15.2  Page Description Language (PDL) Override                      161
 15.3  Using Job Template Attributes During Document Processing.     163
16.APPENDIX E: Generic Directory Schema                              166
17.APPENDIX F: Change History for the Model and Semantics document   168
18.FULL COPYRIGHT STATEMENT                                          173

1. Introduction

   The Internet Printing Protocol (IPP) is an application level protocol
   that can be used for distributed printing using Internet tools and
   technologies.  IPP version 1.0 (IPP/1.0) focuses only on end user
   functionality.  This document is just one of a suite of documents
   that fully define IPP.  The full set of IPP documents includes:

     Design Goals for an Internet Printing Protocol [RFC2567]
     Rationale for the Structure and Model and Protocol for the Internet
        Printing Protocol [RFC2568]
     Internet Printing Protocol/1.0: Model and Semantics (this document)
     Internet Printing Protocol/1.0: Encoding and Transport [RFC2565]
     Internet Printing Protocol/1.0: Implementer's Guide [ipp-iig]
     Mapping between LPD and IPP Protocols [RFC2569]

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

   This document is laid out as follows:

     - The rest of Section 1 is an introduction to the IPP simplified
       model for distributed printing.
     - Section 2 introduces the object types covered in the model with
       their basic behaviors, attributes, and interactions.
     - Section 3 defines the operations included in IPP/1.0.  IPP
       operations are synchronous, therefore, for each operation, there
       is a both request and a response.
     - Section 4 defines the attributes (and their syntaxes) that are
       used in the model.
     - Sections 5 - 6 summarizes the implementation conformance
       requirements for objects that support the protocol and IANA
       considerations, respectively.
     - Sections 7 - 11 cover the Internationalization and Security
       considerations as well as References, Author contact information,
       and Formats for Registration Proposals.
     - Sections 12 - 14 are appendices that cover Terminology, Status
       Codes and Messages, and "media" keyword values.






 
RFC 2566              IPP/1.0: Model and Semantics            April 1999


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

     - Section 15 is an appendix that helps to clarify the effects of
       interactions between related attributes and their values.
     - Section 16 is an appendix that enumerates the subset of Printer
       attributes that form a generic directory schema.  These
       attributes are useful when registering a Printer so that a
       client can find the Printer not just by name, but by filtered
       searches as well.
     - Section 17 is an appendix that provides a Change History
       summarizing the clarification and changes that might affect an
       implementation since the June 30, 1998 draft.

1.1 Simplified Printing Model

   In order to achieve its goal of realizing a workable printing
   protocol for the Internet, the Internet Printing Protocol (IPP) is
   based on a simplified printing model that abstracts the many
   components of real world printing solutions.  The Internet is a
   distributed computing environment where requesters of print services
   (clients, applications, printer drivers, etc.) cooperate and interact
   with print service providers.  This model and semantics document
   describes a simple, abstract model for IPP even though the underlying
   configurations may be complex "n-tier" client/server systems.  An
   important simplifying step in the IPP model is to expose only the key
   objects and interfaces required for printing.  The model described in
   this model document does not include features, interfaces, and
   relationships that are beyond the scope of the first version of IPP
   (IPP/1.0).  IPP/1.0 incorporates many of the relevant ideas and
   lessons learned from other specification and development efforts
   [HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP].  IPP is
   heavily influenced by the printing model introduced in the Document
   Printing Application (DPA) [ISO10175] standard.  Although DPA
   specifies both end user and administrative features, IPP version 1.0
   (IPP/1.0) focuses only on end user functionality.

   The IPP/1.0 model encapsulates the important components of
   distributed printing into two object types: