charter for ROHC

[Vern Paxson <vern@ee.lbl.gov>]

Here is the charter we're working on for ROHC (note the slight acronym
change; an improvement as it's pronounceable [as "rock"]; Mikael is in the
process of renaming the mailing list).

There will be a meeting at Adelaide.  If the WG hasn't been approved by
then, then it will be as a BOF.

		Vern


Robust Header Compression (rohc)
--------------------------------
 
 Current Status: Proposed Working Group
 
 Chair(s):
     Mikael Degermark <micke@cs.arizona.edu>
     Carsten Bormann <cabo@tzi.org>
 
 Transport Area Director(s): 
     Scott Bradner  <sob@harvard.edu>
     Vern Paxson  <vern@aciri.org>
 
 Transport Area Advisor: 
     Vern Paxson  <vern@aciri.org>
 
 Technical Advisor(s): 
     Erik Nordmark <nordmark@eng.sun.com> 
 
 Mailing Lists: 
     General Discussion: robhc@cdt.luth.se
     To Subscribe:       majordomo@cdt.luth.se
         In Body:        subscribe
     Archive:            TBD
 
Description of Working Group:

Due to limited bandwidth, IP/UDP/RTP/TCP packets sent over cellular links
benefit considerably from header compression.  Existing header compression
schemes (RFC 1144, RFC 2508) do not perform well over cellular links due to
high error rates and long link roundtrip times, particularly as topologies
and traffic patterns become more complex.  In addition, existing schemes do
not compress TCP options such as SACK or Timestamps.

The goal of ROHC is to develop header compression schemes that perform
well over links with high error rates and long roundtrip times. The schemes
must perform well for cellular links built using technologies such as
WCDMA, EDGE, and CDMA-2000. However, the schemes should also be applicable
to other future link technologies with high loss and long roundtrip times.
Ideally, it should be possible to compress over unidirectional links.

Good performance includes both minimal loss propagation and minimal added
delay.  In addition to generic TCP and UDP/RTP compression, applications
of particular interest are voice and low-bandwidth video.

ROHC may develop multiple compression schemes, for example, some that
are particularly suited to specific link layer technologies.  Schemes
in addition to those listed in the milestones below may be added in
consultation with the area directors.

A robust header compression scheme must:

* assure that when a header is compressed and then decompressed, the
  result is semantically identical to the original;

* perform well when the end-to-end path involves more than one
  cellular link;

* support IPv4 and IPv6.

Creating more thorough requirements documents will be the first task
of the WG.

The working group shall maintain connections with other standardization
organizations developing cellular technology for IP, such as 3GPP and
3GPP-2, to ensure that its output fulfills their requirements and will be
put to good use.

In addition, the WG should develop a solid understanding of the
impact that specific error patterns have on the compression schemes,
and document guidelines to Layer 2 designers regarding what Layer 2
features work best to assist Layer 3 and Layer 4 header compression.

Goals
=====

Mar 2000 I-D on Requirements for IP/UDP/RTP header compression.

May 2000 I-D of layer-2 design guidelines.
May 2000 I-D(s) proposing IP/UDP/RTP header compression schemes.
May 2000 I-D of Requirements for IP/TCP header compression.

Jun 2000 Requirements for IP/UDP/RTP header compression submitted to
         IESG for publication as Informational.

Jul 2000 Requirements for IP/TCP header compression submitted to
         IESG for publication as Informational.
Jul 2000 Resolve possibly multiple IP/UDP/RTP compression schemes into
         a single scheme.

Aug 2000 I-D on IP/TCP header compression scheme.

Sep 2000 Layer-2 design guidelines submitted to IESG for publication
         as Informational.

Sep 2000 IP/UDP/RTP header compression scheme submitted to IESG for
	 publication as Proposed Standard.

Dec 2000 IP/TCP compression scheme submitted to IESG for publication
	 as Proposed Standard.

Jan 2001 Possible recharter of WG to develop additional compression schemes.