object does not support the supplied charset value, the Printer object SHALL reject the request and return status code 'client-error-charset- not-supported'. The Printer object SHALL indicate the charset(s) supported as the values of the "charsets-supported" Printer attribute (see Section 4.4.14), so that the client MAY query which charset(s) are supported. See the 'charSet' attribute syntax description in Section 4.1.7 for the syntax and semantic interpretation of the values of this attribute and for example values. "attributes-natural-language" (naturalLanguage): This operation attribute identifies the natural language used by any 'text' and 'name' attributes that the client is supplying in this request. A Printer SHOULD do its best to respond in the same natural language. deBry, Hastings, Herriot, Isaacson, Powell [Page 19] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 There are no MANDATORY natural languages required for the Printer object to support. However, the Printer's "natural-language- supported" attribute SHALL list the natural languages supported, so that the client MAY query which natural language(s) are supported. For any of the attributes for which the Printer generates messages, i.e., for the "job-state-message", "printer- state-message" attributes ", and Status Messages (see Section 3.1.4) in operation responses, the Printer object SHALL be able to generate messages in any of its supported natural languages. If the client requests a natural language that is not supported, the Printer object SHALL return these generated messages in the Printer's configured natural language as specified by the Printer's "printer-natural-language " attribute" (see Section 4.4.15). For other Printer 'text' and 'name' attributes supplied by the operator, system administrator, or manufacturer, i.e., for "printer-name" (name), "printer-location" (text), "printer-info" (text), and "printer-make-and-model" (text), the Printer object is only required to support the configured natural language of the Printer identified by the Printer's "printer-natural-language " attribute, though support of additional natural languages for these attributes is permitted If the Printer object does not support the natural language value supplied by the client, the Printer object SHALL either (1) reject the request and return status code ' client-error-natural- language-not-supported' or (2) accept the natural language rather than returning an error, depending on implementation. In the latter case, the Printer object SHALL use the method for representing exception natural languages in attribute values as described for the 'text' attribute syntax in Section 4.1.1 for any such 'text' or 'name' attributes that the Printer (1) accepts from or (2) returns to a client. See the 'naturalLanguage' attribute syntax description in Section 4.1.8 for the syntax and semantic interpretation of the values of this attribute and for example values. 3.1.3.2 Response Operation Attributes The Printer object SHALL supply and the client SHALL support the following MANDATORY operation attributes in every IPP operation response: "attributescharset" (charSet): This operation attribute identifies the charset used by any 'text' and 'name' attributes that the Printer object is returning deBry, Hastings, Herriot, Isaacson, Powell [Page 20] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 in this response. The value in this response SHALL be the same value as the "attributes-charset" operation attribute supplied by the client in the request. See "attributes-charset" described in Section 3.1.3.1 above. If the Printer object supports more than just the 'utf-8' charset, the Printer object SHALL be able to code convert between each of the charsets supported on a highest fidelity possible basis in order to return the 'text' and 'name' attributes in the charset requested by the client. However, some information loss MAY occur during the charset conversion depending on the charsets involved. For example, the Printer object may convert from a UTF-8 'a' to a US-ASCII 'a' (with no loss of information), from an ISO Latin 1 CAPITAL LETTER A WITH ACUTE ACCENT to US-ASCII 'A' (losing the accent), or from a UTF-8 Japanese Kanji character to some ISO Latin 1 error character indication such as '?', decimal code equivalent, or to the absence of a character, depending on implementation. "attributes-natural-language" (naturalLanguage): This is a MANDATORY Job Template attribute for the Printer object to return. This attribute specifies the natural language used by 'text' and 'name' attributes with empty tags in this response and SHALL be the same value as supplied by the client in the request, whether the Printer object supports that value or not. Any 'text' or 'name' values in this response that have a different natural language SHALL have a fully specified natural language tag pre-pended to each such attribute value. In a subsequent query request (Get-Attributes or Get-Jobs), the Printer object NEED NOT convert any 'text' or 'name' attribute values to the natural language of the requester when it is different from that specified (and subsequently stored) in the original create request.. In such cases, the Printer object SHALL return an explicit natural language indicator for each such attribute value. See the 'text' attribute syntax description in Section 4.1.1. 3.1.4 Operation Status Codes and Messages Every operation response returns a MANDATORY status code and an OPTIONAL status message. A status code provides information on the processing of a request. A status message provides a short textual description of the status of the operation. The status code is intended for use by automata and the status message is intended for the human user. If a response does include a status message, an IPP client is not required to examine or display the status message, however it SHOULD do so in some implementation specific manner. deBry, Hastings, Herriot, Isaacson, Powell [Page 21] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Section 13 describes the status codes and suggests a corresponding status message for each status code. In some cases, if the status code indicates an error, there may be additional attributes in the response that are not returned in the successful case. One such example is the set of unsupported attributes in the Print-Job response (see section 3.2.1.2). The status code is a numeric value that has semantic meaning. The status code is similar to a "type2 enum" (see section 4.1 on "Attribute Syntaxes") except that values can range only from 0x0000 to 0xFFFF. A client implementation of IPP could convert status code values into any localized string that has semantic meaning to the end user. The Printer object SHALL be able to generate this message in any of the natural languages identified by the Printer's "natural-language- supported" attribute (see the "attributes-natural-language" operation attribute specified in Section 3.1.3.1). If the charset requested by the client in the "attributes-charset" operation attribute is not supported by the Printer object, the Printer object SHALL represent the status message, if returned, in the charset specified by the Printer's "printer-charset" attribute (which the client MAY not be able to interpret). 3.1.5 Security Concerns for IPP Operations 3.1.5.1 Authenticated Requester Identity IPP is layered on top of security services that supply the requester's identity. It is assumed that the identity supplied by the authentication service is the most authenticated identity required by a given site's configuration and current policy. It is also assumed that the layering allows for a single IPP implementation to be run over a consistent interface that supplies the authenticated identity. The authentication interface should allow for various modular and extensible authentication service implementations without requiring changes to the IPP implementation. Once the authenticated identity of the requester has been supplied to the IPP implementation, the implementation uses that identity to enforce any authorization policy(ies) that might be in place. When a Job is created, the identity of the requester from the create request is persistently stored in the Job's "job-originating-user" attribute. This attribute can be used to match the requester's identity of subsequent operations on that Job in order to enforce the local authorization policy(ies), if any. For example, a one site's policy might be that only the job owner is allowed to cancel a job. There are operation status codes that allow an implementation to return deBry, Hastings, Herriot, Isaacson, Powell [Page 22] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 information back to the operation requester about what has been forbidden, not allowed, or not authorized. The details of and mechanisms to set up authorization policy(ies) are not part of IPP, and must be established via some mechanism outside the scope of IPP. 3.1.5.2 Restricted Queries In many of these IPP operations, a client supplies a list of attributes to be returned in the response. A Printer may be configured, for security reasons, not to return all attributes that a client requests. It may even return none of the requested attributes. In such cases, the status returned is the same as if the Printer had returned all requested attributes. The client cannot tell by such a response whether the requested attribute was present or absent on the Printer or Job. 3.1.6 Versions Each operation request carries with it a version number. Each version number is in the form "X.Y" where X is the major version number and Y is the minor version number. By including a version number in the client request, it allows the client (the requester) to identify which version of IPP it is interested in using. If the Printer does not support that version, the Printer responds with a status code of 'server-error-version-not-supported'. There is no version negotiation per se. However, if after receiving a version not supported status code from the Printer, there is nothing that prevents a client from trying again with a different version number. For example, a client might be configured to support IPP version 3.0, 2.5, 2.0 and 1.0 (hypothetically speaking). A client might first try to speak version 3.0. If after receiving a version not supported, it might successively try version 2.5, then 2.0, and then 1.0. All implementations MUST support version 1.0. There is only one version number that covers both IPP Model and the IPP Protocol changes. Thus the version number MUST change when introducing a new version of the Model document or a new version of the Protocol document. Changes to the major version number indicate structural or syntactic changes that make it impossible for older version IPP processors to correctly parse and interpret the new or changed attributes, operations and responses. If the major version number changes, the minor version numbers is set to zero. One example that would have required a change to the major version number would have been adding the "ipp-attribute-fidelity" attribute if it had not been part of version 1.0. Items that might affect the changing of the major version deBry, Hastings, Herriot, Isaacson, Powell [Page 23] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 number include any changes to the protocol specification itself such as: - reordering of ordered attributes or attribute sets - changes to the syntax of existing attributes - changing OPTIONAL to MANDATORY and vice versa Changes to the minor version number indicate the addition of new features, attributes and attribute values that may not be understood by all IPP processors, but which can be ignored if not understood. Items that might affect the changing of the minor version number include any changes to the model objects and attributes but not the protocol specification itself, such as: - grouping all extensions not included in a previous version into a new version - formally adding in new attribute values - changing any of the type1 attributes 3.1.7 Job Creation Operations In order to "submit a print job" and create a new Job object, a client issues a create request. A create request is any one of following three operation requests: - The Print-Job Request: A client that wants to submit a print job with only a single document uses the Print-Job operation. . The operation allows for the client to "push" the document data to the Printer by including the document data in the request itself. - The Print-URI Request: A client that wants to submit a print job with only a single document where the Printer "pulls" the document data uses the Print-URI operation. In this case, the client includes only a URI reference to the document data (not the document data itself). - The Create-Job Request: A client that wants to submit a print job with multiple documents uses the Create-Job operation. . This operation is followed by an arbitrary number of Send-Document or Send-URI operations (each creating another document for the newly create Job object). The Send-Document operation includes the document data in the request (the client "pushes" the document data to the printer), and the Send-URI operation includes only a URI reference to the document data in the request (the Printer "pulls" the document data from the referenced location). The last Send-Document or Send-URI request for a given Job object includes a "last-document" operation attribute set to 'true' indicating that this is the last document. deBry, Hastings, Herriot, Isaacson, Powell [Page 24] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Throughout this model specification, the term "create request" is used to refer to any of these three operation requests. A Create-Job operation followed by only one Send-Document operation is semantically equivalent to a Print-Job operation, however, for performance reasons, the client SHOULD use the Print-Job operation for all single Document Jobs. Also, Print-Job is a MANDATORY operation (all implementations MUST support it) whereas Create-Job is an OPTIONAL operation, hence some implementations might not support it. Section 15 describes the rules and issues surrounding the processing and either the acceptance or rejection of a create request. Job submission time is the point in time when a client issues a create request. The initial state of every Job object is the 'pending' or 'pending-held' state. Later, the Printer object begins processing the job. At this point in time, the Job object's state moves to 'processing'. This is known as job processing time. There are validation checks that must be done at job submission time and others that must be performed at job processing time. At job submission time and at the time a Validate-Job operation is received, the Printer MUST do the following: 1. Process the client supplied attributes using the rules supplied in section 15 and either accept or reject the request 2. Validate the syntax of and support for the scheme of any client supplied URI At job submission time the Printer SHOULD NOT perform the validation checks reserved for job processing time such as: 1. Validate the document data 2. Validate the actual contents of any client supplied URI (resolve the reference and follow the link to the document data) At job submission time, these additional job processing time validation checks are essentially useless, since they require actually parsing and interpreting the document data, are not guaranteed to be 100% accurate, and must yet be done again at job processing time. Also, in the case of a URI, checking for availability at job submission time does not guarantee availability at job processing time. In addition, at job processing time, the Printer object might discover any of the following conditions that were not detectable at job submission time: - runtime errors in the document data, deBry, Hastings, Herriot, Isaacson, Powell [Page 25] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 - nested document data that is in an unsupported format, - the URI reference is no longer valid (i.e., the server hosting the document might be down), or - any other job processing error At job processing time, since the Printer has already responded with a successful status code in the response to the create request, if the Printer object detects an error, the Printer object in unable to inform the end user of the error with an operational status code. In this case, the Printer, depending on the error, can set the "job- state", "job-state-reasons", or "job-state-message" attributes to the appropriate value(s) so that later queries can report the correct job status. 3.2 Printer Operations All Printer operations are directed at Printer objects. A client MUST always supply the "printer-uri" attribute in order to identify the correct target of the operation. In HTTP/1.1 mapping of IPP, this attribute is not supplied in the body of the operation as other operation attributes are. It is supplied in the "request-URI" field in the HTTP header. 3.2.1 Print-Job Operation When an end user desires to submit a print job with only one document and the client supplies the document data (rather than just a reference to the data), the client uses a Print-Job operation. 3.2.1.1 Print-Job Request The following groups of attributes are supplied as part of the Print- Job Request: Group1: Operation Attributes Target: The "printer-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "job-name" (name): This attribute is OPTIONALLY supplied by the client, and it contains the client supplied Job name. If this attribute is deBry, Hastings, Herriot, Isaacson, Powell [Page 26] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 supplied, its value it used for the "job-name" attribute of the newly created Job object. If this attribute is not supplied by the client, the Printer generates a name to use in the "job-name" attribute of the newly created Job object (see Section 4.3.4). "document-name" (name): This attribute is OPTIONALLY supplied by the client, and it contains the client supplied document name. The document name MAY be different than the Job name. Typically, the client software automatically supplies the document name on behalf of the end user by using a file name or an application generated name. If this attribute is supplied, its value can be used in a manner defined by each implementation. Examples include: printed along with the Job (banner page, page adornments, etc.), used by accounting or resource tracking management tools, or even stored along with the document as a document level attribute. IPP/1.0 does not support the concept of document level attributes, however, a vendor specific extension to IPP/1.0 might support the document level attributes. In this case, the "document-name" attribute could be persistently stored along with the document and queried using a Get-Attributes operation on the Job object that includes a request for document level attributes or some other private extension mechanism. "ipp-attribute-fidelity" (boolean): This attribute is OPTIONALLY supplied by the client. If not supplied, the Printer object assumes the value is 'false'. The value 'true' indicates that total fidelity to client supplied attributes and values is required. The value 'false' indicates that a reasonable attempt to print the Job is acceptable. All Printer objects MUST support both types of job processing. See section 15 for a full description of "ipp-attribute-fidelity" and its relationship to other attributes, especially the Printer object's "pdl-override" attribute. "document-charset" (charSet): This attribute is OPTIONALLY supplied by the client. A Printer object SHALL support this attribute if it supports a document- format that requires a character set to be identified in order to unambiguously interpret the document, such as 'text/plain'. There are no particular values required for the Printer object to support. This attribute specifies the charset of the document for those document-formats that require a specification of the charset in order to image the document unambiguously. If the value of the "document-format" attribute contains a charset parameter (see 'mimeType' attribute syntax in Section 4.1.9), the client SHALL also supply the "document-charset" attribute and its value SHALL be the same. deBry, Hastings, Herriot, Isaacson, Powell [Page 27] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 "document-natural-language" (naturalLanguage): This attribute is OPTIONALLY supplied by the client. There are no particular values are required for the Printer object to support. This attribute specifies the natural language of the document for those document-formats that require a specification of the natural language in order to image the document unambiguously. Group2: Job Template Attributes The client OPTIONALLY supplies a set of Job Template attributes as defined in section 4.2. See section 15 for a full description of Job Template attributes. Group 3: Document Content The client MUST supply the document data to be processed. Note: The simplest Print-Job Request consists of just the Document Content and nothing else. In this case, the Printer object: - creates a new Job object (the Job object contains a single document), - stores a generated Job name in the "job-name" attribute, - assumes that the document data is in a supported format, and - uses its corresponding default value attributes for missing Job Template attributes and embedded instructions in the document data. 3.2.1.2 Print-Job Response The Printer SHALL return to the client the following sets of attributes as part of the Print-Job Response: Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. deBry, Hastings, Herriot, Isaacson, Powell [Page 28] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Group 2: Job Object Attributes "job-uri" (uri): The Printer object MUST return the Job object's MANDATORY "job- uri" attribute. "job-id": The Printer object MUST return the Job object's MANDATORY "job- id" attribute. "job-state": The Printer object MUST return the Job object's MANDATORY "job- state" attribute. The value of this attribute (along with the value of the next attribute "job-state-reasons") is taken from a "snapshot" of the new Job object at some meaningful point in time (implementation defined) between when the Printer object receives the Print-Job Request and when the Printer object returns the response. "job-state-reasons": The Printer object OPTIONALLY returns the Job object's OPTIONAL "job-state-reasons" attribute. If the Printer object supports this attribute then it MUST be returned in the response. If this attribute is not returned in the response, the client can assume that the "job-state-reasons" attribute is not supported and will not be returned in a subsequent Job object query. "job-state-message": The Printer object OPTIONALLY returns the Job object's OPTIONAL "job-state-message" attribute. If the Printer object supports this attribute then it MUST be returned in the response. If this attribute is not returned in the response, the client can assume that the "job-state-message" attribute is not supported and will not be returned in a subsequent Job object query. "number-of-intervening-jobs": The Printer object OPTIONALLY returns the Job object's OPTIONAL "number-of-intervening-jobs" attribute. If the Printer object supports this attribute then it MUST be returned in the response. If this attribute is not returned in the response, the client can assume that the "number-of-intervening-jobs" attribute is not supported and will not be returned in a subsequent Job object query. Note: Since any printer state information which affects a job's state is reflected in the "job-state" and "job-state-reasons" attributes, it is sufficient to return only these attributes and no specific printer status attributes. deBry, Hastings, Herriot, Isaacson, Powell [Page 29] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Group 3: Unsupported Attributes This is an OPTIONAL set of attributes. It is a set of Job Template attributes supplied by the client (in the request) that are not supported by the Printer object. When the Printer object rejects the request because of more than one unsupported attribute (see section 15), it SHOULD return all of the unsupported attributes. Some implementations may choose to only return the first unsupported attribute that is encountered during the processing of the attributes, but that may lead to additional requests with only one "fixed" attribute from the set of problem attributes. In the case where the Printer object accepts the request and creates a Job object, the Printer MUST return the set of unsupported attributes where substitutions were made or the attribute was completely ignored. Unsupported attributes fall into two categories: 1. The Printer object does not support the named attribute (no matter what the value), or 2. The Printer object does supports the attribute, but not the particular value supplied by the client (i.e., the Printer does not have that value in the corresponding supported values attribute). In the case of an unsupported attribute name, the Printer object returns the client supplied attribute with a substituted special value of 'unsupported' indicating no support for the attribute itself. In the case of a supported attribute with an unsupported value, the Printer object simply returns the client-supplied attribute. This indicates support for the attribute, but no support for that particular value. Note: The simplest response consists of the just the MANDATORY Job Attributes and a status code of "successful-ok". 3.2.2 Print-URI Operation This operation is identical to the Print-Job operation (section 3.2.1) except that a client supplies a URI reference to the document data using the "document-uri" (uri) operation attribute rather than including the document data itself. It is up to the IPP server to interpret the URI and subsequently "pull" the document from the source referenced by the URI string. At job submission time, the Printer MUST validate the fact that it supports the retrieval method (e.g., http, ftp, etc.) implied by the URI. If the Printer object supports deBry, Hastings, Herriot, Isaacson, Powell [Page 30] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 this operation, it MUST support the "reference-uri-schemes-supported" attribute (see section 4.4.21). 3.2.3 Validate-Job Operation This operation is similar to the Print-Job operation (section 3.2.1) except that a client supplies no document data and the Printer allocates no resources (i.e., it does not create a new Job object). This operation is used only to verify capabilities of a printer object against whatever attributes are supplied by the client in the Validate-Job request. There are no Job Object Attributes returned in the Validate-Job Response. If the Printer supports either the Print- URI or Send-URI operations, the client MAY include a "document-uri" attribute in the request. In this case, the Printer MUST validate that the Printer supports the retrieval method implied by the URI, and SHOULD check for validate URI syntax. The Printer NEED NOT follow the reference and validate the contents of the reference. If all is well, the Printer returns the status code "successful-ok". Otherwise, the Printer returns a set of unsupported attributes and/or the appropriate error status code. If the client supplies the "ipp-attribute- fidelity" attribute set to false (or does not supply the attribute at all) and if the Printer object returns a "successful-ok-ignored-or- substituted-attributes", the Printer object SHOULD return all ignored or substituted in the Unsupported Attributes group. In such a case, the Printer object MUST return at least one attribute indicating an unsupported attribute value or an ignored attribute. 3.2.4 Create-Job Operation This operation is similar to the Print-Job operation (section 3.2.1) except that in the Create-Job request , a client does not supply document data (or any reference to document data). Also, the client does not supply any of the "document-name", "content-charset", or "content-natural-language" attributes. This operation is followed by one or more Send-Document or Send-URI operations. In each of these operation requests, the client OPTIONALLY supplies the "document- name", "content-charset", or "content-natural-language" attributes for each document in the multi-document Job. If a Printer object supports the Create-Job operation, it MUST also support the Send-Document operation and also MAY support the Send-URI operation. 