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Robust Header Compression (ROHC) over PPP (RFC3241)

IP.com Disclosure Number: IPCOM000007953D
Original Publication Date: 2002-Apr-01
Included in the Prior Art Database: 2002-May-08
Document File: 13 page(s) / 25K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Bormann: AUTHOR

Abstract

This document describes an option for negotiating the use of robust header compression (ROHC) on IP datagrams transmitted over the Point-to-Point Protocol (PPP). It defines extensions to the PPP Control Protocols for IPv4 and IPv6.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 14% of the total text.

Network Working Group                                         C. Bormann

Request for Comments: 3241                                TZI/Uni Bremen

Updates: 1332                                                 April 2002

Category: Standards Track

               Robust Header Compression (ROHC) over PPP

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 describes an option for negotiating the use of robust

   header compression (ROHC) on IP datagrams transmitted over the

   Point-to-Point Protocol (PPP).  It defines extensions to the PPP

   Control Protocols for IPv4 and IPv6.

1.  Introduction

   Robust Header Compression (ROHC) as defined in [RFC3095] may be used

   for compression of both IPv4 and IPv6 datagrams or packets

   encapsulated with multiple IP headers.  The initial version of ROHC

   focuses on compression of the packet headers in RTP streams, while

   supporting compression of other UDP flows; however, it also defines a

   framework into which further header compression mechanisms can be

   plugged as new profiles.  Planned additions to the set of profiles

   supported by ROHC will be capable of compressing TCP transport

   protocol headers as well.

   In order to establish compression of IP datagrams sent over a PPP

   link each end of the link must agree on a set of configuration

   parameters for the compression.  The process of negotiating link

   parameters for network layer protocols is handled in PPP by a family

   of network control protocols (NCPs).  Since there are separate NCPs

   for IPv4 and IPv6, this document defines configuration options to be

   used in both NCPs to negotiate parameters for the compression scheme.

Bormann                     Standards Track                     [Page 1]

RFC 3241                     ROHC over PPP                    April 2002

   ROHC does not require that the link layer be able to indicate the

   types of datagrams carried in the link layer frames.  However, there

   are two basic types of ROHC headers defined in the ROHC framework:

   small-CID headers (zero or one bytes are used to identify the

   compression context) and large-CID headers (one or two bytes are used

   for this purpose).  To keep the PPP packets self-describing, in this

   document two new types for the PPP Data Link Layer Protocol Field are

   defined, one for small-CID ROHC packets and one for large-CID ROHC

   packets.  (This also avoids a problem that would occur if PPP were to

   negotiate which of the formats to use in each of IPCP and IPV6CP and

   the two negotiation processes were to arrive at different results.)

   A PPP ROHC sender may send packets in either small-CID or large-CID

   format at any time, i.e., the LARGE_CIDS parameter from [RFC3095] is

   not used.  Any PPP ROHC receiver MUST be able to process both small-

   CID and large-CID ROHC packets, therefore no negotiation of this

   function is required.

   ROHC assum...