RObust Header Compression (ROHC): A Compression Profile for IP
RFC 3843
| Document | Type |
RFC - Proposed Standard
(June 2004; No errata)
Updated by RFC 4815
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 3843 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Allison Mankin | ||
| Send notices to | (None) | ||
Network Working Group L-E. Jonsson
Request for Comments: 3843 G. Pelletier
Category: Standards Track Ericsson
June 2004
RObust Header Compression (ROHC): A Compression Profile for IP
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 (2004).
Abstract
The original RObust Header Compression (ROHC) RFC (RFC 3095) defines
a framework for header compression, along with compression protocols
(profiles) for IP/UDP/RTP, IP/ESP (Encapsulating Security Payload),
IP/UDP, and also a profile for uncompressed packet streams. However,
no profile was defined for compression of IP only, which has been
identified as a missing piece in RFC 3095. This document defines a
ROHC compression profile for IP, similar to the IP/UDP profile
defined by RFC 3095, but simplified to exclude UDP, and enhanced to
compress IP header chains of arbitrary length.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. ROHC IP Compression (Profile 0x0004) . . . . . . . . . . . . . 3
3.1. Static Chain Termination . . . . . . . . . . . . . . . . 3
3.2. Handling Multiple Levels of IP Headers . . . . . . . . . 3
3.3. Constant IP-ID . . . . . . . . . . . . . . . . . . . . . 4
3.4. Additional Mode Transition Logic . . . . . . . . . . . . 6
3.5. Initialization . . . . . . . . . . . . . . . . . . . . . 8
3.6. Packet Types . . . . . . . . . . . . . . . . . . . . . . 8
3.7. The CONTEXT_MEMORY Feedback Option . . . . . . . . . . . 10
4. Security Considerations. . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
7. Normative References . . . . . . . . . . . . . . . . . . . . . 11
Jonsson & Pelletier Standards Track [Page 1]
RFC 3843 A ROHC Profile for IP June 2004
Appendix A. Detailed Procedures for Canceling Mode Transitions. . 12
A.1. Transition from Optimistic to Reliable Mode. . . . . . . 12
A.2. Transition from Unidirectional to Reliable Mode. . . . . 13
A.3. Transition from Reliable to Optimistic Mode. . . . . . . 13
A.4. Transition Back to Unidirectional Mode . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
The original RObust Header Compression (ROHC) RFC [RFC-3095] defines
a framework for header compression, along with compression protocols
(profiles) for IP/UDP/RTP, IP/ESP (Encapsulating Security Payload),
IP/UDP, and also a profile for uncompressed packet streams. The
profile for uncompressed data was defined to provide a means to
encapsulate all traffic over a link within ROHC packets. Through
this profile, the lower layers do not have to provide multiplexing
for different packet types, but instead ROHC can handle any packet
stream, even if compression profiles for all kinds of packet streams
have not yet been defined or implemented over the link.
Although the profile without compression is simple and can tunnel
arbitrary packets, it has of course a major weakness in that it does
not compress the headers at all. When considering that normally all
packets are expected to be IP [RFC-791, RFC-2460] packets, and that
the IP header often represents a major part of the total header, a
useful alternative to no compression would for most packets be
compression of the IP header only. Unfortunately, such a profile was
not defined in [RFC-3095], and this has thus been identified as an
important missing piece in the ROHC toolbox.
This document addresses this missing compression support and defines
a ROHC compression profile for IP [RFC-791, RFC-2460] only, similar
to the IP/UDP profile defined by [RFC-3095], but simplified to
exclude UDP. Due to the similarities with the IP/UDP profile, the IP
compression profile is described based on the IP/UDP profile, mainly
covering differences. The most important differences are a different
way of terminating the static header chain, and the capability of
compressing IP header chains of arbitrary length.
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