3.2.5 Get-Attributes Operation The Printer Get-Attributes operation allows a client to obtain information from a Printer object. In the operations attributes in a request, the client supplies the set of attribute names and/or attribute group names in which the requester is interested. In the operation attribute in the response, the Printer returns a deBry, Hastings, Herriot, Isaacson, Powell [Page 31] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 corresponding attribute set with the appropriate attribute values filled in. For Printers, the possible names of attribute groups are: - 'job-template': all of the Job Template attributes that apply to a Printer object (the last two columns of the table in Section 4.2). - 'printer-description': the attributes specified in Section 4.4. There is also the special group 'all' that includes all supported attributes. Since a client MAY request specific attributes or named groups, there is a potential that there is some overlap. For example, if a client requests, 'printer-name', 'printer-description', and 'all', client is actually requesting the "printer-group, and once by inclusion in the 'all' group. In all cases, the Printer SHALL only return the attribute once in the response. It is NOT REQUIRED that a Printer support all attributes belonging to a group, however it is MANDATORY that each Printer implementation understand all group names. 3.2.5.1 Get-Attributes Request The following sets of attributes are part of the Get-Attributes Request when the request is directed to a Printer object: Group 1: Operation Attributes Target: The "printer-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "requested-attributes" (1setOf keyword) : The client OPTIONALLY supplies a set of attribute names and/or attribute group names in whose values the requester is interested. If the client omits this attribute, the Printer SHALL respond as if this attribute had been supplied with a value of 'all'. "document-format" (mimeType) : The client OPTIONALLY supplies this attribute. This attribute is useful for a Printer to determine the set of supported attribute values that relate to the requested document format. The Printer deBry, Hastings, Herriot, Isaacson, Powell [Page 32] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 SHOULD return only (1) those attributes that are supported for that format and (2) the attribute values that are supported for the specified document format. By specifying the document format, the client can get the Printer to eliminate the attributes and values that are not supported for a specific document format. For example, a Printer might have multiple interpreters to support both 'application/postscript' (for PostScript) and 'text/plain' (for text) documents. However, for only one of those interpreters might the Printer be able to support "number-up" with values of '1', '2', and '4'. For the other interpreter it might be able to only support "number-up" with a value of '1'. If the client omits this attribute, the Printer SHALL respond as if the attribute had been supplied with a value set to the Printer object's "document-format-default" default value attribute. It is recommended that the client always supply a value for "document-format", since the Printer object's "document-format-default" may be 'application/octet-stream', in which case the returned attributes and values are for the union of the document formats that the Printer can automatically sense. For more details, see the description of the 'mimeType' attribute syntax in section 4.1.9. NOTE: The "document-format" operation attribute is a fairly sophisticated filtering notion that is not supported by many existing print systems or devices. 3.2.5.2 Get-Attributes Response The Printer object returns the following sets of attributes as part of the Get-Attributes Response: Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. Group 2: Requested Printer Object Attributes deBry, Hastings, Herriot, Isaacson, Powell [Page 33] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 This is the set of requested attributes and their current values. The Printer object ignores (does not respond with) any requested attribute which is not supported. 3.2.6 Get-Jobs Operation The Get-Jobs operation allows a client to retrieve the list of Jobs belonging to the target Printer object. The client may also supply a list of Job attribute names or attribute group names. These Job attributes will be returned for each Job that is returned. This operation is similar Get-Attributes, except that this Get-Jobs operation returns attributes from possibly more than one object (see the description of attribute group names in section 3.3.4). 3.2.6.1 Get-Jobs Request The client submits the Get-Jobs request to a Printer object. The following groupsof attributes are part of the Get-Jobs Request: Group 1: Operation Attributes Target: The "printer-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "limit" (integer): The client OPTIONALLY supplies this attribute. It is an integer value that indicates a limit to the number of Job objects returned. The limit is a "stateless limit" in that if the value supplied by the client is 'n', then only the first 'n' jobs are returned in the Get-Jobs Response. There is no mechanism to allow for the next 'm' jobs after the first 'n' jobs. If the client does not supply this attribute, the Printer object responds will all applicable jobs. "requested-attributes" (1setOf keyword): The client OPTIONALLY supplies this attribute. It is a set of Job attribute names or attribute groups names in whose values the requester is interested. This set of attributes is returned for each Job that is returned. The allowed attribute group names are the same as those defined in the Get-Attributes operation for Job objects. If the client does not supply this attribute, the deBry, Hastings, Herriot, Isaacson, Powell [Page 34] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Printer SHALL respond as if the client had supplied values of 'job-uri' and 'job-id'. "which-jobs" (keyword): The client OPTIONALLY supplies this attribute. It indicates which Jobs should be returned by the Printer object. The values for this attribute are: 'completed': This includes any Job object whose state is 'completed', 'cancelled', or 'aborted'. 'not-completed': This includes any Job object whose state is 'pending', 'processing', 'processing-stopped', 'pending- held', 'unknown'. If the client does not supply the attribute, the Printer object SHALL respond as if the client had supplied the value of 'not- completed'. 3.2.6.2 Get-Jobs Response The Printer object returns all of the Job objects that match the criteria as defined by the attribute values supplied by the client in the request. It is possible that no Job objects are returned since there may literally be no Job objects at the Printer, or there may be no Job objects that match the criteria supplied by the client. If the client requests any Job attributes at all, there is a set of Job Object Attributes returned for each Job object. Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. Groups 2 to N: Job Object Attributes The Printer object responds with one set of Job Object Attributes for each returned Job object. For any job submitted in a different natural language than the natural language that the client is requesting in the Get-Jobs request, the Printer SHALL indicate the submitted natural language by returning the "job-natural-language" as the first Job deBry, Hastings, Herriot, Isaacson, Powell [Page 35] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 object attribute, which overrides the "attributes-natural- language" operation attribute value being returned by the Printer. If any returned 'text' or 'name' attribute includes an exception natural language as described in the 'text' attribute syntax (see Section 4.1.1), the exception natural language overrides the "job-natural-language" value (for the immediately following attribute value only). Jobs are returned in the following order: - If the client requests all 'completed' Jobs (Jobs in the 'completed', 'aborted', or 'cancelled' states), then the Jobs are returned newest to oldest (with respect to actual completion time) - If the client requests all 'non-completed' Jobs (Jobs in the 'pending', 'processing', 'pending-held', 'processing-stopped', and 'unknown' states), then Jobs are returned in relative chronological order of expected time to complete (based on whatever scheduling algorithm is configured for the Printer object). 3.3 Job Operations All Job operations are directed at Job objects. A client MUST always supply some means of identifying the Job object in order to identify the correct target of the operation. Since Job objects can be identified with either a single Job URI or a combination of a Printer URI with a local Job ID, the following rules apply to all Job operation requests mapped onto HTTP/1.1: - If the client chooses to identify Job objects with just the Job URI, this "job-uri" attribute is not supplied in the body of the operation as other operation attributes are. It is supplied in the "request-URI" field in the HTTP header. - If the client chooses to identify Job objects with both a Printer URI and a local Job ID, the "printer-uri" attribute is not supplied in the body of the operation, but it is supplied in the "request-URI" field in the HTTP header. The "job-id" attribute is included as an operation attribute. Since the Get-Attributes operation can be both a Printer operation and a Job operation, if a Printer object receives a Get-Attributes request, the Printer object must check for the existence of the "job- id" operation attribute. If present, the operation is intended to be a Job operation on the corresponding Job object. If absent, the operation is intended to be a Printer operation. deBry, Hastings, Herriot, Isaacson, Powell [Page 36] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 3.3.1 Send-Document Operation A client uses a Create-Job operation to create a multi-document Job object that is initially "empty" (contains no documents). In the Create-Job response, the Printer object returns the Job object's URI (the "job-uri" attribute) and the Job object's 32-bit identifier (the "job-id" attribute). For each new document that the client desires to add, the client uses a Send-Document operation. Each Send-Document Request contains the entire stream of document data for one document. Since the Create-Job and the Send-Documents that follow can occur over arbitrarily long periods of time, each Printer object must decide how long to "wait" for the next Send-Document operation. The Printer object OPTIONALLY supports the "multiple-operation-timeout" attribute. This attribute indicates the maximum number of seconds the Printer object will wait for the next Send-Document operation. If the Printer object times-out waiting for the next Send-Document operation, the Printer object MAY decide on any of the following semantic actions: 1. Assume that the Job is an invalid job, start the process of changing the job state to 'aborted', and clean up all resources associated with the Job. In this case, if another Send-Document operation is finally received, the Printer responds with an "client-error-not-possible" or "client-error-not-found" depending on whether or not the Job object is still around when it finally arrives. 2. Assume that the last Send-Document received was in fact the last document (as if the "last-document" flag had been set to 'true'), close the Job, and proceed to process it (i.e., move the Job's state to 'pending'). 3. Assume that the last Send-Document received was in fact the last document, close the Job, but move it to the 'pending-held' to allow an operator to determine whether or not to continue processing the Job by moving it back to the 'pending' state. Each implementation is free to decide the "best" action to take depending on local policy, the value of "ipp-attribute-fidelity", and/or any other piece of information available to it. If the choice is to abort the Job, it is possible that the Job may already have been processed to the point that some pages have been printed. 3.3.1.1 Send-Document Request The following attribute sets are part of the Send-Document Request: Group 1: Operation Attributes deBry, Hastings, Herriot, Isaacson, Powell [Page 37] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Target: Either the "printer-uri" plus "job-id" or "job-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "document-name" (name): The client OPTIONALLY supplies this attribute, and it contains the client supplied document name. The document name MAY be different than the Job name. It might be helpful, but NEED NOT be unique across multiple documents in the same Job. Typically, the client software automatically supplies the document name on behalf of the end user by using a file name or an application generated name. See the description of the "document-name" operation attribute in the Print-Job Request (section 3.2.1.1) for more information about this attribute. "last-document" (boolean): The client MUST supply this attribute. It is a boolean flag that is set to 'true' if this is the last document for the Job, 'false' otherwise. "document-charset" (charSet): This attribute is OPTIONALLY supplied by the client. A Printer object SHALL support this attribute if it supports a document- format that requires a character set to be identified in order to unambiguously interpret the document, such as 'text/plain'. There are no particular values required for the Printer object to support. This attribute specifies the charset of the document for those document-formats that require a specification of the charset in order to image the document unambiguously. If the value of the "document-format" attribute contains a charset parameter (see 'mimeType' attribute syntax in Section 4.1.9), the client SHALL also supply the "document-charset" attribute and its value SHALL be the same. "document-natural-language" (naturalLanguage): This attribute is OPTIONALLY supplied by the client. There are no particular values required for the Printer object to support. This attribute specifies the natural language of the document for those document-formats that require a specification of the natural language in order to image the document unambiguously, such as proper glyph selection.. Group 2: Document Content deBry, Hastings, Herriot, Isaacson, Powell [Page 38] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 The client MUST supply the document data if the "last-document" flag is set to 'false'. However, since a client might not know that the previous document sent with a Send-Document operation was the last document (i.e., the "last-document" attribute was set to 'false'), it is legal to send a Send-Document request with no document data where the "last-document" flag is set to 'true'. 3.3.1.2 Send-Document Response The following sets of attributes are part of the Send-Document Response: Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. Group 2: Job Object Attributes This is the same set of attributes as described in the Print-Job response (see section 3.2.1.2). 3.3.2 Send-URI Operation This operation is identical to the Send-Document operation (see section 3.3.1) except that a client supplies a URI reference ("document-uri" operation attribute) rather than the document data itself. If a Printer object supports this operation, clients can use both Send-URI or Send-Document operations to add new documents to an existing multi-document Job object. The Printer object MUST validate the syntax of the supplied URI before returning a response. If the Printer object supports this operation, it MUST support the URI types defined under the Print-URI operation (see section 3.2.2) 3.3.3 Cancel Job Operation This operation allows a client to cancel a Print Job any time after a create job operation.. Since a Job might already be printing by the deBry, Hastings, Herriot, Isaacson, Powell [Page 39] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 time a Cancel-Job is received, some pages may be printed before the job is actually terminated. 3.3.3.1 Cancel-Job Request The following groups of attributes are part of the Cancel-Job Request: Group 1: Operation Attributes Target: Either the "printer-uri" plus "job-id" or "job-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "message" (text): OPTIONAL message to the operator. This is not the same as the "job-message-from-operator" attribute. This attribute is used to send a message along with the operation request. It is an implementation decision of how or where to display this message (if at all). 3.3.3.2 Cancel-Job Response The following sets of attributes are part of the Cancel-Job Response: Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. Once a successful response has been sent, the implementation guarantees that the Job will eventually end up in the 'cancelled' state. If the implementation is forced to leave the job in the some other state, the "job-state-reasons" SHOULD contain the ' processing- to-stop-point ' value which indicates to later queries that although the Job may still be 'processing', it will eventually end up in the 'cancelled' state, not the 'completed' state. deBry, Hastings, Herriot, Isaacson, Powell [Page 40] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 3.3.4 Get-Attributes Operation The Job Get-Attributes operation allows a client to obtain information from a Job object and it is almost identical to the Get-Attributes operation for a Printer object (see section 3.2.5). The only differences are that the operation is directed at a Job rather than a Printer and there is no "document-format" operation attribute used when querying a Job object. For Jobs, the attribute groups include: - 'job-template': all of the Job Template attributes that apply to a Job object (the first column of the table in Section 4.2). - 'job-description': the attributes specified in Section 4.3. There is also the special group 'all' that includes all supported attributes. If for some reason, the client includes an attribute two or more times in the request (e.g., the client supplies values of 'all', 'job-template', and 'sides' in the "requested-attributes" attribute), the Printer SHALL only return one occurrence of the attribute in the response. 3.3.4.1 Get-Attributes Request The following groups of attributes are part of the Get-Attributes Request when the request is directed at a Job object: Group 1: Operation Attributes Target: Either the "printer-uri" plus "job-id" or "job-uri" target for this operation as described in section 3.1.2. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.1. "requested-attributes" (1setOf keyword) : An OPTIONAL set of attribute names and/or attribute group names in whose values the requester is interested. If the client omits this attribute, the Printer SHALL respond as if this attribute had been supplied with a value of 'all'. 3.3.4.2 Get-Attributes Response The Printer object returns the following sets of attributes as part of the Get-Attributes Response: deBry, Hastings, Herriot, Isaacson, Powell [Page 41] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Group 1: Operation Attributes Status Code and Message: The response includes the MANDATORY status code and an OPTIONAL "status-message" (text) operation attribute as described in section 3.1.4. Natural Language and Character Set: The "attributes-charset" and "attributes-natural-language" attributes as described in section 3.1.3.2. Group 2: Requested Job Object Attributes This is the set of requested attributes and their current values. The Printer object ignores (does not respond with) any requested attribute which is not supported. 4. Object Attributes This section describes the attributes with their corresponding syntaxes and values that are part of the IPP model. The sections below show the objects and their associated attributes which are included within the scope of this protocol. Many of these attributes are derived from other relevant specifications: - Document Printing Application (DPA) [ISODPA] - RFC 1759 Printer MIB [RFC1759] Each attribute is uniquely identified in this document using a "keyword" (see section 12.2.1). The keyword is included in the section header describing that attribute. All attributes are uniquely identified with a keyword as its name. In addition, some attributes are defined having a syntax that is a set of keywords. 4.1 Attribute Syntaxes This section defines the basic attribute syntax types that a client and server SHALL be able to handle. Each attribute description in sections 3 and 4 includes the name of attribute syntax(es) in the heading (in parentheses). A conforming implementation of an attribute SHALL include the semantics of the attribute syntax(es) so identified. Section 6 describes how the protocol can be extended with new attribute syntaxes. Most attributes are defined to have a single attribute syntax. However, a few attributes (e.g., "job-sheet", "media", "job-hold- until") are defined to have several attribute syntaxes, depending on deBry, Hastings, Herriot, Isaacson, Powell [Page 42] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 the value. Since each value SHALL be tagged as to its attribute syntax in the protocol, a single-valued attribute instance may have any one of its attribute syntaxes and a multi-valued attribute instance may have a mixture of its defined attribute syntaxes. The attribute syntaxes are specified in the following sub-sections, where the sub-section heading is the name of the attribute syntax inside the single quotes: 4.1.1 'text' The 'text' attribute syntax is a sequence of one or more characters with a limit of 1 to 4095 octets. The Printer object SHALL support UTF-8 [RFC2044] and MAY support additional charsets provided that they are registered with IANA [IANA-CS]. See Section 4.1.7 for the specification of the 'charSet' attribute syntax, including restricted semantics and examples of charsets. If the client needs to pass or the Printer object needs to return a 'text' attribute in a different natural language than the rest of the 'text' attributes in the request or response as indicated by the "attributes-natural-language" operation attribute (see Section 3.1.3), the client or Printer object SHALL immediately precede that attribute value with a 'naturalLanguage' attribute value that indicates the differing natural language. Thus the attribute becomes multi-valued with two values. This additional values is called an "exception" natural language value. In a create operation, the Printer object SHOULD accept and store an exception natural language value. If the Printer object does not store an exception natural language value, the Printer SHALL ignore it and SHALL store the immediately following 'text' value only. The Printer SHALL not reject the request no matter what value the client supplies as an exception natural language. If the attribute is multi-valued (1setOf text), then the exception natural language value applies only to the next 'text' value. Subsequent values in a multi-valued 'text' attribute in a request or a response revert to the natural language of the operation attribute or the "job-natural-language" job attribute, if present, in the case of a Get-Jobs response. Example: If the client supplies the "attributes-natural-language" operation attribute with the value: 'en' indicating English, but the values of the "job-name" attribute is in French, the values of the normally single-valued "job-name" attribute supplied by the client in any request or returned by the Printer object in any response would be the following two values, each tagged with the appropriate attribute syntax ('naturalLanguage' and 'text') in the protocol: deBry, Hastings, Herriot, Isaacson, Powell [Page 43] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'fr': exception natural language indicating French with attribute syntax 'naturalLanguage' 'Rapport Mensuel': the job name in French with attribute syntax 'name'. 4.1.2 'name' The 'name' attribute syntax is the same as 'text', including the MANDATORY support of UTF-8 and the exception natural language mechanism, except that the sequence of characters is limited so that its encoded form is of length 1 to 255 octets. This syntax type is used for user-friendly strings, such as a Printer name, that, for humans, are more meaningful than identifiers. Note: Only the 'text' and 'name attribute syntaxes permit the exception natural language mechanism. Example: If the client supplies the "attributes-natural-language" operation attribute with the value: 'en' indicating English, but the "printer-name" attribute is in German, the values of the normally single-valued "printer-name" attribute returned by the Printer in any operation response would be the following two values, each tagged with the appropriate attribute syntax ('naturalLanguage' and 'name') in the protocol: 'de': exception natural language indicating German with the attribute syntax 'naturalLanguage' 'Farbdrucker': the Printer name in German with attribute syntax 'name' 4.1.3 'keyword' The 'keyword' attribute syntax is a sequence of characters, length: 1 to 255, containing only the US-ASCII [ASCII] encoded values for lowercase letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"), dot ("."), and underscore ("_"). The first character MUST be a lowercase letter. Furthermore, keywords SHALL be in U.S. English. This syntax type is used for enumerating semantic identifiers of entities in the abstract protocol, i.e., entities identified in this document. Keywords are used as attribute names or values of attributes. Unlike 'text' and 'name' attribute values, 'keyword' values SHALL NOT use the exception natural language mechanism, since they SHALL always be US-ASCII and U.S. English. When accepting keywords from users and displaying keywords to users, clients SHOULD localize the keywords to the charset and natural language of the user. deBry, Hastings, Herriot, Isaacson, Powell [Page 44] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 In the definition for each attribute of this syntax type, the full set of defined keyword values for that attribute are listed. When a keyword is used to represent an attribute (its name), it MUST be unique within the full scope of all IPP objects and attributes. When a keyword is used to represent a value of an attribute, it MUST be unique just within the scope of that attribute. That is, the same keyword SHALL not be used for two different values within the same attribute to mean two different semantic ideas. However, the same keyword MAY be used across two or more attributes, representing different semantic ideas for each attribute. Section 6 describes how the protocol can be extended with new keyword values. Examples of attribute name keywords: "job-name" "attributes-charset " 4.1.4 'enum' The 'enum' attribute syntax is an enumerated integer value that is in the range from -2**31 to 2**31 - 1. Each value has an associated 'keyword' name. In the definition for each attribute of this syntax type, the full set of possible values for that attribute are listed.. This syntax type is used for attributes for which there are enum values assigned by other standards, such as SNMP MIBs. A number of attribute enum values in this specification are also used for corresponding attributes in other standards [RFC1759].. This syntax type is not used for attributes to which the system administrator may assign values. Section 6 describes how the protocol can be extended with new enum values. Though this document includes a symbolic name for each enum value (in U.S. English), when accepting enum names from users and displaying enum names to users, clients SHOULD localize the names to the charset and natural language of the user. 4.1.5 'uri' The 'uri' attribute syntax is any valid Uniform Resource Identifier or URI [RFC1630]. Most often, URIs are simply Uniform Resource Locators or URLs [RFC1738] [RFC1808]. 4.1.6 'uriScheme' The 'uriScheme' attribute syntax is a sequence of characters representing a URI scheme according to RFC 1738 [RFC1738]. Standard values for this syntax type are the following keywords: 'http': for HTTP schemed URIs (e.g., "http://...") 'ftp': for FTP schemed URIs (e.g., "ftp://...") deBry, Hastings, Herriot, Isaacson, Powell [Page 45] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'mailto': for SMTP schemed URIs (e.g., "mailto:...") 'file': for file schemed URIs (e.g., "file:...") 4.1.7 'charSet' The 'charSet' attribute syntax is a standard identifier of a coded character set and encoding scheme for labeling certain document contents and 'text' and 'name' attribute values. The syntax and semantics of this attribute syntax are specified in RFC 2046 [RFC2046] and contained in the IANA character-set Registry [IANA-CS] according to the IANA procedures [IANA-CSa]. As specified in RFC 2046, the values SHALL be case-insensitive and SHALL be in US-ASCII. When a character-set in the IANA registry has more than one name (alias), the name labeled as "(preferred MIME name)" SHALL be used. Some examples are: 'utf-8': ISO 10646 Universal Multiple-Octet Coded Character Set (UCS) represented as the UTF-8 [RFC2044] transfer encoding scheme in which US-ASCII is a subset charset. The 'utf-8' charset value supplied in the "attributes-charset" operation attribute (see Section 3.1.3), which is used to identify the charset of 'text' and 'name' attributes, SHALL be restricted to conformance level 2 of ISO 10646 [ISO10646-1], so that accented letters SHALL NOT be represented with non-spacing accents. This same 'utf-8' value supplied in the "document-format" operation attribute (see Sections 3.2.1.1 and 3.3.1.1), MAY include level 3 of ISO 10646. 'US-ASCII': 7-bit American Standard Code for Information Interchange (ASCII), ANSI X3.4-1986 [ASCII]. This standard defines US-ASCII, but RFC 2045 [46] eliminates most of the control characters from conformant usage in MIME and IPP. 'iso-8859-1': 8-bit One-Byte Coded Character Set, Latin Alphabet Nr 1 [ISO8859-1]. This defines a coded character set that is used by Latin languages in the Western Hemisphere and Western Europe. US-ASCII is a subset charset. Some attribute descriptions MAY place additional requirements on charset values that may be used, such as MANDATORY values the MUST be supported or additional restrictions, such as requiring that the charset have US-ASCII as a subset charset. 4.1.8 'naturalLanguage' The 'naturalLanguage' attribute syntax is a standard identifier for a natural language and optionally a country. The values for this syntax type are taken from RFC 1766 [RFC1766]. As specified in RFC 1766, the values SHALL be case-insensitive and SHALL be in US-ASCII. Examples include: deBry, Hastings, Herriot, Isaacson, Powell [Page 46] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'en': for English 'en-us': for US English 'FR': for French 'de': for German 4.1.9 'mimeType' The 'mimeType' attribute syntax is the standard defined Internet Media Type (sometimes called MIME type) as defined by RFC 2046 [RFC2046] and registered according to the procedures of RFC 2048 [RFC2048] for identifying a document format. The value MAY include a charset parameter, depending on the specification of the Media Type in the IANA Registry [IANA-MT]. Examples: 'text/html': An HTML document 'text/plain': A plain text document in US-ASCII (RFC 2046 indicates that in the absence of the charset parameter SHALL mean US-ASCII rather than simply unspecified) [RFC2046]. 'text/plain; charset=US-ASCII': A plain text document in US-ASCII [52, 56]. 'text/plain; charset=ISO-8859-1': A plain text document in ISO 8859-1 (Latin 1) [ISO8859-1]. 'text/plain; charset=utf-8': A plain text document in ISO 10646 represented as UTF-8 [RFC2044] 'text/plain, charset=iso-10646-ucs-2': A plain text document in ISO 10646 represented in two octets (UCS-2) [ISO10646-1] 'application/postscript': A PostScript document [RFC2046] 'application/vnd.hp-PCL': A PCL document [IANA-MT] (charset escape sequence embedded in the document data) 'application/octet-stream': Auto-sense - see below One special type is 'application/octet-stream'. If the Printer object supports this value, the Printer object or the device SHALL be capable of auto-sensing the format of the document data. If the Printer object's default value attribute is set to 'application/octet- stream' the Printer object not only supports auto-sensing of the document format, but will depend on the result of applying its auto- sensing algorithm in the case of missing information not supplied by the client. If the client supplies a document format value, the Printer SHOULD rely on the supplied attribute, rather than trust its auto-sensing algorithm. To summarize: 1. If the client does not supply a document format value, the Printer MUST rely on its default value setting (which may be 'application/octet-stream' indicating an auto-sensing mechanism). 2. If the client supplies a value other than 'application/octet- stream', the client is supplying valid information about the format of the document data and the Printer object SHOULD trust deBry, Hastings, Herriot, Isaacson, Powell [Page 47] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 the client supplied value more than the outcome of applying an automatic format detection mechanism. For example, the client may be requesting the printing of a PostScript file as a 'text/plain' document. The Printer object SHOULD print a text representation of the PostScript commands rather than interpret the stream of PostScript commands and print the result. 3. If the client supplies a value of 'application/octet-stream', the client is indicating that the Printer object SHOULD use its auto-sensing mechanism whether auto-sensing is the Printer object's default or not. 4.1.10 'octetString' The 'octetString' attribute syntax is a sequence of octets. This syntax type is used for opaque data 4.1.11 'boolean' The 'boolean' attribute syntax is like a keyword with only two values 'true' and 'false'. 4.1.12 'integer' The 'integer' attribute syntax is an integer value that is in the range from -2**31 to 2**31 - 1. Each individual attribute may specify the range constraint explicitly if the range is different from the full range of possible integer values (e.g., 0 - 100 for the "job- priority" attribute), however, the enforcement of that additional constraint is up to the IPP objects, not the protocol. 4.1.13 'rangeOfInteger' The 'rangeOfInteger' attribute syntax is an ordered set of two integers, the smallest first, followed by the largest. The pair of integers identifies an inclusive range of integer values. 4.1.14 'dateTime' The 'dateTime' attribute syntax is a standard, fixed length representation of the "DateAndTime" syntax as defined in RFC 1514 [RFC1514] and RFC 1903 [RFC1903]. When accepting 'dateTime' values from users and displaying 'dateTime' values to users, clients SHOULD localize the values to the charset and natural language of the user. 4.1.15 'resolution' The 'resolution' attribute syntax specifies a two-dimensional resolution in the indicated units. It consists of 3 integers: a cross deBry, Hastings, Herriot, Isaacson, Powell [Page 48] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 feed direction resolution (positive integer value), a feed direction resolution (positive integer value), and a units value. The semantics of these three components are taken from the Printer MIB [RFC1759] suggested values. That is, the cross feed direction component resolution component is the same as the prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed direction component resolution component is the same as the prtMarkerAddressabilityFeedDir in the Printer MIB, and the units component is the same as the prtMarkerAddressabilityUnit object in the Printer MIB (namely dots per inch and dots per centimeter). All three values MUST be present even if the first two values are the same. Example: '300', '600', '3' indicates a 300 dpi cross-feed direction resolution, a 600 dpi feed direction resolution, since a '3' indicates dots per inch. 4.1.16 '1setOf X' The '1setOf X' attribute syntax is 1 or more values of attribute syntax type X. This syntax type is used for multi-valued attributes. The syntax type is called '1setOf' rather than just 'setOf' as a reminder that the set of values SHALL NOT be empty (i.e., a set of size 0). Sets are normally unordered, however each attribute description of this type may specify that the values MUST be in a certain order for that attribute. 4.2 Job Template Attributes Job Template attributes describe job processing behavior. Support for Job Template attributes by a Printer object is OPTIONAL (see section 12.2.3 for a description of support for OPTIONAL attributes). Also, clients OPTIONALLY supply Job Template attributes in create requests. Job Template attributes conform to the following rules. For each Job Template attribute called "foo": 1. The Printer object OPTIOINALLY supports a "foo-supported" attribute that describes which job processing behaviors are supported by that Printer object. A client can query the Printer object to find out what foo-related behaviors are supported by inspecting the returned values of the "foo-supported" attribute. 2. The Printer also OPTIONALLY supports a default value attribute named "foo-default". This default value attribute describes what will be done when no other job processing information is supplied by the client (either explicitly as an IPP attribute in the create request or implicitly as an embedded instruction within the document data). If the Printer supports either the "foo- deBry, Hastings, Herriot, Isaacson, Powell [Page 49] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 default" default value attribute or the "foo-supported" attribute, the Printer MUST support both. 3. "foo" is OPTIOINALLY supplied by the client in a create request. If "foo" is supplied, the client is specifying that the Printer SHALL apply the corresponding job processing behavior to this Job while processing the Job. When "foo" is not supplied, the client is specifying that the Printer apply the default job processing behavior. NOTE: Since an administrator MAY change the default value attribute after a Job has been submitted but before it has been processed, the default value used by the Printer object at job processing time may be different that the default value in effect at job submission time. If an application wishes to present an end user with a list of supported values from which to choose, the application SHOULD query the Printer for the supported values. The application SHOULD also query the default value attributes. If the application then limits selectable values to only those value that are supported, the application can guarantee that the values supplied by the client in the create request all fall within the set of supported values at the Printer. When querying the Printer, the client MAY enumerate each attribute by name in the Get-Attributes Request, or the client MAY just name the "job-template" group in order to get the complete set of supported attributes (both supported and default attributes). The "finishings" attribute is an example of a Job Template attribute. It can take on a set of values such as 'staple', 'punch', and/or 'cover'. A client can query the Printer object for the "finishings- supported" attribute and the "finishings-default" attribute. The supported attribute contains a set of supported values. The default value attribute contains the finishing value(s) that will be used for a new Job if the client does not supply a "finishings" attribute in the create request. If the client does supply the "finishings" attribute in the create request, the Printer validates the value or values to make sure that they are a subset of the supported values. If the client-supplied values are all supported, the Job object is created with a "finishings" attribute that is populated with the values supplied by the client. Subsequently, when the Job object is queried, it returns the values supplied by the client. If the client does not supply a "finishings" attribute in the create request, the Job object is created, but no "finishings" attribute is associated with the new Job object. A subsequent query of the Job object will return no "finishings" attribute. In this case, the querying client knows that there were was no client supplied "finishings" attribute. If the client is interested to know what the default value is that the deBry, Hastings, Herriot, Isaacson, Powell [Page 50] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Printer will use for the missing attribute, the client can query the Printer object's default value "finishings-default" attribute to find out how the Job will be finished. The table below summarizes the names and relationships for all Job Template attributes. The first column of the table (labeled "Job") shows the name and syntax for each Job Template attribute in the Job object. These are the attributes that can optionally be supplied by the client in a create request. The last two columns (labeled "Printer: Default Value" and "Printer: Supported Values") shows the name and syntax for each Job Template attribute in the Printer object (the default value attribute and the supported values attribute). A "No" in the table means the Printer SHALL NOT support the attribute (that is the attribute is simply not applicable). deBry, Hastings, Herriot, Isaacson, Powell [Page 51] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 +===================+======================+======================+ | Job Attribute |Printer: Default Value| Printer: Supported | | | Attribute | Values Attribute | +===================+======================+======================+ | job-sheets | job-sheets-default |job-sheets-supported | | (type4 keyword, | (type4 keyword, |(1setOf type4 keyword,| | name) | name) | name) | | | | | +-------------------+----------------------+----------------------+ | job-priority | job-priority-default |job-priority-supported| | (integer 1:100) | (integer 1:100) |(integer 1:100) | | | | | +-------------------+----------------------+----------------------+ | job-hold-until | job-hold-until- |job-hold-until- | | (type4 keyword, | default | supported | | name) | (type4 keyword, |(1setOf type4 keyword,| | name) | name) | name) | +-------------------+----------------------+----------------------+ |multiple-document- |multiple-document- |multiple-document- | | handling | handling-default |handling-supported | | (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)| +-------------------+----------------------+----------------------+ | media | media-default | media-supported | | (type4 keyword, | (type4 keyword, |(1setOf type4 keyword,| | name) | name) | name) | | | | | | | | media-ready | | | |(1setOf type4 keyword,| | | | name) | | | | | +-------------------+----------------------+----------------------+ | number-up | number-up-default | number-up-supported | | (integer) | (integer) |(1setOf integer) | | | | | +-------------------+----------------------+----------------------+ | sides | sides-default | sides-supported | | (type2 keyword) | (type2 keyword) |(1setOf type2 keyword)| | | | | +-------------------+----------------------+----------------------+ | printer-resolution| printer-resolution- | printer-resolution- | | (resolution) | default | supported | | | (resolution) |(1setOf resolution) | +-------------------+----------------------+----------------------+ | print-quality | print-quality-default| print-quality- | | (type2 enum) | (type2 enum) | supported | | | |(1setOf type2 enum) | +-------------------+----------------------+----------------------+ | finishings | finishings-default | finishings-supported | deBry, Hastings, Herriot, Isaacson, Powell [Page 52] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 |(1setOf type2 enum)|(1setOf type2 enum) |(1setOf type2 enum) | | | | | +-------------------+----------------------+----------------------+ | copies | copies-default | copies-supported | | (integer: 1:MAX) | (integer: 1:MAX) | (integer: 1:MAX) | | | | | | | | collated-copies- | | | | supported | | | | (integer: 1:MAX) | | | | | +-------------------+----------------------+----------------------+ | page-ranges | No | page-ranges- | | (1setOf | | supported (boolean) | | rangeOfInteger) | | | +-------------------+----------------------+----------------------+ | orientation | orientation-default | orientation- | | (type2 enum) | (type2 enum) | supported | | | | (1setOf type2 enum) | +-------------------+----------------------+----------------------+ | document-format | document-format- | document-format- | | (mimeType) | default | supported | | | (mimeType) |(1setOf mimeType) | +-------------------+----------------------+----------------------+ | compression | No | compression-supported| | (type3 keyword) | |(1setOf type3 keyword)| | | | | +-------------------+----------------------+----------------------+ | job-k-octets | No |job-k-octets-supported| | (integer) | | (rangeOf integer) | | | | | +-------------------+----------------------+----------------------+ | job- | No | job-impressions- | | impressions | | supported | | (integer) | | (rangeOf integer) | +-------------------+----------------------+----------------------+ | job-media- | No | job-media-sheets- | | sheets | | supported | | (integer) | | (rangeOf integer) | +-------------------+----------------------+----------------------+ 4.2.1 job-sheets (type4 keyword, name) This attribute determines which if any banner page(s) SHALL be printed with a job. Standard values are: deBry, Hastings, Herriot, Isaacson, Powell [Page 53] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'none': no job sheet is printed 'standard': one or more site specific standard job sheets are printed, e.g. a single start sheet or both start and end sheet is printed An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation. Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4). 4.2.2 job-priority (integer(1:100)) This attribute specifies a priority for scheduling the Job. A higher value specifies a higher priority. The value 1 indicates the lowest possible priority. The value 100 indicates the highest possible priority. Among those jobs that are ready to print, a Printer SHALL print all jobs with a priority value of n before printing those with a priority value of n-1 for all n. The syntax for the "job-priority-supported" is an integer(1:100). This single integer value indicates the number of priority levels supported. For example, if the value of "job-priority-supported" is '3', then the Printer object supports 3 levels of job priorities (let's call them 'high', 'medium', and 'low'). In this case, a client MUST assume the following: A client supplied value in the range 1-33 is the same as any other value in the range 1-33 and any one of those values corresponds to the 'low' priority. A client supplied value in the range 34-66 is the same as any other value in the range 34-66 and any one of those values corresponds to the 'medium' priority. A client supplied value in the range 67-100 is the same as any other value in the range 67-100 and any one of those values corresponds to the 'high' priority. For another example, if the value of "job-priority-supported" is '10', then the Printer object supports 3 levels of job priorities, (let's call them 'one', 'two', ..., and 'ten' with 'one' being the lowest priority and 'ten' being the highest). In this case, a client MUST assume the following: A client supplied value in the range 1-10 is the same as any other value in the range 1-10 and any one of those values corresponds to the 'one' priority. deBry, Hastings, Herriot, Isaacson, Powell [Page 54] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 A client supplied value in the range 11-20 is the same as any other value in the range 11-20 and any one of those values corresponds to the 'two' priority. ... A client supplied value in the range 91-100 is the same as any other value in the range 91-100 and any one of those values corresponds to the 'ten' priority. 4.2.3 job-hold-until (type4 keyword, name) This job attribute specifies the named time period during which the Job SHALL become a candidate for printing. Standard values for named time periods are: 'no-hold': immediately, if there are not other reasons to hold the job. 'day-time': during the day. 'evening': evening 'night': night 'weekend': weekend 'second-shift': second-shift 'third-shift': third-shift (after midnight) An administrator SHALL associate allowable print times with a named time period (by means outside IPP 1.0). An administrator is encouraged to pick names that suggest the type of time period. An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation. If the value of this attribute specifies a time period that is in the future, the Printer SHALL add the 'job-hold-until-specified' value to the job's "job-state-reasons" attribute, move the job to the 'pending- held' state, and SHALL NOT schedule the job for printing until the specified time-period arrives. When the specified time period arrives, the Printer SHALL remove the 'job-hold-until-specified' value from the job's "job-state-reason" attribute and, if no other job reasons that keep it in the 'pending-held' state remain, the Printer SHALL consider the job as a candidate for processing by moving the job to the 'pending' state. If this job attribute value is the named value 'no-hold', or specified time period is in effect has already started, the job SHALL be a candidate for processing immediately. deBry, Hastings, Herriot, Isaacson, Powell [Page 55] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.2.4 multiple-document-handling (type2 keyword) This job attribute is relevant only if a job consists of two or more documents. The attribute controls finishing operations and the placement of print-stream pages into imposed pages and onto media sheets. When the value of the "copies" attribute exceeds 1, it also controls the order in which the copies that result from processing the documents are produced. For the purposes of this explanations, if "a" represents an instance of document data, then the result of processing the data in document "a" is a sequence of media sheets represented by "a(*)". Standard values are: 'single-document': If a Job object has multiple documents, say the document data is called a and b, then the result of processing all the document data (a and then b) SHALL be treated as a single sequence of media sheets for finishing operations; that is, finishing would be performed on the concatenation of the seqeunces a(*),b(*). The Printer SHALL NOT force the data in each document instance to be formatted onto a new print-stream page, nor to start a new imposed page or a new media sheet. If more than one copy is made, the ordering of the sets of media sheets resulting from processing the document data SHALL be a(*), b(*), a(*), b(*),...., and the Printer SHALL force each copy to start on a new media sheet. 'separate-documents-uncollated-copies': If a Job object has multiple documents, say the document data is called a and b, then the result of processing the data in each document instance SHALL be treated as a single sequence of media sheets for finishing operations; that is, the sets a(*) and b(*) would each be finished separately. The Printer SHALL force each copy of the result of process the data in a single document to start on a new media sheet. If more than one copy is made, the ordering of the sets of media sheets resulting from processing the document data SHALL be a(*), a(*), b(*), b(*) .... 'separate-documents-collated-copies': If a Job object has multiple documents, say the document data is called a and b, then the result of processing the data in each document instance SHALL be treated as a single sequence of media sheets for finishing operations; that is, the sets a(*) and b(*) would each be finished separately. If more than one copy is made, the ordering of the sets of media sheets resulting from processing the document data SHALL be a(*), b(*), a(*), b(*), ...., and the Printer SHALL force each document copy to start on a new sheet . 'separate-documents-collated-copies' is the same as 'single-document' with respect to ordering of pages, but not media sheet generation, deBry, Hastings, Herriot, Isaacson, Powell [Page 56] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 since the latter will put the first page of the next document on the back side of a sheet if an odd number of pages have been produced so far for the job, while the former case always force the next document or document copy on to a new sheet. 4.2.5 media (type4 keyword, name) This job attribute identifies the medium that the Printer uses for all pages of the Job. The values for "media" include medium-names, medium-sizes, input-trays and electronic forms so that one attribute specifies the media. If a printer allows a client to specify a medium name as the value of this attribute, such a medium name implicitly selects an input-tray that contains the specified medium. If a printer allows a client to specify a medium size as the value of this attribute, such a medium size implicitly selects a medium name that in turn implicitly selects an input-tray that contains the medium with the specified size. If a printer allows a client to specify an input-tray as the value of this attribute, such an input-tray implicitly selects the medium that is in that input-tray at the time the job prints. This case includes manual- feed input-trays. If a printer allows a client to specify an electronic form as the value of this attribute, such an electronic form implicitly selects a medium-name that in turn implicitly selects an input-tray that contains the medium specified by the electronic form. The electronic form also implicitly selects an image that the Printer SHALL merge with the document data as its prints each page. Standard values are (taken from ISO DPA and the Printer MIB) and are listed in section 14. An administrator MAY define additional values using the 'name' or 'keyword' attribute syntax, depending on implementation. There is also an additional attribute named "media-ready" which differs from "media-supported" in that legal values only include the subset of "media-supported" values that are physically loaded and ready for printing with no operator intervention required. The relationship of this attribute and the other attributes that control document processing is described in section 15.4. 4.2.6 number-up (integer) This job attribute specifies the number of source page-images to impose upon a single side of an instance of a selected medium. For example, if the value is deBry, Hastings, Herriot, Isaacson, Powell [Page 57] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 '1': The Printer SHALL place one logical page on a single side of an instance of the selected medium (MAY add some sort of translation, scaling, or rotation). '2': The Printer SHALL place two logical pages on a single side of an instance of the selected medium (MAY add some sort of translation, scaling, or rotation). '4': The Printer SHALL place four logical pages on a single side of an instance of the selected medium (MAY add some sort of translation, scaling, or rotation). This attribute primarily controls the translation, scaling and rotation of page images, but a site may choose to add embellishments, such as borders to each logical page. Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4) and the relationship of this attribute and the other attributes that control document processing is described in section 15.4. ISSUE: Steve Z.: should this section be changed to include "print- stream page" and "layout page"?? rather than "source page" and "logical page"? 4.2.7 sides (type2 keyword) This attribute specifies how source page-images are to be imposed upon the sides of an instance of a selected medium. The standard values are: 'one-sided': imposes each consecutive source page-image upon the same side of consecutive media sheets. 'two-sided-long-edge': imposes each consecutive pair of source page-image upon front and back sides of consecutive media sheets, such that the orientation of each pair of source-pages on the medium would be correct for the reader as if for binding on the long edge. This imposition is sometimes called 'duplex' or 'head-to-head'. 'two-sided-short-edge': imposes each consecutive pair of source page-image upon front and back sides of consecutive media sheets, such that the orientation of each pair of source-pages on the medium would be correct for the reader as if for binding on the short edge. This imposition is sometimes called 'tumble' or 'head-to-toe'. 'two-sided-long-edge', 'two-sided-short-edge', 'tumble', and 'duplex' all work the same for portrait or landscape. However 'head-to-toe' is 'tumble' in portrait but 'duplex' in landscape. 'head-to-head' also deBry, Hastings, Herriot, Isaacson, Powell [Page 58] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 switches between 'duplex' and 'tumble' when using portrait and landscape modes. Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4) and the relationship of this attribute and the other attributes that control document processing is described in section 15.4. 4.2.8 printer-resolution (resolution) This attribute identifies the resolution that Printer uses for a certain Job. 4.2.9 print-quality (type2 enum) This attribute specifies the print quality that the Printer SHALL use for a certain Job. The standard values are: '3' 'draft': lowest quality available on the printer '4' 'normal': normal or intermediate quality on the printer '5' 'high': highest quality available on the printer 4.2.10 finishings (1setOf type2 enum) This attribute identifies the finishing operations that the Printer uses for each copy of each printed document in a particular Job. For Jobs with multiple documents, the "multiple-document-handling" attribute determines what constitutes a _copy_ for purposes of finishing. Standard values are: '3' 'none': Perform no finishing '4' 'staple': Bind the document(s) with one or more staples. The exact number and placement of the staples is site- defined. '5' 'punch': This value indicates that holes are required in the finished document. The exact number and placement of the holes is site-defined The punch specification MAY be satisfied (in a site- and implementation- specific manner) either by drilling/punching, or by substituting pre-drilled media. '6' 'cover': This value is specified when it is desired to select a non-printed (or pre-printed) cover for the document. This does not supplant the specification of a deBry, Hastings, Herriot, Isaacson, Powell [Page 59] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 printed cover (on cover stock medium) by the document itself. '7' 'bind': This value indicates that a binding is to be applied to the document; the type and placement of the binding is site-defined." Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4). If the client supplies a value of 'none' along with any other combination of values, it is the same as if only that other combination of values had been supplied (that is the 'none' value has no effect). 4.2.11 copies (integer(1:2**31 - 1)) This attribute specifies the number of copies to be printed. On many devices the supported number of collated copies will be limited by the number of physical output bins on the device, and may be different from the number of uncollated copies which can be supported. The "copies-supported" attribute is the limit on the number of uncollated copies supported. The "collated-copies-supported" attribute is the limit on the number of collated copies supported. The value in the "copies-default" default value attribute applies to either collated or uncollated as determined by the value in the "multiple-document- handling-default" attribute. Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4) and the relationship of this attribute and the other attributes that control document processing is described in section 15.4. 4.2.12 page-ranges (1setOf rangeOfInteger) This attribute specifies the pages of a document which are to be printed. In most cases, the exact pages to be printed will be generated by a device driver and this attribute would not be required. However, when printing an archived document which has already been formatted, the end user may elect to print just a subset of the pages contained in the document. In this case, if page-range = n.m is specified, the first page to be printed will be page n. All subsequent pages of the document will be printed through and including page m. "page-ranges-supported" is a boolean value indicating whether or not the printer is capable of supporting the printing of page ranges. This capability may differ from one PDL to another. There is no "page- deBry, Hastings, Herriot, Isaacson, Powell [Page 60] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 ranges-default" attribute. If the "page-ranges" attribute is not supplied by the client, all pages of the document will be printed. 4.2.13 orientation (type2 enum) This attribute specifies the orientation of the content on the output pages to be printed. In most cases, the orientation of the content is specified within the document format generated by the device driver at print time. However, some document formats (such as 'text/plain') do not support the notion of page orientation, and it is possible to bind the orientation after the document content has been generated. This attribute provides an end user with the means to specify orientation for such documents. Standard values are: '1' 'portrait': The content will be imaged across the short edge of the medium. '2' 'landscape': The content will be imaged across the long edge of the medium. Landscape is defined to be a rotation of the logical page to be imaged by +90 degrees with respect to the medium (i.e. anti- clockwise) from the portrait orientation. Note: The +90 direction was chosen because simple finishing on the long edge is the same edge whether portrait or landscape '3' 'reverse-landscape': The content will be imaged across the long edge of the medium. Reverse-landscape is defined to be a rotation of the logical page to be imaged by - 90 degrees with respect to the medium (i.e. clockwise) from the portrait orientation. Note: The 'reverse- landscape' value was added because some applications rotate landscape -90 degrees from portrait, rather than +90 degrees. Note: The effect of this attribute on jobs with multiple documents is controlled by the "multiple-document-handling" job attribute (section 4.2.4) and the relationship of this attribute and the other attributes that control document processing is described in section 15.4. 4.2.14 document-format (mimeType) This attribute identifies the document format of the data to be printed. The standard values for this attribute are Internet Media types which are sometimes called MIME types. See the description of the 'mimeType' attribute syntax in Section 4.1.9. deBry, Hastings, Herriot, Isaacson, Powell [Page 61] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.2.15 compression (type3 keyword) This attribute identifies compression algorithms used on compressed document data. The value of this attribute does not apply the encoding of the IPP operation itself. Standard values are : 'none': no compression is used. 'deflate': ZIP public domain inflate/deflate) compression technology `gzip' GNU zip compression technology described in RFC 1952. 'compress': UNIX compression technology 4.2.16 job-k-octets (integer(0:2**31 - 1)) This attribute specifies the total size of the document data in K octets, i.e., in units of 1024 octets requested to be processed in the job. The value SHALL be rounded up, so that a job between 1 and 1024 octets SHALL be indicated as being 1, 1025 to 2048 SHALL be 2, etc. This value SHALL not include the multiplicative factors contributed by the number of copies specified by the "copies" attribute, independent of whether the device can process multiple copies without making multiple passes over the document data and independent of whether the output is collated or not. Thus the value is independent of the implementation. Note: This attribute and the following two attributes ("job- impressions" and "job-media-sheets") are not intended to be counters; they are intended to be useful routing and scheduling information if known. For these three attributes, the Printer may try to compute the value if it is not supplied in the create request. Even if the client does supply a value for this attribute in the create request, the Printer may choose to change the value if the Printer is able to compute a value which is more accurate than the client supplied value. The Printer may be able to determine the correct value for this attribute either right at job submission time or at any later point in time. If the value of this attribute is unknown, the Printer may choose to respond with a value of '-2' (which signifies "unknown") rather than choose to not support the attribute at all. 4.2.17 job-impressions (integer(0:2**31 - 1)) This attribute specifies the total number of impressions of the document(s) being requested by this job to produce. deBry, Hastings, Herriot, Isaacson, Powell [Page 62] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 This value SHALL not include the multiplicative factors contributed by the number of copies specified by the "copies" attribute, independent of whether the device can process multiple copies without making multiple passes over the document data and independent of whether the output is collated or not. Thus the value is independent of the implementation. 4.2.18 job-media-sheets (integer(0:2**31 - 1)) This attribute specifies the total number of media sheets to be processed for this job. Unlike the "job-k-octets" and the "job-impressions" attributes, this value SHALL include the multiplicative factors contributes by the number of copies specified by the "copies" attribute 4.3 Job Description Attributes The attributes in this section form the attribute group called "job- description". The following table summarizes these attributes. The third column indicates whether the attribute is a MANDATORY attribute that MUST be supported by Printer objects. If it is not MANDATORY, then it is OPTIONAL. deBry, Hastings, Herriot, Isaacson, Powell [Page 63] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 +----------------------------+----------------------+----------------+ | Attribute | Syntax | MANDATORY? | +----------------------------+----------------------+----------------+ | job-uri | uri | MANDATORY | +----------------------------+----------------------+----------------+ | job-id | integer(1:MAX) | MANDATORY | +----------------------------+----------------------+----------------+ | job-more-info | uri | | +----------------------------+----------------------+----------------+ | job-name | name | MANDATORY | +----------------------------+----------------------+----------------+ | job-originating-user | octetString | MANDATORY | +----------------------------+----------------------+----------------+ | job-state | type1 enum | MANDATORY | +----------------------------+----------------------+----------------+ | job-state-reasons | 1setOf type2 keyword | | +----------------------------+----------------------+----------------+ | job-state-message | text | | +----------------------------+----------------------+----------------+ | number-of-documents | integer | | +----------------------------+----------------------+----------------+ | output-device-assigned | name | | +----------------------------+----------------------+----------------+ | time-of-creation | integer | | +----------------------------+----------------------+----------------+ | time-at-processing | integer | | +----------------------------+----------------------+----------------+ | time-at-completed | integer | | +----------------------------+----------------------+----------------+ | number-of-intervening-jobs | integer | | +----------------------------+----------------------+----------------+ | job-message-from-operator | text | | +----------------------------+----------------------+----------------+ | job-k-octets-processed | integer | | +----------------------------+----------------------+----------------+ | job-impressions-completed | integer | | +----------------------------+----------------------+----------------+ | job-media-sheets-completed | integer | | +----------------------------+----------------------+----------------+ | attributes-charset | charSet | MANDATORY | +----------------------------+----------------------+----------------+ | attributes-natural-language| naturalLanguage | MANDATORY | +----------------------------+----------------------+----------------+ 4.3.1 job-uri (uri) deBry, Hastings, Herriot, Isaacson, Powell [Page 64] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 This attribute contains the URI for the job. The Printer, on receipt of a new job, generates a URI which identifies the new Job on that Printer. The Printer returns the value of the "job-uri" attribute as part of the response to a create request. This MUST be an HTTP schemed URI, however the precise format of a Job URI is implementation dependent. For a description of this attribute and its relationship to the following "job-id" attribute, see the discussion in section 2.4 on "Object Identity". 4.3.2 job-id (integer(1:MAX)) This attribute contains the ID of the job. The Printer, on receipt of a new job, generates an ID which identifies the new Job on that Printer. The Printer returns the value of the "job-id" attribute as part of the response to a create request. For a description of this attribute and its relationship to the previous "job-uri" attribute, see the discussion in section 2.4 on "Object Identity". 4.3.3 job-more-info (uri) Similar to "printer-more-info", this attribute contains the URI referencing some resource with more information about this Job object, perhaps an HTML page containing information about the Job. 4.3.4 job-name (name) This attribute is the name of the job. It is a name that is more user friendly than the "job-uri" attribute value. It does not need to be unique between Jobs. The Job's "job-name" attribute is set to the value supplied by the client in the "job-name" operation attribute in the create request. If, however, if the "job-name" operation attribute is not supplied by the client in the create request, the Printer, on creation of the Job, SHALL generate a name. The printer SHOULD generate the value of the Job's "job-name" attribute from the first of the following sources that produces a value: 1) the "document-URI" attribute of the first (or only) document, 2) the "document-name" operation attribute of the first (or only) document, or 3) any other piece of Job specific information. 4.3.5 job-originating-user (octetString) This attribute contains the identity of the end user that submitted the print job. The Printer object sets this attribute to the most deBry, Hastings, Herriot, Isaacson, Powell [Page 65] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 authenticated name that it can obtain from the authentication service over which the IPP operation was received. 4.3.6 job-state (type1 enum) This attribute identifies the current state of the job. Even though the IPP protocol defines eight values for job states, implementations only need to support those states which are appropriate for the particular implementation. In other words, a Printer supports only those job states implemented by the output device and available to the Printer object implementation. Standard values are: 'unknown'(2): The job state is not known, or its state is indeterminate. 'pending'(3): The job is a candidate to start processing, but is not yet processing. 'pending-held'(4): The job is not a candidate for processing for any number of reasons but will return to the 'pending' state as soon as the reasons are no longer present. The job's "job-state- reason" attribute SHALL indicate why the job is no longer a candidate for processing. 'processing'(5): One or more of: 1. the job is using, or is attempting to use, one or more purely software processes that are analyzing, creating, or interpreting a PDL, etc., 2. the job is using, or is attempting to use, one or more hardware devices that are interpreting a PDL, making marks on a medium, and/or performing finishing, such as stapling, etc., 3. the server has made the job ready for printing, but the output device is not yet printing it, either because the job hasn't reached the output device or because the job is queued in the output device or some other spooler, awaiting the output device to print it. Implementations MAY, though they NEED NOT, include additional values in the job's "job-state-reasons" attribute to indicate the progress of the job, such as adding the 'job-printing' value to indicate when the device is actually making marks on a medium. When the job is in the 'processing' state, the entire job state includes the detailed status represented in the printer's "printer-state", "printer-state-reasons", and "printer-state- message" attributes. Implementations MAY include additional values in the job's "job- state-reasons" attribute to indicate the progress of the job, such as adding the 'job-printing' value to indicate when the output device is actually making marks on paper and/or the deBry, Hastings, Herriot, Isaacson, Powell [Page 66] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'processing-to-stop-point' value to indicate that the server or device is in the process of canceling or aborting the job. Most implementations won't bother with this nuance. 'processing-stopped'(6): The job has stopped while processing for any number of reasons and will return to the 'processing' state as soon as the reasons are no longer present. The job's "job-state-reason" attribute MAY indicate why the job has stopped processing. For example, if the output device is stopped, the 'printer-stopped' value MAY be included in the job's "job-state-reasons" attribute. Note: When an output device is stopped, the device usually indicates its condition in human readable form locally at the device. A client can obtain more complete device status remotely by querying the printer's "printer-state", "printer-state- reasons" and "printer-state-message" attributes. 'canceled'(7): The job has been canceled by a Cancel-Job operation and the Printer has completed canceling the job and all job status attributes have reached their final values for the job. While the Printer is canceling the job, the job's "job-state- reasons" attribute SHOULD contain the 'processing-to-stop-point' value and one of the 'canceled-by-user', 'canceled-by-operator', or 'canceled-at-device' value. 'aborted'(8): The job has been aborted by the system, usually while the job was in the 'processing' or 'processing-stopped' state and the Printer has completed aborting the job and all job status attributes have reached their final values for the job. While the server or device is aborting the job, the job's "job- state-reasons" attribute MAY contain the 'processing-to-stop- point' and 'aborted-by-system' values. If supported, the 'aborted-by-system' value SHALL remain while the job is in the 'aborted' state. 'completed'(9): The job has completed successfully or with warnings or errors after processing and all of the job media sheets have been successfully stacked in the appropriate output bin(s). The job's "job-state-reasons" attribute SHOULD contain one of: 'completed-successfully', 'completed-with-warnings', or 'completed-with-errors' values. The final value for this attribute SHALL be one of: 'completed', 'canceled', or 'aborted' before the Printer removes the job altogether. The length of time that jobs remain in the 'canceled', 'aborted', and 'completed' states depends on implementation. The following figure shows the normal job state transitions. deBry, Hastings, Herriot, Isaacson, Powell [Page 67] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 +----> canceled / +----> pending --------> processing ---------+------> completed | ^ ^ \ --->+ | | +----> aborted | v v / +----> pending-held processing-stopped ---+ Normally a job progresses from left to right. Other state transitions are unlikely, but are not forbidden. Not shown are the transitions to the 'canceled' state from the 'pending', 'pending-held', and 'processing-stopped' states. Jobs reach one of the three terminal states: 'completed', 'canceled', or 'aborted', after the jobs have completed all activity, including stacking output media, after the jobs have completed all activity, and all job status attributes have reached their final values for the job. 4.3.7 job-state-reasons (1setOf type2 keyword) This attribute provides additional information about the job's current state, i.e., information that augments the value of the job's "job- state" attribute. Implementation of these values is OPTIONAL, i.e., a Printer NEED NOT implement them, even if (1) the output device supports the functionality represented by the reason and (2) is available to the Printer object implementation. These values MAY be used with any job state or states for which the reason makes sense. Furthermore, when implemented, the Printer SHALL return these values when the reason applies and SHALL NOT return them when the reason no longer applies whether the value of the Job's "job-state" attribute changed or not. When the Job does not have any reasons for being in its current state, the Printer MAY set the value of the Job's "job-state-reasons" attribute to 'none'. NOTE - While values cannot be added to the 'job-state' attribute without impacting deployed clients that take actions upon receiving "job-state" values, it is the intent that additional "job-state- reasons" values can be defined and registered without impacting such deployed clients. In other words, the "job-state-reasons" attribute is intended to be extensible. The following standard values are defined. For ease of understanding, the values are presented in the order in which the reasons are likely to occur (if implemented), starting with the 'job-incoming' value: 'none': There are no reasons for the job's current state. deBry, Hastings, Herriot, Isaacson, Powell [Page 68] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'job-incoming': The CreateJob operation has been accepted by the Printer, but the Printer is expecting additional Send-Document and/or Send-URI operations and/or is accessing/accepting document data. 'submission-interrupted': The job was not completely submitted for some unforeseen reason, such as: (1) the Printer has crashed before the job was closed by the client, (2) the Printer or the document transfer method has crashed in some non-recoverable way before the document data was entirely transferred to the Printer, (3) the client crashed or failed to close the job before the time-out period. 'job-outgoing': The Printer is transmitting the job to the output device. 'job-hold-until-specified': The value of the job's "job-hold- until" attribute was specified with a time period that is still in the future. The job SHALL NOT be a candidate for processing until this reason is removed and there are no other reasons to hold the job. 'resources-are-not-ready': At least one of the resources needed by the job, such as media, fonts, resource objects, etc., is not ready on any of the physical printer's for which the job is a candidate. This condition MAY be detected when the job is accepted, or subsequently while the job is pending or processing, depending on implementation. 'printer-stopped-partly': The value of the Printer's "printer- state-reasons" attribute contains the value 'stopped-partly'. 'printer-stopped': The value of the Printer's "printer-state" attribute is 'stopped'. 'job-interpreting': Job is in the 'processing' state, but more specifically, the Printer is interpreting the document data. 'job-queued': Job is in the 'processing' state, but more specifically, the Printer has queued the document data. 'job-transforming': Job is in the 'processing' state, but more specifically, the Printer is interpreting document data and producing another electronic representation. 'job-printing': The output device is marking media. This value is useful for Printers which spend a great deal of time processing (1) when no marking is happening and then want to show that marking is now happening or (2) when the job is in the process of being canceled or aborted while the job remains in the 'processing' state, but the marking has not yet stopped so that impression or sheet counts are still increasing for the job. 'job-canceled-by-user': The job was canceled by the owner of the job using the Cancel-Job request, i.e., by a user whose name is the same as the value of the job's "job-originating-user" attribute, or by some other authorized end-user, such as a member of the job owner's security group. deBry, Hastings, Herriot, Isaacson, Powell [Page 69] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'job-canceled-by-operator': The job was canceled by the operator using the Cancel-Job request, i.e., by a user who has been authenticated as having operator privileges (whether local or remote). 'job-canceled-at-device': The job was canceled by an unidentified local user, i.e., a user at a console at the device. 'aborted-by-system': The job (1) is in the process of being aborted, (2) has been aborted by the system and placed in the 'aborted' state, or (3) has been aborted by the system and placed in the 'pending-held' state, so that a user or operator can manually try the job again. 'processing-to-stop-point': The requester has issued a Cancel-job operation or the Printer object has aborted the job, but is still performing some actions on the job until a specified stop point occurs or job termination/cleanup is completed. This reason is recommended to be used in conjunction with the 'processing' job state to indicate that the Printer object is still performing some actions on the job while the job remains in the 'processing' state. After all the job's job description attributes have stopped incrementing, the Printer object moves the job from the 'processing' state to the 'canceled' or 'aborted' job states. 'service-off-line': The Printer is off-line and accepting no jobs. All 'pending' jobs are put into the 'pending-held' state. This situation could be true if the service's or document transform's input is impaired or broken. 'job-completed-successfully': The job completed successfully. 'job-completed-with-warnings': The job completed with warnings. 'job-completed-with-errors': The job completed with errors (and possibly warnings too). 4.3.8 job-state-message (text) This attributes specifies supplemental information about the Job State in human readable text. The Printer object SHALL be able to generate this message in any of the natural languages identified by the Printer's "natural-language-supported" attribute (see the "attributes- natural-language" operation attribute specified in Section 3.1.3.1). 4.3.9 number-of-documents (integer(0:2**31 - 1)) This attribute indicates the number of documents in the job, i.e, the number of Send-Document, Send-URI, Print-Job, or Print-URI operations that the Printer has accepted for this job, regardless of whether the document data has reached the Printer or not. deBry, Hastings, Herriot, Isaacson, Powell [Page 70] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Implementations supporting the OPTIONAL Create-Job/Send-Document/Send- URI operations SHOULD support this attribute. 4.3.10 output-device-assigned (name) This attribute identifies the Output Device to which the Printer has assigned this job. If an output device implements an embedded IPP Printer, the Printer NEED NOT set this attribute. If a Print Server implements a Printer, the value MAY be empty until the Printer assigns an output device to the job. 4.3.11 time-of-creation (integer) This attribute indicates the point in time at which the Job object was created. In order to populate this attribute, the Printer object uses the value in its "printer-up-time" attribute at the time the Job object is created. 4.3.12 time-at-processing (integer) This attribute indicates the point in time at which the Job object began processing. In order to populate this attribute, the Printer object uses the value in its "printer-up-time" attribute at the time the Job object is moved into the 'processing' state for the first time. 4.3.13 time-at-completed (integer) This attribute indicates the point in time at which the Job object completed (or was cancelled or aborted). In order to populate this attribute, the Printer object uses the value in its "printer-up-time" attribute at the time the Job object is moved into the 'completed' or 'canceled' or 'aborted' state. 4.3.14 number-of-intervening-jobs (integer(0:2**31 - 1)) This attribute indicates the number of jobs that are "ahead" of this job in the relative chronological order of expected time to complete (i.e., the current scheduled order). For efficiency, it is only necessary to calculate this value when an operation is performed that requests this attribute. 4.3.15 job-message-from-operator (text) This attribute provides a message from an operator, system administrator or "intelligent" process to indicate to the end user the reasons for modification or other management action taken on a job. deBry, Hastings, Herriot, Isaacson, Powell [Page 71] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.3.16 job-k-octets-processed (integer(0:2**31 - 1)) This attribute specifies the number of octets processed in K octets, i.e., in units of 1024 octets. The value SHALL be rounded up, so that a job between 1 and 1024 octets SHALL be indicated as being 1, 1025 to 2048 SHALL be 2, etc. For implementations where multiple copies are produced by the interpreter with only a single pass over the data, the final value SHALL be equal to the value of the "job-k-octets" attribute. For implementations where multiple copies are produced by the interpreter by processing the data for each copy, the final value SHALL be a multiple of the value of the "job-k-octets" attribute. Note: This attribute and the following two attributes ("job- impressions-completed" and "job-sheets-completed") are intended to be counters. That is, if the "job-state" is 'processing' or 'processing- stopped', this value is intended to contain the amount of the job that has been processed to the time at which the attributes are requested. For any of these three attributes, the Printer may choose to return the value '-2' (which represents "unknown") rather than choose to not support the attribute at all. 4.3.17 job-impressions-completed (integer(0:2**31 - 1)) This job attribute specifies the number of impressions completed for the job so far. For printing devices, the impressions completed includes interpreting, marking, and stacking the output. This attribute is intended to be a counter as in the Job Monitoring MIB. For implementations where multiple copies are produced by the interpreter with only a single pass over the data, the final value SHALL be equal to the value of the "job-impressions" attribute. For implementations where multiple copies are produced by the interpreter by processing the data for each copy, the final value SHALL be a multiple of the value of the "job-impressions" attribute. 4.3.18 job-media-sheets-completed (integer(0:2**31 - 1)) This job attribute specifies the media-sheets completed marking and stacking for the entire job so far whether those sheets have been processed on one side or on both. This attribute is intended to be a counter as in the Job Monitoring MIB. 4.3.19 attributes-charset (charSet) This attribute is populated using the value in the client supplied "attributes-charset" attribute in the create request. It identifies deBry, Hastings, Herriot, Isaacson, Powell [Page 72] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 the charset (coded character set and encoding method) used for any Job attributes with attribute syntax 'text' and 'name' whether supplied by the client and/or returned by the Printer object. See Section 3.1.3 for a complete description of the "attributes-charset" operation attribute. 