RFC - 2569

Mapping between LPD and IPP Protocols

Original:	ftp://ftp.isi.edu/in-notes/rfc2569.txt
Authors:	R. Herriot [Xerox Corporation], N. Jacobs [Sun Microsystems, Inc.], T. Hastings [Xerox Corporation], J. Martin [Underscore, Inc.]
Date:	April 1999
Category:	Experimental Standard

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Referred by:	28 RFC
Refers to:	8 RFC

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Status

This memo defines an Experimental Protocol for the Internet community. It does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1999). All Rights Reserved.

IESG Note

This document defines an Experimental protocol for the Internet community. The IESG expects that a revised version of this protocol will be published as Proposed Standard protocol. The Proposed Standard, when published, is expected to change from the protocol defined in this memo. In particular, it is expected that the standards-track version of the protocol will incorporate strong authentication and privacy features, and that an "ipp:" URL type will be defined which supports those security measures. Other changes to the protocol are also possible. Implementors are warned that future versions of this protocol may not interoperate with the version of IPP defined in this document, or if they do interoperate, that some protocol features may not be available.

The IESG encourages experimentation with this protocol, especially in combination with Transport Layer Security (TLS) [RFC 2246^prop(-> 4346^prop)], to help determine how TLS may effectively be used as a security layer for IPP.

Abstract

This document is one of a set of documents, which together describe all aspects of a new Internet Printing Protocol (IPP). IPP is an application level protocol that can be used for distributed printing using Internet tools and technologies. This document gives some advice to implementers of gateways between IPP and LPD (Line Printer Daemon). This document describes the mapping between (1) the commands and operands of the 'Line Printer Daemon (LPD) Protocol' specified in RFC 1179 and (2) the operations, operation attributes and job template attributes of the Internet Printing Protocol/1.0 (IPP). One of the purposes of this document is to compare the functionality of the two protocols. Another purpose is to facilitate implementation of gateways between LPD and IPP.

WARNING: RFC 1179 was not on the IETF standards track. While RFC 1179 was intended to record existing practice, it fell short in some areas. However, this specification maps between (1) the actual current practice of RFC 1179 and (2) IPP. This document does not attempt to map the numerous divergent extensions to the LPD protocol that have been made by many implementers.

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 [RFC2566]
      Internet Printing Protocol/1.0: Encoding and Transport [RFC2565(-> 2910prop)]
      Internet Printing Protocol/1.0: Implementors Guide [ipp-iig]
      Mapping between LPD and IPP Protocols (this document)

The document, "Design Goals 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. It calls out a subset of end user requirements that are satisfied in IPP/1.0. Operator and administrator requirements are out of scope for version 1.0.

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

The document, "Internet Printing Protocol/1.0: Model and Semantics", describes a simplified model with abstract objects, their attributes, and their operations. It introduces a Printer and a Job object. The Job object supports multiple documents per Job. It also addresses security, internationalization, and directory issues.

The document, "Internet Printing Protocol/1.0: Encoding and Transport", is a formal mapping of the abstract operations and attributes defined in the model document onto HTTP/1.1. It defines the encoding rules for a new Internet media type called ' application/ipp'.

This document "Internet Printing Protocol/1.0: Implementer's Guide", gives advice to implementers of IPP clients and IPP objects.

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