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RObust Header Compression (ROHC): A Link-Layer Assisted Profile for IP/UDP/RTP (RFC3242)

IP.com Disclosure Number: IPCOM000007881D
Original Publication Date: 2002-Apr-01
Included in the Prior Art Database: 2002-May-02
Document File: 22 page(s) / 49K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

L-E. Jonsson: AUTHOR [+2]

Abstract

This document defines a ROHC (Robust Header Compression) profile for compression of IP/UDP/RTP (Internet Protocol/User Datagram Protocol/Real-Time Transport Protocol) packets, utilizing functionality provided by the lower layers to increase compression efficiency by completely eliminating the header for most packets during optimal operation. The profile is built as an extension to the ROHC RTP profile. It defines additional mechanisms needed in ROHC, states requirements on the assisting layer to guarantee transparency, and specifies general logic for compression and decompression making use of this header-free packet.

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This is the abbreviated version, containing approximately 7% of the total text.

Network Working Group                                       L-E. Jonsson

Request for Comments: 3242                                  G. Pelletier

Category: Standards Track                                       Ericsson

                                                              April 2002

                   RObust Header Compression (ROHC):

              A Link-Layer Assisted Profile for IP/UDP/RTP

Status of this Memo

   This document specifies an Internet standards track protocol for the

   Internet community, and requests discussion and suggestions for

   improvements.  Please refer to the current edition of the "Internet

   Official Protocol Standards" (STD 1) for the standardization state

   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines a ROHC (Robust Header Compression) profile for

   compression of IP/UDP/RTP (Internet Protocol/User Datagram

   Protocol/Real-Time Transport Protocol) packets, utilizing

   functionality provided by the lower layers to increase compression

   efficiency by completely eliminating the header for most packets

   during optimal operation.  The profile is built as an extension to

   the ROHC RTP profile.  It defines additional mechanisms needed in

   ROHC, states requirements on the assisting layer to guarantee

   transparency, and specifies general logic for compression and

   decompression making use of this header-free packet.

Table of Contents

   1.  Introduction....................................................2

   2.  Terminology.....................................................4

   3.  Overview of the Link-Layer Assisted Profile.....................5

        3.1.  Providing Packet Type Identification.....................6

        3.2.  Replacing the Sequence Number............................6

        3.3.  CRC Replacement..........................................7

        3.4.  Applicability of This Profile............................7

   4.  Additions and Exceptions Compared to ROHC RTP...................8

        4.1.  Additional Packet Types..................................8

               4.1.1.  No-Header Packet (NHP)..........................8

               4.1.2.  Context Synchronization Packet (CSP)............8

               4.1.3.  Context Check Packet (CCP)......................9

Jonsson, et. al             Standards Track                     [Page 1]

RFC 3242             A Link-Layer Assisted ROHC RTP           April 2002

        4.2.  Interfaces Towards the Assisting Layer..................11

               4.2.1.  Interface, Compressor to Assisting Layer.......11

               4.2.2.  Interface, Assisting Layer to Decompressor.....12

        4.3.  Optimistic Approach Agreement...........................13

        4.4.  Fast Context Initialization, IR Redefinition............13

        4.5.  Feedback Option, CV-REQUEST.............................14

        4.6.  Periodic Context Verification...........................15

        4.7.  Use of Context Identifier...............................15

   5.  Implementation Issues..........................................15

        5.1.  Implementation Parameters and Signals...................15

               5.1.1.  Implementation Parameters at the Compressor....16

               5.1.2.  Implementation Parameters at the Decompressor..17

        5.2.  Implementation over Various Link Technologies...........18

   6.  IANA Considerations...................