4.3.20 attributes-natural-language (naturalLanguage) 4.4 This attribute is populated using the value in the client supplied "attributes-natural-language" attribute in the create request. It identifies the natural language used for any Job attributes with attribute syntax 'text' and 'name' whether supplied by the client and/or returned by the Printer object. See Section 3.1.3 for a complete description of the "attributes-natural-language" operation attribute. See Section 4.1.1 for how an exception natural languages may be supplied explicitly for each 'text' and 'name' attribute value that differs from the value identified by the "job-natural-language" attribute.Printer Description Attributes These attributes form the attribute group called "printer- description". A Printer object may be realized in either a print server or output device. Note: How these attributes are set by an Administrator is outside the scope of this specification. The following table summarizes these attributes, their syntax, and whether or not they are MANDATORY for a Printer object to support. If they are not MANDATORY, they are OPTIONAL. deBry, Hastings, Herriot, Isaacson, Powell [Page 73] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 +----------------------------+----------------------+----------------+ | Attribute | Syntax | MANDATORY? | +----------------------------+----------------------+----------------+ | printer-uri | uri | MANDATORY | +----------------------------+----------------------+----------------+ | printer-name | name | MANDATORY | +----------------------------+----------------------+----------------+ | printer-location | text | | +----------------------------+----------------------+----------------+ | printer-info | text | | +----------------------------+----------------------+----------------+ | printer-more-info | uri | | +----------------------------+----------------------+----------------+ | printer-driver-installer | uri | | +----------------------------+----------------------+----------------+ | printer-make-and-model | text | | +----------------------------+----------------------+----------------+ | printer-more-info- | uri | | | manufacturer | | | +----------------------------+----------------------+----------------+ | printer-state | type1 enum | MANDATORY | +----------------------------+----------------------+----------------+ | printer-state-reasons | 1setOf type2 keyword | | +----------------------------+----------------------+----------------+ | printer-state-message | text | | +----------------------------+----------------------+----------------+ | operations-supported | 1setOf operation | MANDATORY | +----------------------------+----------------------+----------------+ | printer-charset | charSet | MANDATORY | +----------------------------+----------------------+----------------+ | charsets-supported | 1setOf charSet | MANDATORY | +----------------------------+----------------------+----------------+ | printer-natural-language | naturalLanguage | MANDATORY | +----------------------------+----------------------+----------------+ | natural-languages-supported| 1setOf | MANDATORY | | | naturalLanguage | | +----------------------------+----------------------+----------------+ | printer-is-accepting-jobs | boolean | MANDATORY | +----------------------------+----------------------+----------------+ | queued-job-count | integer | | +----------------------------+----------------------+----------------+ | printer-message-from- | text | | | operator | | | +----------------------------+----------------------+----------------+ | color-supported | boolean | | +----------------------------+----------------------+----------------+ | pdl-override | type2 keyword | MANDATORY | +----------------------------+----------------------+----------------+ deBry, Hastings, Herriot, Isaacson, Powell [Page 74] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 | security-mechanisms- | 1setOf keyword | | | supported | | | +----------------------------+----------------------+----------------+ | printer-up-time | integer | MANDATORY | +----------------------------+----------------------+----------------+ | printer-current-time | dateTime | | +----------------------------+----------------------+----------------+ | multiple-operation-time-out| integer | | +----------------------------+----------------------+----------------+ 4.4.1 printer-uri (uri) This attribute contains the URI for the printer. An administrator determines a printer's URI and sets this attribute to that URI. This MUST be an HTTP schemed URI, however the precise format of a printer URI is implementation dependent. 4.4.2 printer-name (name) This attribute contains the name of the printer. It is a name that is more user friendly than the printer-URI. An administrator determines a printer's name and sets this attribute to that name. This name may be the last part of the printer's URI or it may be unrelated. In non-US- English locales, a name may contain characters that are not allowed in a URI. 4.4.3 printer-location (text) This attribute identifies the location of this printer. This could include things like: _in Room 123A, second floor of building XYZ_. 4.4.4 printer-info (text) This attribute identifies the descriptive information about this Printer. This could include things like: "This printer can be used for printing color transparencies for HR presentations", or "Out of courtesy for others, please print only small (1-5 page) jobs at this printer", or even "This printer is going away on July 1, 1997, please find a new printer". 4.4.5 printer-more-info (uri) This attribute contains a URI used to obtain more information about this specific printer. For example, this could be an HTTP type URI referencing an HTML page accessible to a Web Browser. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI. The information is intended to be specific to this printer instance and deBry, Hastings, Herriot, Isaacson, Powell [Page 75] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 site specific services (e.g. job pricing, services offered, end user assistance). The device manufacturer may initially populate this attribute. 4.4.6 printer-driver-installer (uri) This attribute contains a URI to use to locate the driver installer for this printer. This attribute is intended for consumption by automata. The mechanics of print driver installation is outside the scope of IPP. The device manufacturer may initially populate this attribute. 4.4.7 printer-make-and-model (text) This attribute identifies the make and model of the printer. 4.4.8 printer-more-info-manufacturer (uri) This attribute contains a URI used to obtain more information about this type of printer. The information obtained from this URI is intended for end user consumption. Features outside the scope of IPP can be accessed from this URI (e.g., latest firmware, upgrades, print drivers, optional features available). The information is intended to be germane to this printer without regard to site specific modifications or services. The device manufacturer may initially populate this attribute. 4.4.9 printer-state (type1 enum) This attribute identifies the current state of the printer. The "printer-state reasons" attribute augments the "printer-state" attribute to give more detailed information about the Printer in the given printer state. A Printer object need only update this attribute before responding to an operation which requests the attribute; the Printer object NEED NOT update this attribute continually. A Printer NEED NOT implement all values if they are not applicable to a given implementation. The following standard values are defined: 'unknown'(2): The Printer state is not known, or is indeterminate. A Printer SHALL use this state only if it cannot determine its actual state. 'idle'(3): If a Printer receives a job (whose required resources are ready) while in this state, such a job SHALL transit into the processing state immediately. If the printer-state-reasons deBry, Hastings, Herriot, Isaacson, Powell [Page 76] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 attribute contains any reasons, they SHALL be reasons that would not prevent a job from transiting into the processing state immediately, e.g., toner-low. Note: if a Printer controls more than one output device, the above definition implies that a Printer is idle if at least one output device is idle. 'processing'(4): If a Printer receives a job (whose required resources are ready) while in this state, such a job SHALL transit into the pending state immediately. Such a job SHALL transit into the processing state only after jobs ahead of it complete. If the printer-state-reasons attribute contains any reasons, they SHALL be reasons that do not prevent the current job from printing, e.g. toner-low. Note: if a Printer controls more than one output device, the above definition implies that a Printer is processing if at least one output device is processing, and none is idle. 'stopped'(5): If a Printer receives a job (whose required resources are ready) while in this state, such a job SHALL transit into the pending state immediately. Such a job SHALL transit into the processing state only after some human fixes the problem that stopped the printer and after jobs ahead of it complete printing. The "printer-state-reasons" attribute SHALL contain at least one reason, e.g. media-jam, which prevents it from either processing the current job or transiting a pending job to the processing state. Note: if a Printer controls more than one output device, the above definition implies that a Printer is stopped only if all output devices are stopped. Also, it is tempting to define stopped as when a sufficient number of output devices are stopped and leave it to an implementation to define the sufficient number. But such a rule complicates the definition of stopped and processing. For example, with this alternate definition of stopped, a job can move from idle to processing without human intervention, even though the Printer is stopped. 4.4.10 printer-state-reasons (1setOf type2 keyword) This attribute supplies additional detail about the printer's state. Each MAY have a suffix to indicate its level of severity. The three levels are: report (least severe), warning, and error (most severe). - '-report': This suffix indicates that the reason is a "report". An implementation may choose to omit some or all reports. Some reports specify finer granularity about the printer state; others deBry, Hastings, Herriot, Isaacson, Powell [Page 77] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 serve as a precursor to a warning. A report SHALL contain nothing that could affect the printed output. - '-warning': This suffix indicates that the reason is a "warning". An implementation may choose to omit some or all warnings. Warnings serve as a precursor to an error. A warning SHALL contain nothing that prevents a job from completing, though in some cases the output may be of lower quality. - '-error': This suffix indicates that the reason is an "error". An implementation SHALL include all errors. If this attribute contains one or more errors, printer SHALL be in the stopped state. If the implementation does not add any one of the three suffixes, all parties SHALL assume that the reason is an "error". If a Printer object controls more than one output device, each value of this attribute MAY apply to one or more of the output devices. An error on one output device that does not stop the Printer object as a whole MAY appear as a warning in the Printer's "printer-state-reasons attribute". If the "printer-state" for such a Printer has a value of 'stopped', then there MUST be an error reason among the values in the "printer-state-reasons" attribute. The following standard values are defined: 'other': The printer has detected an error other than one listed in this document. 'unknown': The printer is unable to give additional detail about the state of the printer. This state reason is semantically equivalent to printer-state-reasons without any value. 'media-needed': A tray has run out of media. 'media-jam': The printer has a media jam. 'paused': Someone has paused the Printer. In this state, a Printer SHALL not produce printed output, but it SHALL perform other operations requested by a client. If a Printer had been printing a job when the Printer was paused, the Printer SHALL resume printing that job when the Printer is no longer paused and leave no evidence in the printed output of such a pause. 'shutdown': Someone has removed a Printer from service, and it may be powered down or physical removed. In this state, a Printer SHALL not produce printed output, and unless the Printer is realized by a print server that is still active, the Printer SHALL perform no other operations requested by a client, including returning this value. If a Printer had been printing a job when it was shutdown, the Printer need not resume printing that job when the Printer is no longer shutdown. If the Printer resumes printing such a job, it may leave evidence in the printed deBry, Hastings, Herriot, Isaacson, Powell [Page 78] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 output of such a shutdown, e.g. the part printed before the shutdown may be printed a second time after the shutdown. 'connecting-to-device': The server has scheduled a job on the Printer and is in the process of connecting to a shared network output device (and might not be able to actually start printing the job for an arbitrarily long time depending on the usage of the output device by other servers on the network). 'timed-out': The server was able to connect to the output device (or is always connected), but was unable to get a response from the output device. 'stopping': The printer will be stopping in a while and will change its reason to printer-stopped. This reason is a non-critical, even for a Printer with a single output device. When an output- device ceases accepting jobs, the Printer will have this reason while the output device completes printing. 'stopped-partly': When a Printer controls more than one output device, this reason indicates that one or more output devices are stopped. If the reason is a report, fewer than half of the output devices are stopped. If the reason is a warning, fewer than all of the output devices are stopped. 'toner-low': The Printer is low on toner. 'marker-supply-low': The Printer is low on marker supply (ink, paint, etc.). 'spool-area-full': The limit of persistent storage allocated for spooling has been reached. 'cover-open': One or more covers on the printer is open. 'interlock-open': One or more interlock devices on the printer is unlocked. 'door-open': One or more doors on the printer are open. 'input-tray-missing': One or more input trays are not in the printer. 'media-low': At least one input tray is low on media. 'media-empty': At least one input tray is empty. 'output-tray-missing': One or more output trays are not in the printer 'output-area-almost-full': One or more output area is almost full (e.g. tray, stacker, collator). 'output-area-full': One or more output area is full. (e.g. tray, stacker, collator) 'marker-supply-low': The Printer is low on at least one marker supply. (e.g. toner, ink, ribbon) 'marker-supply-empty: The Printer is out of at least one marker supply. (e.g. toner, ink, ribbon) 'marker-waste-almost-full': The Printer marker supply waste receptacle is almost full. 'marker-waste-full': The Printer marker supply waste receptacle is full. 'fuser-over-temp': The fuser temperature is above normal. deBry, Hastings, Herriot, Isaacson, Powell [Page 79] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'fuser-under-temp': The fuser temperature is below normal. 'opc-near-eol': The optical photo conductor is near end of life. 'opc-life-over': The optical photo conductor is no longer functioning. 'developer-low': The Printer is low on developer. 'developer-empty: The Printer is out of developer. 'interpreter-resource-unavailable': An interpreter resource is unavailable (i.e. font, form) 4.4.11 printer-state-message (text) This attribute specifies the additional information about the printer state and printer state reasons in human readable text. The Printer object SHALL be able to generate this message in any of the natural languages identified by the Printer's "natural-language-supported" attribute (see the "attributes-natural-language" operation attribute specified in Section 3.1.3.1). 4.4.12 operations-supported (1setOf operation) This attribute specifies the set of supported operations for this Printer. The syntax of type of "operation" is the same as "type2 enum" except that the range of values is 0x0000 to 0x8FFF. The following standard values are defined: 0x0000 reserved, not used 0x0001 reserved, not used 0x0002 Print-Job 0x0003 Print-URI 0x0004 Validate-Job 0x0005 Create-Job 0x0006 Send-Document 0x0007 Send-URI 0x0008 Cancel-Job 0x000A Get-Jobs 0x0009 Get-Attributes 0x000A-0x3FFF reserved for future operations 0x4000-0x8FFF reserved for private extensions This allows for certain vendors to implement private extensions that are guaranteed to not conflict with future registered extensions. However, there is no guarantee that two or more private extensions will not conflict. deBry, Hastings, Herriot, Isaacson, Powell [Page 80] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.4.13 printer-charset (charSet) This MANDATORY attribute identifies the charset that the Printer object has been configured to represent 'text' and 'name' Printer attributes that are set by the operator, system administrator, or manufacturer, i.e., for "printer-name" (name), "printer-location" (text), "printer-info" (text), and "printer-make-and-model" (text). Therefore, the value of the "printer-charset" attribute SHALL also be among the values of the Printer's "charset-supported" attribute. 4.4.14 charsets-supported (1setOf charSet) This MANDATORY attribute identifies the set of charsets that the Printer object supports in attributes with attribute syntax 'text' and 'name', i.e., that the Printer object SHALL (1) accept in requests, (2) return in responses, and (3) send in notification messages. At least the value 'utf-8' SHALL be present, since a Printer object SHALL support the UTF-8 [RFC2044] charset. If more charsets than UTF-8 are supported, the Printer object SHALL perform charset conversion between the charsets as described in Section 3.1.3.1. 4.4.15 printer-natural-language (naturalLanguage) This MANDATORY attribute identifies the natural language that the Printer object has been configured to represent 'text' and 'name' Printer attributes that are set by the operator, system administrator, or manufacturer, i.e., for "printer-name" (name), "printer-location" (text), "printer-info" (text), and "printer-make-and-model" (text). When returning these Printer attributes, the Printer object MAY return them in the configured natural language specified by this attribute, instead of the natural language requested by the client in the "attributes-natural-language" operation attribute. See Section 3.1.3.1 for the specification of the OPTIONAL multiple natural language support. Therefore, the value of the "printer-natural- language" attribute SHALL also be among the values of the Printer's "natural-language-supported" attribute. 4.4.16 natural-languages-supported (1setOf naturalLanguage) This MANDATORY attribute identifies the natural language(s) that the Printer object supports in attributes with attribute syntax 'text' and 'name', i.e., that the Printer object SHALL (1) accept in requests, (2) return in responses, and (3) send in notification messages. The natural language(s) supported depends on implementation and/or configuration. deBry, Hastings, Herriot, Isaacson, Powell [Page 81] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 For any of the attributes for which the Printer generates messages, i.e., for the "job-state-message" and "printer-state-message" attributes and Operation Messages (see Section 3.1.4) in operation responses, the Printer object SHALL be able to generate messages in any of its supported natural languages. See section 3.1.3.1 for the specification of 'text' and 'name' attributes in operation requests and responses. Note: A Printer object that supports multiple natural languages, often has separate catalogs of messages, one for each natural language supported. 4.4.17 printer-is-accepting-jobs (boolean) This attribute indicates whether the printer is currently accepting job. If the value is true, the printer is accepting jobs. If the value is false, the printer is currently rejecting any jobs submitted to it. Note: This value is independent of the printer state and printer- state-reasons because its value does not affect the current job; rather it affects future jobs. This attribute may cause the Printer to reject jobs when the printer-state is idle or it may cause the Printer to accepts jobs when the printer-state is stopped. 4.4.18 queued-job-count (integer(0:2**31 - 1)) This attribute contains a count of the number of jobs that are either 'pending', 'processing', 'pending-held', or 'processing-stopped' and is set by the Printer. 4.4.19 printer-message-from-operator (text) This attribute provides a message from an operator, system administrator or "intelligent" process to indicate to the end user information or status of the printer, such as why it is unavailable or when it is expected to be available. 4.4.20 color-supported (boolean) This attribute identifies whether the Printer is capable of any type of color printing at all. All document instructions having to do with color are embedded within the document PDL (none are external IPP attributes). deBry, Hastings, Herriot, Isaacson, Powell [Page 82] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.4.21 reference-uri-schemes-supported (1setOf uriScheme) This attribute specifies which URI schemes are supported for use in the "document-uri" operation attribute of the Print-URI or Send-URI operation. If a Printer object supports these optional operations, it MUST support URIs of the following type: 'http': The Printer object will perform an HTTP/1.1 GET operation 'ftp': The Printer object will use an FTP 'get' operation. If the URI does not indicate a name or password in the URI itself, the Printer object will use anonymous FTP generating (if prompted) some password in the form of an Internet mail address. The Printer object OPTIONALLY supports other URI schemes (see section 4.1.6). 4.4.22 pdl-override (type2 keyword) This attribute expresses the ability for a particular Printer implementation to either attempt to override document data instructions with IPP attributes or not. This MANDATORY attribute takes on the following values: - 'attempted': This value indicates that the Printer attempts to make sure that IPP attribute values take precedence over embedded instructions in the document data, however there is no guarantee. - 'not-attempted': This value indicates that the Printer makes no attempt to ensure that IPP attribute values take precedence over embedded instructions in the print data. Section 15 contains a full description of how this attribute interacts with and affects other IPP attributes, especially the "ipp-attribute- fidelity" attribute. 4.4.23 security-mechanisms-supported (1setOf keyword) This attribute indicates the security mechanisms supported. Standard values are: 'tls': Transport Layer Security (TLS) 'ssl': Secure Sockets Layer (SSL) 'http-digest': HTTP/1.1 Digest Authentication 'http-basic': HTTP/1.1 Basic Authentication deBry, Hastings, Herriot, Isaacson, Powell [Page 83] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 4.4.24 printer-up-time (integer(1:MAX)) This attribute is a MANDATORY attribute. It indicates the amount of time (in seconds) that this instance of this Printer implementation has been up and running. This value is used to populate the Job attributes "time-of-creation", "time-at-processing", and "time-at- completed". These time values are all measured in seconds and all have meaning only relative to this attribute, "printer-up-time". The value is a monotonically increasing value starting from 1 when the Printer object is started-up (initialized, booted, etc.). If the Printer object goes down at some value 'n', and comes back up, the implementation MAY: 1. Know how long it has been down, and resume at some value greater than 'n', or 2. Restart from 1. In the first case, the Printer SHOULD not tweak any existing related Job attributes ("time-of-creation", "time-at-processing", and "time- at-completed"). In the second case, the Printer object SHOULD be reset to 0. If a client queries a time-related Job attribute and finds the value to be 0, the client MUST assume that the Job was submitted in some life other than the Printer's current life. 4.4.25 printer-current-time (dateTime) This attribute is an OPTIONAL attribute. It indicates the current absolute wall-clock time. If an implementation supports this attribute, then a client could calculate the absolute wall-clock time each Job's "time-of-creation", "time-at-processing", and "time-at- completed" attributes by using both "printer-up-time" and this attribute, "printer-current-time". If an implementation does not support this attribute, a client can only calculate the relative time of certain events based on the MANDATORY "printer-up-time" attribute. 4.4.26 multiple-operation-time-out (integer) This attributes identifies how long (in seconds) the Printer object waits for additional Send-Document or Send-URI operations to follow a still-open multi-document Job object. 5. Conformance This section describes conformance issues and requirements. This document introduces model entities such as objects, operations, deBry, Hastings, Herriot, Isaacson, Powell [Page 84] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 attributes, and attribute values. These conformance sections describe the conformance requirements which apply to these model entities. 5.1 Client Conformance Requirements A conforming client SHALL send operations that conform to the protocol defined in _Internet Printing Protocol/1.0: Protocol Specification_ [IPP-PRO]. For each attribute included in an operation request, a conforming client SHALL send a value whose type and value syntax conforms to the requirement of this document Otherwise, there are no conformance requirements placed on the user interfaces provided by IPP clients or their applications. For example, one application might not allow an end user to submit multiple documents per job, while another does. One application might first query a Printer object in order to supply a graphical user interface (GUI) dialogue box with supported and default values whereas a different implementation might not. For presentation purposes, truncation of long attribute values is not recommended. A recommended approach would be for the client implementation to allow the user to scroll through long attribute values. When sending a Get-Attributes or create request, an IPP client NEED NOT supply any OPTIONAL attributes. A client SHALL be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, that may be returned to it in a response from a Printer object. A query response may contain attributes and values that the client does not expect. Therefore, a client implementation MUST gracefully handle such responses and not refuse to inter-operate with a conforming Printer that is returning extended registered or private attributes and/or attribute values that conform to Section 6. Clients may choose to ignore any parameters, attributes, or values that it does not understand. 5.2 Printer Object Conformance Requirements This section specifies the conformance requirements for conforming Printer object implementations with respect to objects, operations, and attributes. deBry, Hastings, Herriot, Isaacson, Powell [Page 85] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 5.2.1 Objects Conforming Printer implementations SHALL implement all of the model objects as defined in this specification in the indicated sections: Section 2.1 Printer Object Section 2.2 Job Object 5.2.2 Operations Conforming Printer implementations SHALL implement all of the MANDATORY model operations, including mandatory responses, as defined in this specification in the indicated sections: For a Printer object: Print-Job (section 3.2.1) MANDATORY Print-URI (section 3.2.2) OPTIONAL Validate-Job (section 3.2.3) MANDATORY Create-Job (section 3.2.4) OPTIONAL Get-Attributes (section 3.2.5) MANDATORY Get-Jobs (section 3.2.6) MANDATORY For a Job object: Send-Document (section 3.3.1) OPTIONAL Send-URI (section 3.3.2) OPTIONAL Cancel-Job (section 3.3.3) MANDATORY Get-Attributes (section 3.3.4) MANDATORY Conforming Printer implementations SHALL support all operation attributes and all values of such attributes, except for attributes that are collections of attributes. The following section on attributes specifies the support required for attributes. 5.2.3 Attributes Conforming Printer implementations SHALL support all of the MANDATORY attributes, as defined in this specification in the indicated sections. If a Printer supports an attribute, it SHALL support only those values specified in this document or through the extension mechanism described in the next section. It MAY support any non-empty subset of these values. That is, it SHALL support at least one of the specified values and at most all of them. deBry, Hastings, Herriot, Isaacson, Powell [Page 86] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 5.2.4 Printer extensions A conforming Printer may support registered extensions and private extensions, as long as they meet the requirements specified in Section 6. A conforming Printer SHALL send responses that conform to the protocol defined in _Internet Printing Protocol/1.0: Protocol Specification_ [IPP-PRO]. For each attribute included in an operation response, a conforming printer SHALL send a value whose type and value syntax conforms to the requirement of this document 5.2.5 Attribute Syntaxes A Printer SHALL be able to accept any of the attribute syntaxes defined in Section 4.1, including their full range, in any operation in which a client may supply attributes. Furthermore, a Printer SHALL return attributes to the client in operation responses that conform to the syntax specified in Section 4.1, including their full range if supplied previously by a client. 5.3 Security Conformance Requirements All clients and IPP objects SHALL support the two authentication mechanisms for HTTP/1.1 as defined in RFC 2068 [RFC2068] and RFC 2069 [RFC2069]. Clients and IPP objects that need mutual authentication and/or encryption SHOULD also support a secure connection protocol. For this purpose it is the intention to define standardization of IPP in combination with Transport Layer Security (TLS), when the TLS specifications are agreed and on the IETF standards track. For a detailed discussion of security considerations, see section 8. 6. IANA Considerations (registered and private extensions) During the development of this standard, the IPP working group (working with IANA) will register additional keywords and enums while the standard is in the proposed and draft states according to the procedures described in this section. IANA will handle registration of additional enums after this standard is approved in cooperation with an IANA-appointed registration editor from the IPP working group according to the procedures described in this section. deBry, Hastings, Herriot, Isaacson, Powell [Page 87] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 6.1 Typed Extensions This document uses prefixes to the "keyword" and "enum" basic syntax type in order to communicate extra information to the reader through its name. This extra information need not be represented in an implementation because it is unimportant to a client or Printer. The list below describes the prefixes and their meaning. "type1": The IPP standard must be revised to add a new keyword or a new enum. No private keywords or enums are allowed. "type2": Implementers can, at any time, add new keyword or enum values by proposing the specification to the IPP working group for registration (or an IANA-appointed registry advisor after the IPP working group is no longer certified) where they are reviewed for approval. IANA keeps the registry and assigned the number for enum values "type3": Implementers can, at any time, add new keyword and enum values by submitting the complete specification directly to IANA, no IPP working group or IANA-appointed registry advisor review is required. IANA keeps the registry and assigned the number for enum values "type4": Anyone (system administrators, system integrators, site managers, etc.) can, at any time, add new installation-defined values (keywords or new enum values) to a local system. Care SHOULD be taken by the implementers to see that keywords do not conflict with other keywords defined by the standard or as defined by the implementing product. There is no registration or approval procedure for type 4 keywords. By definition, each of the four types above assert some sort of registry or review process in order for extensions to be considered valid. Each higher level (1, 2, 3, 4) tends to be decreasingly less stringent than the previous level. Therefore, any typeN value MAY be registered using a process for some typeM where M is less than N, however such registration is NOT REQUIRED. For example, a type4 value MAY be registered in a type 1 manner (by being included in a future version of an IPP specification) however it is NOT REQUIRED. This specification defines keyword and enum values for all of the above types, including type4 keywords. For private (unregistered) keyword extensions, implementers SHOULD use keywords with a suitable distinguishing prefix, such as "xxx-" where xxx is the (lowercase) fully qualified company name registered with IANA for use in domain names [RFC1035]. deBry, Hastings, Herriot, Isaacson, Powell [Page 88] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Note: RFC 1035 [RFC1035] indicates that while upper and lower case letters are allowed in domain names, no significance is attached to the case. That is, two names with the same spelling but different case are to be treated as if identical. Also, the labels in a domain name must follow the rules for ARPANET host names: They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen. Labels must be 63 characters or less. Labels are separated by the "." character. For private (unregistered) enum extension, implementers SHOULD use values in the reserved integer range which is 2**30 to 2**31-1. 6.2 Registration of MIME types/sub-types for document-formats The "document-format" attribute's syntax is "mimeType". This means that valid values are Internet media types. RFC 2045 [RFC2045] defines the syntax for valid Internet media types. Also, IANA is the registry for all Internet media types. 6.3 Attribute Extensibility Attribute names are considered to be set of type2 keywords. Therefore, new attributes may be registered and have the same status as attributes in this document by following the type2 extension rules. 6.4 Attribute Syntax Extensibility Attribute syntaxes are considered to be set of type2 enums. Therefore, new attribute syntaxes may be registered and have the same status as attribute syntaxes in this document by following the type2 extension rules. 7. Internationalization Considerations Some of the attributes have values that are text strings and names intended for human understanding rather than machine understanding. See the 'text' and 'name' attribute syntaxes in Sections 4.1.1 and 4.1.2. In each operation request, the client SHALL identify the charset and natural language of the request which affects each supplied 'text' and 'name' attribute value and requests the charset and natural language for attributes returned by the Printer object in operation responses and notifications as described in Section 3.1.3.1. In addition, the deBry, Hastings, Herriot, Isaacson, Powell [Page 89] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 client MAY separately and individually identify the "exception" natural language of a supplied 'text' or 'name' attribute using the technique described for the 'text' attribute syntax in Section 4.1.1. The Printer object SHALL support the UTF-8 [RFC2044] charset in all 'text' and 'name' attributes supported. If the Printer object supports more than the UTF-8 charset, the Printer object SHALL convert between them in order to return the requested charset to the client according to Section 3.1.3.2. If the Printer object supports more than one natural language, the Printer object SHOULD return 'text' and 'name' values in the natural language requested for those that are generated by the Printer (see Section 3.1.3.1). For Printers that support multiple charsets and/or multiple natural languages in 'text' and 'name' attributes, different jobs may have been submitted in differing charsets and/or natural languages. All responses SHALL be returned in the charset requested by the client. However, the Get-Jobs operation provides for a mechanism to identify the differing natural languages with each job returned. The Printer object also has a configured charset and natural language attribute that it uses when the requested charset or natural language are not supported. The client can query the Printer object to determine the list of charsets and natural languages supported by the Printer object and what the Printer object's configured values are. See the "printer-charset", "charset-supported", "printer-natural- language", and "natural-language-supported" Printer description attributes. The 'text' and 'name' attributes specified in this version of this document (additional ones will be registered according to the procedures in Section 6) are: Operation Attributes: job-name (name) document-name (name) Job Attributes: job-name (name) job-originating-user (name) job-state-message (text) job-message-from-operator (text) Printer Attributes: printer-name (name) printer-location (text) deBry, Hastings, Herriot, Isaacson, Powell [Page 90] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 printer-info (text) printer-make-and-model (text) printer-state-message (text) printer-message-from-operator (text) 8. Security Considerations It is required that the IPP be able to operate within a secure environment. IPP attempts to make use of existing security protocols and services, wherever possible. Examples of such services include the Digest Access Authentication in HTTP 1.1 [RFC2069] and the Transport Layer Security (TLS) services, currently under development in the IETF. It is difficult to anticipate the security risks that might exist in any given IPP environment. For example, if IPP is used within a given corporation over a private network, the risks of exposing document data may be low enough that the corporation will choose not to use encryption on that data. However, if the connection between the client and the IPP object is over a public network, the client may wish to protect the content of the information during transmission through the network with encryption. Furthermore, the value of the information being printed may vary from one use of the protocol to the next. Printing payroll checks, for example, would have a different value than printing public information from a file. In addition, there is always the threat of a virus attack. However, there are no known viruses or potential for viruses that are self-propagated throughout distributed printing environments. Therefore, IPP implementations may choose to implement protection against printer-damaging print jobs. Since the security levels or the specific threats that any given IPP print administrator may be concerned with cannot be anticipated, IPP MUST be capable of operating with different security mechanisms and security policies as required by the individual installation. Security policies might vary from very strong, to very weak, to none at all, and corresponding security mechanisms will be required. The initial security needs of IPP are derived from two primary considerations: - First, the printing environments envisioned for IPP include configurations where the client, the Printer, and the document(s) to be printed may all exist in different security domains. When objects are in different security domains the requirements for deBry, Hastings, Herriot, Isaacson, Powell [Page 91] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 authentication and message protection are much stronger than when they are in the same domain. - Second, the sensitivity and value of the content being printed will vary. For example, a publicly available document does not require the same level of privacy that a payroll document requires. There are at least two parties that have an interest in the value of the information being printed, the person asking to have the information printed and the person who originated the information. This brings into the picture the need to worry about copyrights and protection of the content. The following sections describe specific security attacks for IPP environments. Where examples are provided they should be considered illustrative of the environment and not an exhaustive set. Not all of these environments will necessarily be addressed in initial implementations of IPP. 8.1 Client and Printer in the Same Security Domain This environment is typical of internal networks where traditional office workers print the output of personal productivity applications on shared work-group printers, or where batch applications print their output on large production printers. Although the identity of the user may be trusted in this environment, a user might want to protect the content of a document against such attacks as eavesdropping, replaying or tampering. 8.2 Client and Printer in Different Security Domains Examples of this environment include printing a document created by the client on a publicly available printer, such as at a commercial print shop; or printing a document remotely on a business partner's printer. This latter operation is functionally equivalent to sending the document to the business partner as a facsimile. Printing sensitive information on a Printer in a different security domain requires strong security measures. In this environment authentication of the printer is required as well as protection against unauthorized use of print resources. Since the document crosses security domains, protection against eavesdropping and document tampering are also required. It will also be important in this environment to protect Printers against "spamming" and malicious document content code. deBry, Hastings, Herriot, Isaacson, Powell [Page 92] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 8.3 Print by Reference When the document is not stored on the client, printing can be done by reference. That is, the print request can contain a reference, or pointer, to the document instead of the actual document itself. If the client physically gets the document before it prints it, then this defaults to one of the previous cases. 8.3.1 Unprotected Documents In many cases, documents to be printed are literally available to anyone. Documents, such as this Internet Draft which are stored on anonymous FTP sites, are good examples of this. No security mechanisms are required to protect access to these documents. 8.3.2 Protected Documents Clearly, there are cases where the nature of a document requires that access to it be protected by some authentication and/or authorization mechanism, or where the right to print the document must be paid for. This would be the case for sensitive or confidential information, or where documents are copyrighted or sold for profit. Unauthorized access to content is a major concern in this environment. Protection against eavesdropping, document tampering and unauthorized access to the document are also concerns if the content is sensitive. 8.4 Common Security Scenarios As discussed earlier, we cannot anticipate the security levels or the specific threats that any given IPP print administrator may be concerned with. Security policies might vary from very strong, to very weak, to none at all. In this section we will describe what we believe to be four common usage scenarios. 1) No security at all 2) Message protection during transmission 3) Client authentication and authorization 4) Mutual authentication, authorization, and message protection 8.4.1 No Security If the server requires no authorization and the client wants no message protection the client can send the print job, i.e., the job content and the job attributes without invoking any security mechanisms. The printer will print the job for the client. Print by deBry, Hastings, Herriot, Isaacson, Powell [Page 93] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 reference also works well in this environment as long as no security mechanisms are required to access the documents to be printed. 8.4.2 Message Protection During Transmission There are two types of security that could be used to provide message protection. These are channel security and object security. In the first case, the channel can be made secure using the Transport Layer Security (TLS) protocol, currently under development in the IETF. In the case of object security, each object is encrypted and sent over either a secure or insecure channel. The recipient has the corresponding key to decrypt the object and get the content. Several object security mechanisms are currently under study in the IETF. IPP neither mandates the use of these object security mechanisms nor does it prohibit the use of them. IPP will define a recommended mechanism for channel security, which is deemed more suitable to meet the IPP requirements. 8.4.3 Client Authentication and Authorization This scenario requires client authentication. The authenticated user ID may be used for authorization purposes, and may be encrypted by the lower security layer. TLS supports both one sided and mutual authentication. IPP does not mandate the use of any specific authorization mechanism (see section 3.1.5.1). 8.4.4 Mutual Authentication, Authorization and Message Protection This scenario requires mutual authentication and message protection. TLS can be used for this security feature in these configurations. 8.5 Recommended Security Mechanisms IPP requires all IPP clients and Printers to support the authentication features in HTP 1.1 and intends to mandate TLS for scenarios requiring channel security, once these specifications have become stabilized. IPP implementations should provide a range of security options to meet the needs of different installations and user populations. Many of the security services that are enabled at a given site will be done so by a site administrator. The mechanisms used to establish these services and to define user IDs and passwords to the system are implementation defined and outside the scope of IPP. The security protocol used by a particular IPP operation will depend upon the security services implemented on the Printer, the security deBry, Hastings, Herriot, Isaacson, Powell [Page 94] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 policy established by a site administrator, and the selection made by the client. This requires that the right handshake messages be passed to invoke the selected security service. These are described in the references for each security mechanism and are normally invoked by the client. The "security-mechanisms-supported" and "printer-more-info" attributes can be queried to help the end user know what to expect in terms of security. These attributes should also appear in the directory entry for each Printer. Note: When utilizing HTTP/1.1 as a transport for IPP [IPP-PRO], the security considerations outlined in HTTP/1.1 apply. When set by an administrator, IPP servers MUST generate a 401 (Unauthorized) response code to request client authentication and IPP clients should correctly respond with the proper Authorization header. Both basic authentication and digest authentication flavors of authentication should be supported. The administrator chooses which type(s) of authentication to accept. Digest authentication is a more secure method and is always preferred to basic authentication. For secure communication (privacy in particular), IPP should be run using a secure communications channel. TLS provides secure communications channels and provides for mutual authentication. The secure communications channel must be initiated prior to running the IPP protocol. There is no mechanism for bootstrapping a secure communication channel from within the IPP protocol itself. It is possible to combine a secure communication channel with either Basic or Digest Authentication. For a Printer object that supports only non-secure access, the Printer object supports only the "printer-uri" attribute. For a Printer object that supports only secure access, the Printer object supports only the "printer-tls-uri". For a Printer object that supports both secure and non-secure access, the Printer object supports both the "printer-uri" and the "printer-tls-uri" attributes. 9. References [ASCII] Coded Character Set - 7-bit American Standard Code for Information Interchange (ASCII), ANSI X3.4-1986. This standard is the specification of the 'US-ASCII' charset. [CS-POL] H. Alvestrand, "IETF Policy on Character Sets and Languages, work in progress <draft-alvestrand-charset-policy-01.txt>, August 29, 1997. deBry, Hastings, Herriot, Isaacson, Powell [Page 95] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 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). [IANA-MT] IANA Registry of Media Types: ftp://ftp.isi.edu/in- notes/iana/assignments/media-types/ [IPP-PRO] Herriot, R. (et al), " Internet Printing Protocol/1.0: Protocol Specifications", draft-ipp-pro-03.txt, November, 1997. [IPP-RAT] Zilles, S., "Rationale for the Structure and Model and Protocol for the Internet Printing Protocol", draft-ipp-rat-01.txt, November, 1997. [IPP-REQ] Wright, D., "Requirements for an Internet Printing Protocol", draft-ipp-req-01.txt, November, 1997. [ISO10646-1] ISO/IEC 10646-1:1993, "Information technology -- Universal Multiple-Octet Coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual Plane, JTC1/SC2." [ISO8859-1] ISO/IEC 8859-1:1987, "Information technology -- 8-bit One-Byte Coded Character Set - Part 1: Latin Alphabet Nr 1", 1987, JTC1/SC2. [ISODPA] ISO/IEC 10175 Document Printing Application (DPA), June 1996. [LDPA] T. Hastings, S. Isaacson, M. MacKay, C. Manros, D. Taylor, P. Zehler, "LDPA - Lightweight Document Printing Application", October 1996, ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/ldpa8.pdf.gz deBry, Hastings, Herriot, Isaacson, Powell [Page 96] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 [P1387.4] Kirk, M. (editor), POSIX System Administration - Part 4: Printing Interfaces, POSIX 1387.4 D8, 1994. [PSIS] Herriot, R. (editor), X/Open A Printing System Interoperability Specification (PSIS), August 1995. [RFC1035] P. Mockapetris, "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION", RFC 1035, November 1987. [RFC1179] McLaughlin, L. III, (editor), "Line Printer Daemon Protocol" RFC 1179, August 1990. [RFC1514] ?, " ", RFC 1514, ?. [RFC1521] Borenstein, N., and Freed, N., "MIME (Multi-purpose Internet Mail Extensions) Part One: Mechanism for Specifying and Describing the Format of Internet Message Bodies", RFC 1521, September, 1993. [RFC1630] T. Berners-Lee, "Universal Resource Identifiers in WWW: A Unifying Syntax for the Expression of Names and Addresses of Objects on the Network as used in the World-Wide Web", RFC 1630, June 1994. [RFC1738] Berners-Lee, T., Masinter, L., McCahill, M. , "Uniform Resource Locators (URL)", RFC 1738, December, 1994. [RFC1759] Smith, R., Wright, F., Hastings, T., Zilles, S., and Gyllenskog, J., "Printer MIB", RFC 1759, March 1995. [RFC1766] H. Alvestrand, " Tags for the Identification of Languages", RFC 1766, March 1995. [RFC1808] ?, " ", RFC 1808, ?. [RFC1825] R. Atkinson, "Security Architecture for the Internet Protocol", RFC 1825, August 1995 deBry, Hastings, Herriot, Isaacson, Powell [Page 97] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 [RFC1903] ?, " ", RFC 1903, ?. [RFC2044] F. Yergeau, "UTF-8, a transformation format of Unicode and ISO 10646", RFC 2044, October 1996. [RFC2068] R. Fielding, J. Gettys, J. Mogul, H. Frystyk, T. Berners-Lee, "Hypertext Transfer Protocol - HTTP/1.1", RFC 2068, January 1997 [RFC2069] J. Franks, P. Hallam-Baker, J. Hostetler, P. Leach, A. Luotonen, E. Sink, L. Stewart, "An Extension to HTTP: Digest Access Authentication", RFC-2069, Jan 1997. [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119 , March 1997 [RFC2130] ?, " ", RFC 2130, ?. [RFC2045] N. Fried, N. Borenstein, ", Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies " RFC 2045, November 1996. [RFC2046] Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types. N. Freed & N. Borenstein. November 1996. (Obsoletes RFC1521, RFC1522, RFC1590), RFC 2046. [RFC2048] Multipurpose Internet Mail Extension (MIME) Part Four: Registration Procedures. N. Freed, J. Klensin & J. Postel. November 1996. (Format: TXT=45033 bytes) (Obsoletes RFC1521, RFC1522, RFC1590) (Also BCP0013), RFC 2048. [RFC2184] N. Fried, K. Moore, "MIME Parameter Value and Encoded Word Extensions: Character Sets, Languages, and Continuations", RFC 2184, August 1997 [SWP] P. Moore, B. Jahromi, S. Butler, "Simple Web Printing SWP/1.0", May 7, 1997, ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/swp9705.pdf deBry, Hastings, Herriot, Isaacson, Powell [Page 98] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 10. Copyright Notice Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 11. Author's Address Scott A. Isaacson (Editor) Novell, Inc. 122 E 1700 S Provo, UT 84606 Phone: 801-861-7366 Fax: 801-861-4025 EMail: scott_isaacson@novell.com Tom Hastings Xerox Corporation 701 S. Aviation Blvd. El Segundo, CA 90245 deBry, Hastings, Herriot, Isaacson, Powell [Page 99] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Phone: 310-333-6413 Fax: 310-333-5514 EMail: hastings@cp10.es.xerox.com Robert Herriot Sun Microsystems Inc. 901 San Antonio.Road, MPK-17 Palo Alto, CA 94303 Phone: 415-786-8995 (Area code change to 650 in August 1997) Fax: 415-786-7077 (Area code change to 650 in August 1997) Email: robert.herriot@eng.sun.com Roger deBry HUC/003G IBM Corporation P.O. Box 1900 Boulder, CO 80301-9191 Phone: (303) 924-4080 Fax: (303) 924-9889 Email: debry@vnet.ibm.com Patrick Powell San Diego State University 9475 Chesapeake Dr., Suite D San Diego, CA 95123 Phone: (619) 874-6543 Fax: (619) 279-8424 Email: papowell@sdsu.edu IPP Mailing List: ipp@pwg.org IPP Mailing List Subscription: ipp-request@pwg.org IPP Web Page: http://www.pwg.org/ipp/ Other Participants: Chuck Adams - Tektronix Jeff Barnett - IBM Ron Bergman - Dataproducts Corp. Sylvan Butler, HP Keith Carter, IBM Corporation Jeff Copeland - QMS Andy Davidson - Tektronix Mabry Dozier - QMS Lee Farrell - Canon Information Systems Steve Gebert - IBM deBry, Hastings, Herriot, Isaacson, Powell [Page 100] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Babek Jahromi, Microsoft David Kellerman - Northlake Software Rick Landau - Digital Harry Lewis - IBM Pete Loya - HP Ray Lutz - Cognisys Mike MacKay, Novell, Inc. Carl-Uno Manros, Xerox, Corp. Jay Martin - Underscore Stan McConnell - Xerox Ira McDonald, High North Inc. Paul Moore, Microsoft Pat Nogay - IBM Bob Pentecost - HP Rob Rhoads - Intel David Roach - Unisys Stuart Rowley, Kyocera Hiroyuki Sato - Canon Bob Setterbo - Adobe Devon Taylor, Novell, Inc. Mike Timperman - Lexmark Randy Turner - Sharp Atsushi Yuki - Kyocera Lloyd Young - Lexmark Bill Wagner - DPI Jim Walker - DAZEL Chris Wellens - Interworking Labs Rob Whittle - Novell Don Wright - Lexmark Peter Zehler, Xerox, Corp. Steve Zilles, Adobe deBry, Hastings, Herriot, Isaacson, Powell [Page 101] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 12. APPENDIX A: Terminology This specification uses the terminology defined in this section. 12.1 Conformance Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. The sections below reiterate these definitions and include some additional ones. 12.1.1 MUST This word, or the terms "REQUIRED", "SHALL" or "MANDATORY", means that the definition is an absolute requirement of the specification. 12.1.2 MUST NOT This phrase, or the phrase "SHALL NOT", means that the definition is an absolute prohibition of the specification. 12.1.3 SHOULD This word, or the adjective "RECOMMENDED", means that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course. 12.1.4 SHOULD NOT This phrase, or the phrase "NOT RECOMMENDED" means that there may exist valid reasons in particular circumstances when the particular behavior is acceptable or even useful, but the full implications should be understood and the case carefully weighed before implementing any behavior described with this label. 12.1.5 MAY This word, or the adjective "OPTIONAL", means that an item is truly optional. One vendor may choose to include the item because a particular marketplace requires it or because the vendor feels that it enhances the product while another vendor may omit the same item. An implementation which does not include a particular option MUST be prepared to interoperate with another implementation which does include the option, though perhaps with reduced functionality. In the deBry, Hastings, Herriot, Isaacson, Powell [Page 102] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 same vein an implementation which does include a particular option MUST be prepared to interoperate with another implementation which does not include the option (except, of course, for the feature the option provides.) 12.1.6 NEED NOT The verb "NEED NOT" indicates an action that the subject of the sentence does not have to implement in order to claim conformance to the standard. The verb "NEED NOT" is used instead of "MAY NOT" since "MAY NOT" sounds like a prohibition. 12.2 Model Terminology 12.2.1 Keyword Keywords are used within this document as identifiers of semantic entities within the abstract model. Attribute names, some attribute values, attribute syntaxes, and attribute group names are represented as keywords. In this document, a keyword is a sequence of characters (length of 1 to 255) which consists of the following ASCII characters: lower-case letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"), period ("."), and underscore ("_"). A keyword starts with a lower- case letter. 12.2.2 Attributes An attribute is an item of information that is associated with an instance of an IPP object. An attribute consists of an attribute name and an attribute value(s). Each attribute has a specific syntax. All attributes are defined in section 4. Job Template Attributes described in section 4.2. The client optionally supplies Job Template attributes in a create request (operation requests that create Job objects). The Printer object has associated attributes which define supported and default values for the Printer. 12.2.2.1 Attribute Name Each attribute is uniquely identified in this document by its attribute name. An attribute name is a keyword. The keyword attribute name is given in the section header describing that attribute. In running text in this document, attribute names are indicated inside double quotation marks (") where the quotation marks are not part of the keyword itself. deBry, Hastings, Herriot, Isaacson, Powell [Page 103] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 12.2.2.2 Attribute Group Name Related attributes are grouped into named groups. The name of the group is a keyword. The group name may be used in place of naming all the attributes in the group explicitly. Attribute groups are defined in section 3. 12.2.2.3 Attribute Value Each attribute has one or more values. Attribute values are represented in the syntax type specified for that attribute. In running text in this document, attribute values are indicated inside single quotation marks ('), whether their attribute syntax is keyword, integer, text, etc. where the quotation marks are not part of the value itself. 12.2.2.4 Attribute Syntax Each attribute is defined using an explicit syntax type. In this document, each syntax type is defined as a keyword with specific meaning. The protocol specification document [IPP-PRO] indicates the actual "on-the-wire" encoding rules for each syntax type. Attribute syntax types are defined in section 4.1. 12.2.3 Supports By definition, a Printer object supports an attribute only if that Printer object responds with the corresponding attribute populated with some value(s) in a response to a query for that attribute. A Printer object supports an attribute value if the value is one of Printer object's "supported values" attributes. The device behind a Printer object may exhibit a behavior that corresponds to some IPP attribute, but if the Printer object, when queried for that attribute, doesn't respond with the attribute, then as far as IPP is concerned, that implementation does not support that feature. If the Printer object supports Job Template attribute "foo" then it supports both a "foo-default" default value attribute and a "foo-supported" supported values attribute. If the Printer object's "foo-supported" attribute is not populated with some value (even if that value is a legal value for that attribute), then that Printer object does not support that value. A conforming implementation SHALL support all MANDATORY attributes. However, even for MANDATORY attributes, conformance to IPP does not mandate that all implementations support all possible values representing all possible job processing behaviors and features. For example, if a given instance of a Printer supports only certain document formats, then that Printer responds with the "document- deBry, Hastings, Herriot, Isaacson, Powell [Page 104] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 format-supported" attribute populated with a set of values, possibly only one, taken from the entire set of possible values defined for that attribute. This limited set of values represents the Printer's set of supported document formats. Supporting an attribute and some set of values for that attribute enables IPP end users to be aware of and make use of those features associated with that attribute and those values. If an implementation chooses to not support an attribute or some specific value, then IPP end users would have no ability to make use of that feature within the context of IPP itself. However, due to existing practice and legacy systems which are not IPP aware, there might be some other mechanism outside the scope of IPP to control or request the "unsupported" feature (such as embedded instructions within the document data itself). For example, consider the "finishings-supported" attribute. If a Printer is not physically capable of stapling, the "finishings- supported" attribute MUST NOT be populated with the value of 'staple'. If a Printer is physically capable of stapling, an implementation MAY choose to support the "finishings-supported" attribute and the value of 'staple'. Doing so, would enable end users to be aware of and make use of the stapling feature. Without support for the value 'staple', an IPP end user would have no means within the protocol itself to request that a Job be stapled. However an existing document data formatter might be able to request that the document be stapled directly within the document data itself. In this case, the IPP implementation does not "support" stapling, however the end user is still able to have some control over the stapling of the completed job. Even though support for Job Template attributes by a Printer object is OPTIONAL, it is RECOMMENDED that if the device behind a Printer object is capable of realizing any feature or function that corresponds to an IPP attribute and some associated value, then that implementation support that IPP attribute and value. The set of values in any of the supported value attributes is set (populated) by some administrative process or automatic sensing mechanism that is outside the scope of IPP. For administrative policy and control reasons, an administrator may choose to make only a subset of possible values visible to the end user. In this case, the real output device behind the IPP Printer abstraction may be capable of a certain feature, however an administrator is specifying that access to that feature not flow back to the end user through the IPP protocol. Also, since a Printer object may represent a logical print device (not just a physical devices) the actual process for supporting a value is undefined and left up to the implementation. However, if a Printer object supports a value, some manual human action may be needed to realize the semantic action associated with the value, but no end user deBry, Hastings, Herriot, Isaacson, Powell [Page 105] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 action is required. For example, if one of the values in the "finishings-supported" attribute is 'staple', the actual process might be an automatic staple action by a physical device controlled by some command sent to the device. Or, the actual process of stapling might be a manual action by an operator at an operator attended Printer object. For another example of how supported attributes function, consider an system administrator that desire to control all print jobs so that no cover sheets are printed in order to conserve paper. To force no job sheets, the system administrator sets the only supported value for the "job-sheets-supported" attribute to 'none'. In this case, if a client requests anything except 'none', the create request is rejected (depending on the value of "ipp-attribute-fidelity" of course). To force the use of banner pages on all jobs, the administrator does not include the value 'none' in the "job-sheets- supported" attribute. In this case, if a client requests 'none', the create request is rejected (again depending on the value of "ipp- attribute-fidelity"). 12.2.4 print-stream page A "print-stream page" is a page according to the definition of pages in the language used to express the document data. 12.2.5 imposed page An "imposed page" is a page created by placing N print-stream pages onto a single media page. 13. APPENDIX B: Status Codes This section defines status code keywords that are used to provide semantic information on the results of an operation request. Each operation response MUST include a status code. For error type status codes, the response MAY also contain a status message that provides a short textual description of the status. The status code is intended for use by automata, and the status message is intended for the human end user. Since the status message is an OPTIONAL component of the operation response, an IPP application (i.e. a browser, GUI, print driver or gateway) is NOT REQUIRED to examine or display the status message. The prefix of the status keyword defines the class of response as follows: "informational" - Request received, continuing process "successful" - The action was successfully received, understood, and accepted deBry, Hastings, Herriot, Isaacson, Powell [Page 106] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 "redirection" - Further action must be taken in order to complete the request "client-error" - The request contains bad syntax or cannot be fulfilled "server-error" - The server failed to fulfill an apparently valid request Since IPP status codes are type2 enums, they are extensible. IPP applications are NOT REQUIRED to understand the meaning of all registered status codes, though such understanding is obviously desirable. However, applications SHALL understand the class of any status code, as indicated by the prefix, and treat any unrecognized response as being equivalent to the first status code of that class, with the exception that an unrecognized response shall not be cached. For example, if an unrecognized status code of "client-error-foo-bar" is received by the client, it can safely assume that there was something wrong with its request and treat the response as if it had received a "client-error-bad-request" status code. In such cases, IPP applications SHOULD present the OPTIONAL message (if present) to the end user since the message is likely to contain human readable information which will help to explain the unusual status. 13.1 Status Codes Each status code is described below. Section 13.2 contains a table that indicates which status codes apply to which operations. 13.1.1 Informational This class of status code indicates a provisional response and is to be used for informational purposes only. There are no status codes defined in IPP 1.0 for this class of status code. 13.1.2 Successful Status Codes This class of status code indicates that the client's request was successfully received, understood, and accepted. 13.1.2.1 successful-ok (0x0000) The request has succeeded. deBry, Hastings, Herriot, Isaacson, Powell [Page 107] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001) The request has succeeded, but since ignoring or substituting of values was requested ("ipp-attribute-fidelity" set to 'false' in the create request), some attributes were ignored or unsupported values were substituted with supported values in order to process the job without rejecting it. 13.1.3 Redirection Status Codes This class of status code indicates that further action needs to be taken to fulfill the request. There are no status codes defined in IPP 1.0 for this class of status code. 13.1.4 Client Error Status Codes This class of status code is intended for cases in which the client seems to have erred. The server SHOULD return a message containing an explanation of the error situation and whether it is a temporary or permanent condition. 13.1.4.1 client-error-bad-request (0x0400) The request could not be understood by the server due to malformed syntax. The IPP application SHOULD NOT repeat the request without modifications. 13.1.4.2 client-error-forbidden (0x0401) The server understood the request, but is refusing to fulfill it. Additional authentication information or authorization credentials will not help and the request SHOULD NOT be repeated. This status code is commonly used when the server does not wish to reveal exactly why the request has been refused or when no other response is applicable. 13.1.4.3 client-error-not-authenticated (0x0402) The request requires user authentication. The IPP client may repeat the request with suitable authentication information. If the request already included authentication information, then this status code indicates that authorization has been refused for those credentials. If this response contains the same challenge as the prior response, and the user agent has already attempted authentication at least once, then the response message may contain relevant diagnostic information. deBry, Hastings, Herriot, Isaacson, Powell [Page 108] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 This status codes reveals more information than "client-error- forbidden" and "client-error-not-authenticated". 13.1.4.4 client-error-not-authorized (0x0403) The requester is not authorized to perform the request. Additional authentication information or authorization credentials will not help and the request SHOULD NOT be repeated. This status code is used when the server wishes to reveal that the authentication information is understandable, however, the requester is explicitly not authorized to perform the request. This status codes reveals more information than "client-error-forbidden" and "client-error-not-authenticated". 13.1.4.5 client-error-not-possible (0x0404) This status code is used when the request is for something that can not happen. For example, there might be a request to cancel a job that has already been canceled or aborted by the system. The IPP client SHOULD NOT repeat the request. 13.1.4.6 client-error-timeout (0x0405) The client did not produce a request within the time that the server was prepared to wait. For example, a client issued a Create-Job operation and then, after a long period of time, issued a Send- Document operation and this error status code was returned in response to the Send-Document request. The server might have been forced to clean up resources that had been held for the waiting additional Documents. The server was forced to close the Job since the client took too long. The client SHOULD NOT repeat the request without modifications. 13.1.4.7 client-error-not-found (0x0406) The server has not found anything matching the request URI. No indication is given of whether the condition is temporary or permanent. For example, a client with an old reference to a Job (a URI) tries to cancel the Job, however in the mean time the Job might have been completed and all record of it at the Printer has been deleted. This status code, 'client-error-not-found' is returned indicating that the referenced Job can not be found. This error status code is also used when a client supplies a URI as a reference to the document data in either a Print-URI or Send-URI operation however the document can not be found. In practice, an IPP application should avoid a not found situation by first querying and presenting a list of valid Printer URIs and Job URIs to the end-user. deBry, Hastings, Herriot, Isaacson, Powell [Page 109] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.1.4.8 client-error-gone (0x0407) The requested object is no longer available at the server and no forwarding address is known. This condition should be considered permanent. Clients with link editing capabilities should delete references to the request URI after user approval. If the server does not know or has no facility to determine, whether or not the condition is permanent, the status code "client-error-not-found" should be used instead. This response is primarily intended to assist the task of web maintenance by notifying the recipient that the resource is intentionally unavailable and that the server owners desire that remote links to that resource be removed. It is not necessary to mark all permanently unavailable resources as "gone" or to keep the mark for any length of time -- that is left to the discretion of the server owner. 13.1.4.9 client-error-request-entity-too-large (0x0408) The server is refusing to process a request because the request entity is larger than the server is willing or able to process. An IPP Printer returns this status code when it limits the size of print jobs and it receives a print job that exceeds that limit or when the attributes are so many that their encoding causes the request entity to exceed server capacity. 13.1.4.10 client-error-request-URI-too-long (0x0409) The server is refusing to service the request because the request URI is longer than the server is willing to interpret. This rare condition is only likely to occur when a client has improperly submitted a request with long query information (e.g. an IPP application allows an end-user to enter an invalid URI), when the client has descended into a URI "black hole" of redirection (e.g., a redirected URI prefix that points to a suffix of itself), or when the server is under attack by a client attempting to exploit security holes present in some servers using fixed-length buffers for reading or manipulating the Request-URI. 13.1.4.11 client-error-unsupported-document-format (0x040A) The server is refusing to service the request because the document data is in a format, as specified in the "document-format" input attribute, that is not supported by the Printer object. deBry, Hastings, Herriot, Isaacson, Powell [Page 110] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.1.4.12 client-error-attribute-not-supported (0x040B) For a Create-Job, Print-Job or Validate-Job operation, if the IPP Printer does not support one or more attributes or attribute values supplied in the request, the Printer shall return this status. For example, if the request indicates 'iso-a4' media, but that media type is not supported by the Printer. Or, if the client supplies an optional attribute and the attribute itself is not even supported by the Printer. If "ipp-attribute-fidelity" is set to false, the Printer can ignore or substitute values for unsupported attributes and values rather than reject the request and return this status code. For a Get-Jobs operation, if the IPP Printer does not support one of the requested attributes, the Printer shall return this status. In practice, an IPP application should avoid this situation by querying an IPP Printer for its valid attributes and values before performing an operation on the Printer. 13.1.4.13 client-error-uri-scheme-not-supported (0x040C) The type of the client supplied URI in a Print-URI or a Send-URI operation is not supported. 13.1.4.14 client-error-charset-not-supported (0x040D) For any operation, if the IPP Printer does not support the charset supplied by the client in the "attributes-charset" operation attribute, the Printer SHALL reject the operation and return this status (see Section 3.1.3.1). 13.1.4.15 client-error-natural-language-not-supported (0x040E) For any operation, if the IPP Printer does not support the natural language supplied by the client in the "attributes-natural-language" operation attribute and the implementation has chosen to reject the operation, the Printer SHALL return this status (see Section 3.1.3.1). 13.1.5 Server Error Status Codes This class of status codes indicates cases in which the server is aware that it has erred or is incapable of performing the request. The server SHOULD include a message containing an explanation of the error situation, and whether it is a temporary or permanent condition. deBry, Hastings, Herriot, Isaacson, Powell [Page 111] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.1.5.1 server-error-internal- error (0x0500) The server encountered an unexpected condition that prevented it from fulfilling the request. This error status code differs from "server- error-temporary-error" in that it implies a more permanent type of internal error. It also differs from "server-error-device-error" in that it implies an unexpected condition (unlike a paper-jam or out-of- toner problem which is undesirable but expected). This error status code indicates that probably some knowledgeable human intervention is required. 13.1.5.2 server-error-operation-not-supported (0x0501) The server does not support the functionality required to fulfill the request. This is the appropriate response when the server does not recognize an operation or is not capable of supporting it. 13.1.5.3 server-error-service-unavailable (0x0502) The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay may be indicated in the message. If no delay is given, the IPP application should handle the response as it would for a "server-error-temporary-internal-error" response. If the condition is more permanent, the error status codes "client-error-gone" or "client-error-not-found" could be used. 13.1.5.4 server-error-version-not-supported (0x0503) The server does not support, or refuses to support, the IPP protocol version that was used in the request message. The server is indicating that it is unable or unwilling to complete the request using the same version as supplied in the request other than with this error message. The response should contain a Message describing why that version is not supported and what other versions are supported by that server. A conforming IPP client shall specify the valid version (IPP 1.0)on each request. A conforming IPP server (IPP 1.0) SHALL NOT return this status code to a conforming IPP 1.0 client. An IPP server shall return this status code to a non-conforming IPP client. 13.1.5.5 server-error-device-error (0x0504) A printer error, such as a paper jam, occurs while the IPP Printer processes a Print or Send operation. The response contains the true Job Status (the values of the "job-state" and "job-state-reasons" deBry, Hastings, Herriot, Isaacson, Powell [Page 112] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 attributes). Additional information can be returned in the optional "job-state-message" attribute value or in the OPTIONAL status message that describes the error in more detail. This error status code is only returned in situations where the Printer is unable to accept the create request because of such a device error. For example, if the Printer is unable to spool, and can only accept one job at a time, the reason it might reject a create request is that the printer currently has a paper jam. In many cases however, where the Printer object can accept the request even though the Printer has some error condition, the 'successful-ok' status code will be returned. In such a case, the client would look at the returned Job Object Attributes or later query the Printer to determine its state and state reasons. 13.1.5.6 server-error-temporary-error (0x0505) A temporary error such as a buffer full write error, a memory overflow (i.e. the document data exceeds the memory of the Printer), or a disk full condition, occurs while the IPP Printer processes an operation. The client MAY try the unmodified request again at some later point in time with an expectation that the temporary internal error condition may have been cleared. deBry, Hastings, Herriot, Isaacson, Powell [Page 113] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 13.2 Status Codes for IPP Operations PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document SU = Send-URI, V = Validate-Job, GA = Get-Attributes, GJ = Get-Jobs C = Cancel-Job IPP Operations IPP Status Keyword PJ PU CJ SD SU V GA GJ C ------------------ -- -- -- -- -- - -- -- - successful-OK x x x x x x x x x successful-ok-ignored-or-substituted- x x x x x x attributes client-error-bad-request x x x x x x x x x client-error-not-authenticated x x x x x x x x x client-error-not-authorized x x x x x x x x x client-error-forbidden x x x x x x x x x client-error-not-possible x x x x x x x x x client-error-not-found x x x x x x x x x client-error-timeout x x x x x x x x x client-error-gone x x x x x x x x x client-error-request-entity-too-large x X X X X X X X X client-error-request-URI-too-long x x x x x x x x x client-error-unsupported-document-format x x x x client-error-attribute-value-not- x x x x supported server-error-internal-error x x x x x x x x x server-error-service-unavailable x x x x x x x x x server-error-timeout x x x x x x x x x server-error-HTTP-version-not-supported x x x x x x x x x server-error-IPP-version-not-supported x x x x x x x x x server-error-device-error x x x x x server-error-temporary-error x x x x x 14. APPENDIX C: "media" keyword values Standard keyword values are taken from several sources. Standard values are defined (taken from DPA[ISODPA] and the Printer MIB[RFC1759]): 'default': The default medium for the output device 'iso-a4-white': Specifies the ISO A4 white medium 'iso-a4-colored': Specifies the ISO A4 colored medium 'iso-a4-transparent' Specifies the ISO A4 transparent medium 'iso-a3-white': Specifies the ISO A3 white medium 'iso-a3-colored': Specifies the ISO A3 colored medium 'iso-a5-white': Specifies the ISO A5 white medium deBry, Hastings, Herriot, Isaacson, Powell [Page 114] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'iso-a5-colored': Specifies the ISO A5 colored medium 'iso-b4-white': Specifies the ISO B4 white medium 'iso-b4-colored': Specifies the ISO B4 colored medium 'iso-b5-white': Specifies the ISO B5 white medium 'iso-b5-colored': Specifies the ISO B5 colored medium 'jis-b4-white': Specifies the JIS B4 white medium 'jis-b4-colored': Specifies the JIS B4 colored medium 'jis-b5-white': Specifies the JIS B5 white medium 'jis-b5-colored': Specifies the JIS B5 colored medium The following standard values are defined for North American media: 'na-letter-white': Specifies the North American letter white medium 'na-letter-colored': Specifies the North American letter colored medium 'na-letter-transparent': Specifies the North American letter transparent medium 'na-legal-white': Specifies the North American legal white medium 'na-legal-colored': Specifies the North American legal colored medium The following standard values are defined for envelopes: 'iso-b4-envelope': Specifies the ISO B4 envelope medium 'iso-b5-envelope': Specifies the ISO B5 envelope medium 'iso-c3-envelope': Specifies the ISO C3 envelope medium 'iso-c4-envelope': Specifies the ISO C4 envelope medium 'iso-c5-envelope': Specifies the ISO C5 envelope medium 'iso-c6-envelope': Specifies the ISO C6 envelope medium 'iso-designated-long-envelope': Specifies the ISO Designated Long envelope medium 'na-10x13-envelope': Specifies the North American 10x13 envelope medium 'na-9x12-envelope': Specifies the North American 9x12 envelope medium 'monarch-envelope': Specifies the Monarch envelope 'na-number-10-envelope': Specifies the North American number 10 business envelope medium 'na-7x9-envelope': Specifies the North American 7x9 inch envelope 'na-9x11-envelope': Specifies the North American 9x11 inch envelope 'na-10x14-envelope': Specifies the North American 10x14 inch envelope 'na-number-9-envelope': Specifies the North American number 9 business envelope 'na-6x9-envelope': Specifies the North American 6x9 inch envelope deBry, Hastings, Herriot, Isaacson, Powell [Page 115] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'na-10x15-envelope': Specifies the North American 10x15 inch envelope The following standard values are defined for the less commonly used media (white-only): 'executive-white': Specifies the white executive medium 'folio-white': Specifies the folio white medium 'invoice-white': Specifies the white invoice medium 'ledger-white': Specifies the white ledger medium 'quarto-white': Specified the white quarto medium 'iso-a0-white': Specifies the ISO A0 white medium 'iso-a1-white': Specifies the ISO A1 white medium 'iso-a2-white': Specifies the ISO A2 white medium 'iso-a6-white': Specifies the ISO A6 white medium 'iso-a7-white': Specifies the ISO A7 white medium 'iso-a8-white': Specifies the ISO A8 white medium 'iso-a9-white': Specifies the ISO A9 white medium 'iso-10-white': Specifies the ISO A10 white medium 'iso-b0-white': Specifies the ISO B0 white medium 'iso-b1-white': Specifies the ISO B1 white medium 'iso-b2-white': Specifies the ISO B2 white medium 'iso-b3-white': Specifies the ISO B3 white medium 'iso-b6-white': Specifies the ISO B6 white medium 'iso-b7-white': Specifies the ISO B7 white medium 'iso-b8-white': Specifies the ISO B8 white medium 'iso-b9-white': Specifies the ISO B9 white medium 'iso-b10-white': Specifies the ISO B10 white medium 'jis-b0-white': Specifies the JIS B0 white medium 'jis-b1-white': Specifies the JIS B1 white medium 'jis-b2-white': Specifies the JIS B2 white medium 'jis-b3-white': Specifies the JIS B3 white medium 'jis-b6-white': Specifies the JIS B6 white medium 'jis-b7-white': Specifies the JIS B7 white medium 'jis-b8-white': Specifies the JIS B8 white medium 'jis-b9-white': Specifies the JIS B9 white medium 'jis-b10-white': Specifies the JIS B10 white medium The following standard values are defined for engineering media: 'a': Specifies the engineering A size medium 'b': Specifies the engineering B size medium 'c': Specifies the engineering C size medium 'd': Specifies the engineering D size medium 'e': Specifies the engineering E size medium deBry, Hastings, Herriot, Isaacson, Powell [Page 116] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 The following standard values are defined for input-trays (from ISO DPA and the Printer MIB): 'top': The top input tray in the printer. 'middle': The middle input tray in the printer. 'bottom': The bottom input tray in the printer. 'envelope': The envelope input tray in the printer. 'manual': The manual feed input tray in the printer. 'large-capacity': The large capacity input tray in the printer. 'main': The main input tray 'side': The side input tray The following standard values are defined for media sizes (from ISO DPA): 'iso-a0': Specifies the ISO A0 size: 841 mm by 1189 mm as defined in ISO 216 'iso-a1': Specifies the ISO A1 size: 594 mm by 841 mm as defined in ISO 216 'iso-a2': Specifies the ISO A2 size: 420 mm by 594 mm as defined in ISO 216 'iso-a3': Specifies the ISO A3 size: 297 mm by 420 mm as defined in ISO 216 'iso-a4': Specifies the ISO A4 size: 210 mm by 297 mm as defined in ISO 216 'iso-a5': Specifies the ISO A5 size: 148 mm by 210 mm as defined in ISO 216 'iso-a6': Specifies the ISO A6 size: 105 mm by 148 mm as defined in ISO 216 'iso-a7': Specifies the ISO A7 size: 74 mm by 105 mm as defined in ISO 216 'iso-a8': Specifies the ISO A8 size: 52 mm by 74 mm as defined in ISO 216 'iso-a9': Specifies the ISO A9 size: 37 mm by 52 mm as defined in ISO 216 'iso-a10': Specifies the ISO A10 size: 26 mm by 37 mm as defined in ISO 216 'iso-b0': Specifies the ISO B0 size: 1000 mm by 1414 mm as defined in ISO 216 'iso-b1': Specifies the ISO B1 size: 707 mm by 1000 mm as defined in ISO 216 'iso-b2': Specifies the ISO B2 size: 500 mm by 707 mm as defined in ISO 216 'iso-b3': Specifies the ISO B3 size: 353 mm by 500 mm as defined in ISO 216 'iso-b4': Specifies the ISO B4 size: 250 mm by 353 mm as defined in ISO 216 deBry, Hastings, Herriot, Isaacson, Powell [Page 117] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'iso-b5': Specifies the ISO B5 size: 176 mm by 250 mm as defined in ISO 216 'iso-b6': Specifies the ISO B6 size: 125 mm by 176 mm as defined in ISO 216 'iso-b7': Specifies the ISO B7 size: 88 mm by 125 mm as defined in ISO 216 'iso-b8': Specifies the ISO B8 size: 62 mm by 88 mm as defined in ISO 216 'iso-b9': Specifies the ISO B9 size: 44 mm by 62 mm as defined in ISO 216 'iso-b10': Specifies the ISO B10 size: 31 mm by 44 mm as defined in ISO 216 'na-letter': Specifies the North American letter size: 8.5 inches by 11 inches 'na-legal': Specifies the North American legal size: 8.5 inches by 14 inches 'executive': Specifies the executive size (7.25 X 10.5 in) 'folio': Specifies the folio size (8.5 X 13 in) 'invoice': Specifies the invoice size (5.5 X 8.5 in) 'ledger': Specifies the ledger size (11 X 17 in) 'quarto': Specifies the quarto size (8.5 X 10.83 in) 'iso-c3': Specifies the ISO C3 size: 324 mm by 458 mm as defined in ISO 269 'iso-c4': Specifies the ISO C4 size: 229 mm by 324 mm as defined in ISO 269 'iso-c5': Specifies the ISO C5 size: 162 mm by 229 mm as defined in ISO 269 'iso-c6': Specifies the ISO C6 size: 114 mm by 162 mm as defined in ISO 269 'iso-designated-long': Specifies the ISO Designated Long size: 110 mm by 220 mm as defined in ISO 269 'na-10x13-envelope': Specifies the North American 10x13 size: 10 inches by 13 inches 'na-9x12-envelope': Specifies the North American 9x12 size: 9 inches by 12 inches 'na-number-10-envelope': Specifies the North American number 10 business envelope size: 4.125 inches by 9.5 inches 'na-7x9-envelope': Specifies the North American 7x9 inch envelope size 'na-9x11-envelope': Specifies the North American 9x11 inch envelope size 'na-10x14-envelope': Specifies the North American 10x14 inch envelope size 'na-number-9-envelope': Specifies the North American number 9 business envelope size 'na-6x9-envelope': Specifies the North American 6x9 envelope size 'na-10x15-envelope': Specifies the North American 10x15 envelope size deBry, Hastings, Herriot, Isaacson, Powell [Page 118] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 'monarch-envelope': Specifies the Monarch envelope size (3.87 x 7.5 in) 'jis-b0': Specifies the JIS B0 size: 1030mm x 1456mm 'jis-b1': Specifies the JIS B1 size: 728mm x 1030mm 'jis-b2': Specifies the JIS B2 size: 515mm x 728mm 'jis-b3': Specifies the JIS B3 size: 364mm x 515mm 'jis-b4': Specifies the JIS B4 size: 257mm x 364mm 'jis-b5': Specifies the JIS B5 size: 182mm x 257mm 'jis-b6': Specifies the JIS B6 size: 128mm x 182mm 'jis-b7': Specifies the JIS B7 size: 91mm x 128mm 'jis-b8': Specifies the JIS B8 size: 64mm x 91mm 'jis-b9': Specifies the JIS B9 size: 45mm x 64mm 'jis-b10': Specifies the JIS B10 size: 32mm x 45mm 15. APPENDIX D: Processing IPP Attributes When submitting a print job to a Printer object, the IPP model allows a client to supply operation and Job Template attributes along with the document data. These Job Template attributes in the create request affect the rendering, production and finishing of the documents in the job. Similar types of instructions may also be contained in the document to be printed, that is, embedded within the print data itself. In addition, the Printer has a set of attributes that describe what rendering and finishing options which are supported by that Printer. This model, which allows for flexibility and power, also introduces the potential that at job submission time, these client-supplied attributes may conflict with either: - what the implementation is capable of realizing (i.e., what the Printer supports), as well as - the instructions embedded within the print data itself. The following sections describe how these two types of conflicts are handled in the IPP model. 15.1 Fidelity If there is a conflict between what the client requests and what a Printer supports, the client may request one of two possible conflict handling mechanisms: 1) either reject the job since the job can not be processed exactly as specified, or 2) allow the Printer to make any changes necessary to proceed with processing the Job the best it can. deBry, Hastings, Herriot, Isaacson, Powell [Page 119] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 In the first case the client is indicating to the Printer: "Print the job exactly as specified with no exceptions, and if that can't be done, don't even bother printing the job at all." In the second case, the client is indicating to the Printer: "It is more important to make sure the job is printed rather than be processed exactly as specified; just make sure the job is printed even if client supplied attributes need to be changed or ignored." The IPP model accounts for this situation by introducing an "ipp- attribute-fidelity" attribute. In a create request, "ipp-attribute-fidelity" is a boolean attribute that is OPTIONALLY supplied by the client. The value 'true' indicates that total fidelity to client supplied attributes and values is required. The client is requesting that the Job be printed exactly as specified, and if that is not possible then the job must be rejected rather than processed incorrectly. The value 'false' indicates that a reasonable attempt to print the Job is acceptable. If a Printer does not support some of the client supplied Job Template attributes or values, the Printer may ignore them or substitute any supported value for unsupported values. The Printer may choose to substitute the default value associated with that attribute, or use some other supported value that is similar to the unsupported requested value. For example, if a client supplies a "media" value of 'na-letter', the Printer may choose to substitute 'iso-a4' rather than a default value of 'envelope'. Since this is an OPTIONAL attribute, if the client does not supply a value, the Printer assumes a value of 'false'. Each Printer implementation MUST support both types of "fidelity" printing (that is whether the client supplies a value of 'true' or 'false'). This is possible across all types of implementations, since there is a broad range of acceptable actions when substituting or ignoring unsupported attributes and values. Also, even if the client supplies a value of 'false', a Printer might still reject the Job for any reason including an unsupported attributes and/or values. In the other case, where the client requests a value of 'true', it is expected that the Printer support this type of printing since the Printer is already indicating functional support corresponding to all advertised supported attributes and values. Since a client can always query a Printer to find out exactly what is and is not supported, "ipp-attribute-fidelity" set to 'false' is useful when: 1) The End-User uses a command line interface to request attributes that might not be supported. deBry, Hastings, Herriot, Isaacson, Powell [Page 120] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 2) In a GUI context, if the End User expects the job might be moved to another printer and prefers a sub-optimal result to nothing at all. 3) The End User just wants something reasonable in lieu of nothing at all. 15.2 Page Description Language (PDL) Override If there is a conflict between the value of an IPP Job Template attribute and a corresponding instruction in the document data, the value of the IPP attribute SHOULD take precedence over the document instruction. Consider the case where a previously formatted file of document data is sent to an IPP Printer. In this case, if the client supplies any attributes at job submission time, the client desires that those attributes override the embedded instructions. Consider the case were a previously formatted document has embedded in it commands to load 'iso-a4' media. However, the document is passed to an end user that only has access to a printer with 'na-letter' media loaded. That end user most likely wants to submit that document to an that IPP Printer with the "media" Job Template attribute set to 'na- letter'. The job submission attribute should take precedence over the embedded PDL instruction. However, until companies that supply document data interpreters allow a way for external IPP attributes to take precedence over embedded job production instructions, a Printer might not be able to support the semantics that IPP attributes override the embedded instructions. The IPP model accounts for this situation by introducing a "pdl- override-supported" attribute. This MANDATORY attribute takes on the following values: - 'attempted': This value indicates that the Printer attempts to make sure that IPP attribute values take precedence over embedded instructions in the document data, however there is no guarantee. - 'not-attempted': This value indicates that the Printer makes not attempt to ensure that IPP attribute values take precedence over embedded instructions in the document data. At job processing time, an implementation that supports the value of 'attempted' might try to do one of several different actions: 1) generate an output device specific command sequence to realize the feature represented by the IPP attribute value 2) parse the document data itself and replace the conflicting embedded instruction with a new embedded instruction that matches the intent of the IPP attribute value deBry, Hastings, Herriot, Isaacson, Powell [Page 121] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 3) indicate to the Printer that external supplied attributes take precedence over embedded instructions and then pass the external IPP attribute values to the document data interpreter 4) anything else that allows for the semantics that IPP attributes override embedded document data instructions. Since 'attempted' does not offer any type of guarantee, even though a given implementation might not do a very "good" job of attempting to ensure that IPP attributes take a higher precedence over instructions embedded in the document data, it would still be a conforming implementation. Note: The "ipp-attribute-fidelity" attribute applies to the Printer's ability to either accept or reject other unsupported attributes. In other words, if "ipp-attribute-fidelity" is set to 'true', a Job is accepted if and only if the client supplied attributes and values are supported by the Printer. Whether these attributes actually affect the processing of the Job depends on the ability of the Printer to override the instructions embedded in the document data with the semantics of the IPP attributes. If the document data attributes can be overridden ("pdl-override-supported" set to 'attempted'), the Printer makes an attempt to use the IPP attributes when processing the Job. If the document data attributes can not be overridden ("pdl- override-supported" set to 'not-attempted'), the Printer makes no attempt to use the IPP attributes when processing the Job, and hence, the IPP attributes may fail to affect the Job processing and output in any manner whatsoever. 15.3 Suggested Operation Processing Algorithm When a Printer receives a create request, the Printer either accepts or rejects the request. The Printer accepts the create request and creates a Job object if it is able to accept all Job Template and Document attributes in the request. The Printer rejects the request and does not create a Job object if the Printer rejects any Job Template or Document attribute in the request. In order to determine whether or not to accept or reject the request, the Printer SHOULD use the following algorithm: 1. The implementation checks to see if the operation is supported. If not, the Printer rejects the request and sets the appropriate status code in the response. 2. The implementation checks to see if the requested major version number is supported. If not, the Printer rejects the request and sets the appropriate status code in the response. Differences in the minor version number requested versus what is supported is OK deBry, Hastings, Herriot, Isaacson, Powell [Page 122] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 if a.) the requested version number has the same Major version number and the minor version number is higher than supported by the Printer object, and b.) any attributes that are not known to the recipient of the operation can be ignored (i.e., if the "ipp- attribute-fidelity" attribute has the value 'false'.) 3. The implementation checks to see if the client supplied an "ipp- attribute-fidelity" attribute. If the attribute is missing (not supplied by the client), the Printer assumes that the value is 'false'. 4. The Printer loops through all other attributes, checking to see if the requested values are supported (e.g., the value of "foo" in the request is one of the values in the Printer's "foo- supported" attribute). If the attribute or its value is unsupported, the Printer flags it as unsupported. 5. Once all attributes have been checked individually, the Printer checks for any inconsistent values among all the supported values. For example a Printer might be able to staple and to print on transparencies, however due to physical stapling limitations, the Printer might not be able to staple transparencies. Any inconsistent values are flagged as unsupported. 6. Once all attributes have been checked and validated, if "ipp- attribute-fidelity" is set to true and there are any attributes flagged as unsupported, the Printer rejects the request and returns all unsupported attributes and values in the response and sets the appropriate status code. 7. If "ipp-attribute-fidelity" is set to 'false' (or it was not supplied by the client) and there are any attributes that are flagged as unsupported, the Printer, chooses to either ignore the unsupported attributes or change the requested value to some supported value. If, for some reason, it is not possible for the implementation to ignore or substitute values and is unable to "just print the job", the Printer is still able to reject the request and return all unsupported attributes and values in the response. In doing so, the Printer sets the appropriate status code. 8a. If the requested operation is the Validate-Job operation and a "document-uri" attribute is supplied in the request, then the "document-uri" is validated as specified in section 3.2.3, Validate-Job Operation. If the Printer is able to accept the request and the validation of any "document-uri" succeeded, then the Printer object returns the status code "successful-ok". deBry, Hastings, Herriot, Isaacson, Powell [Page 123] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 Otherwise, it returns a set of unsupported attributes and/or the appropriate error status code. In either case the processing of the operation is completed and no objects are created. 8b. The operation is a create request. If the Printer is able to accept the create request (either as is or the "ipp-attribute- fidelity" attribute is set to 'false' and some of the requested attributes can be ignored or have their values substituted), then the Printer creates a new Job object . The Job object is populated with those Job Template attributes from the create request that the Printer object can honor. If the "ipp-attribute- fidelity" attribute is set to 'true', the Job Template attributes associated with the new Job object are necessarily all the Job Template attributes in the accepted create request. If the "ipp- attribute-fidelity" attribute is set to 'false', the Job Template attributes associated with the new Job object are all the client supplied Job Template attributes that are not ignored and/or have no value substitution. Thus, some of the requested Job Template attributes may not appear in the Job object because the IPP processor was not able to honor those attributes. The attributes that were honored are persistently stored with the Job object for that Job. A Get-Attributes operation on that Job object will return only those attributes that a persistently stored with the Job object. Note: All Job Template attributes that are persistently stored with the Job object are intended to be "override values"; that is, they that take precedence over whatever other embedded instructions might be in the document data itself. However, it is not possible for all implementations to realize the semantics of "override". End users may query the Printer's "pdl-override" attribute to determine if the Printer either attempts or does not attempt to override document data instructions with IPP attributes. 9. There are some cases, where a Printer supports a Job Template attribute and has an associated default value set for that attribute. In the case where a client does not supply the corresponding attribute, the Printer does not use its default values to populate Job attributes when creating the new Job object; only Job Template attributes actually in the create request are used to populate the Job object. The Printer's default values are only used at Job processing time if no other IPP attribute or instruction embedded in the document data is present. Note: If the default values associated with un-requested Job Template attributes were used to populate the Job object, then deBry, Hastings, Herriot, Isaacson, Powell [Page 124] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 these values would become "override values" rather than defaults. If the Printer supports the 'attempted' value of the "pdl- override" attribute, then these override values could replace values specified within the document data. This is not the intent of the default value mechanism. A default value for an attrbute SHALL be used only if the create request did not specify that attribute (or it was ignored when allowed by "ipp-attribute- fidelity" being 'false') and no value was provided within the content of the document data. 10. If the client does not supply a value for some Job Template attribute, and the Printer does not support that attribute, as far as IPP is concerned, the result of processing that Job (with respect to the missing attribute) is undefined. 11. Once the Job object has been created, the Printer responds back to the client with a successful response including Job status attributes that indicate the initial state of the Job ('pending', 'processing', etc.). The Printer uses its own configuration and implementation specific algorithms for scheduling the Job in the correct processing order. Once the Printer begins processing the Job, the Printer changes the Job's state to 'processing'. If the Printer supports PDL override (the "pdl-override" attribute set to 'attempted'), the implementation does its best to see that IPP attributes take precedence over embedded instructions in the document data. 12. The implementation of the Printer object continues to process the Job until it can move the Job into the 'completed' state. If an Cancel-Job operation is received, the implementation eventually moves the Job into the 'cancelled' state. If the system encounters errors during processing that do not allow it to progress the Job into a completed state, the implementation halts all processing, cleans up any resources, and moves the Job into the 'aborted' state. 13. Once the Job moves to the 'completed', 'aborted', or 'canceled' state, it is an implementation decision as to when to destroy the Job object and release all associated resources. Once the Job has been destroyed, the Printer would return either the "not- found" or "gone" status codes for operations directed at that Job. Some Printer implementations may support "ipp-attribute-fidelity" set to 'true' and "pdl-override" set to 'attempted' and yet still not be able to realize exactly what the client specifies in the create request. This is due to legacy decisions and assumptions that have been made about the role of job instructions embedded within the deBry, Hastings, Herriot, Isaacson, Powell [Page 125] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 document data and external job instructions that accompany the document data and how to handle conflicts between such instructions. The inability to be 100% precise about how a given implementation will behave is also compounded by the fact that the two special attributes, "ipp-attribute-fidelity" and "pdl-override", apply to the whole job rather than specific values for each attribute. For example, some implementations may be able to override almost all Job Template attributes except for "number-up". 15.4 Using Job Template Attributes During Document Processing. The Printer object uses some of the Job object's Job Template attributes during the processing of the document data associated with that job. These include, but are not limited to, "orientation", "number-up", "sides", "media", and "copies". The processing of each document in a Job Object SHALL follow the algorithm below. This algorithm is intended only to identify when and how attributes are to be used in processing document data and any algorithm that accomplishes the same effect can be used to implement this specification. 1. Using the "document-format" attribute or some form of format detection algorithm (if the value of "document-format" is not specific enough), determine whether or not the document data has already been formatted for printing. If the document data has been formatted, then goto step 2. Otherwise, the document data SHALL be formatted. The formatting algorithm is implementation defined and is not specified by this specification. The formatting of the document data uses the "orientation" attribute to determine how the formatted print data is place on a print- stream page, see section 4.2.15 for the details. 2. The document data is in the form of a print-stream in a known media type. The "page-range" attribute is used to select, as specified in section 4.2.14, a sub-sequence of the pages in the print-stream that are to be processed and images. 3. The input to this step is sequence of print-stream pages. This step is controlled by the "number-up" attribute. If value of "number-up" is N, then during the processing of the print-stream pages, each N print-stream pages are positioned, as specified in section 4.2.8, to create a single imposed page. If a given Document Object does not have N more print-stream pages, then the completion of the imposed page is controlled by the "multiple- document-handling" attribute as described in section 4.2.6; when the value of this attribute is 'separate-documents-collated- deBry, Hastings, Herriot, Isaacson, Powell [Page 126] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 copies', the document data from subsequent Document Objects is used to complete the imposed page. The size(scaling), position(translation) and rotation of the print- stream pages on the imposed page is implementation defined. Note that during this process the print-stream pages may be rendered to a form suitable for placing on the imposed page; this rendering is controlled by the values of the "printer-resolution" and "print-quality" attributes as described in sections 4.2.10 and 4.2.11. In the case N=1, the imposed pages are nearly the same as the print-stream pages; the differences would only be in the size, position and rotation of the print-stream page and/or any decoration, such as a frame to the page, that is added by the implementation. 4. The collection of imposed pages is placed, in sequence, onto sides of the print media. This placement is controlled by the "sides" attribute and the orientation of the page, as described in section 4.2.9. The orientation of the page is defined by the orientation of the imposed pages; for example, if "number-up" equals 2, then, typically, two portrait print-stream pages become one landscape imposed page. Note that the placement of imposed pages onto media instances is also controlled by the "multiple- document-handling" attribute as described in section 4.2.6. 5. The "copies" and "multiple-document-handling" attributes are used to determine how many copies of each media instance are created and in what order. See sections 4.2.6 and 4.2.13 for the details. 6. When the correct number of copies are created, the media instances are finished according to the values of the "finishings" attribute as described in 4.2.12. Note that sometimes finishing operations may require manual intervention to perform the finishing operations on the copies, especially uncollated copies. This specification allows any or all of the processing steps to be performed automatically or manually at the discretion of the Printer object. 16. APPENDIX E: Generic Directory Schema This section defines a generic schema for an entry in a directory service. A directory service is a means by which service users can locate service providers. In IPP environments, this means that IPP Printers can be registered (either automatically or with the help of an administrator) as entries of type printer in the directory. IPP clients can search or browse for entries of type printer. Clients use the directory service to find entries based on naming, organizational deBry, Hastings, Herriot, Isaacson, Powell [Page 127] Expires April 14, 1998 INTERNET-DRAFT IPP/1.0: Model and Semantics October 14, 1997 contexts, or filtered searches on attribute values of entries. For example, a client can find all printers in the "Local Department" context. Authentication and authorization are also often part of a directory service so that an administrator can place limits on end users so that they are only allowed to find entries to which they have certain access rights. IPP itself does not require any specific directory service protocol or provider. The generic schema is a subset of IPP Printer attributes (section 4.4). These attributes are identified as either MANDATORY or OPTIONAL for the entry itself. This conformance labeling is NOT the same conformance labeling applied to the attributes of IPP Printers themselves. MANDATORY attributes MUST be associated with each directory entry. OPTIONAL attributes SHOULD be associated with the directory entry (if known or supported). In addition, all directory entry attributes SHOULD reflect the current attribute values for the corresponding Printer object. In order to bridge between the directory service protocol and IPP, one of the MANDATORY attributes is the "printer-uri" attribute. The IPP client addresses an IPP Printer using its URI and so the directory entry's "printer-uri" becomes the link between the directory entry and the corresponding IPP Printer. The following attributes define the generic schema for directory entries of type printer: printer-uri MANDATORY Section 4.4.1 printer-tls-uri OPTIONAL Section printer-name OPTIONAL Section 4.4.2 printer-location OPTIONAL Section 4.4.3 printer-info OPTIONAL Section 4.4.4 printer-more-info OPTIONAL Section 4.4.5 printer-make-and-model OPTIONAL Section 4.4.7 security-mechanisms-supported MANDATORY Section 4.4.23 media-supported OPTIONAL Section 4.2.5 number-up-supported OPTIONAL Section 4.2.6 sides-supported OPTIONAL Section 4.2.7 printer-resolution-supported OPTIONAL Section 4.2.8 print-quality-supported OPTIONAL Section 4.2.9 color-supported OPTIONAL Section 4.4.20 finishings-supported OPTIONAL Section 4.2.10 document-formats-supported OPTAIONL Section 4.2.14 deBry, Hastings, Herriot, Isaacson, Powell [Page 128] Expires April 14, 1998