Subject: [AVT] Protocol Action: Enhanced Compressed RTP (CRTP) for links with high delay, packet loss and reordering to Proposed Standard

From: The IESG <[email-masked]>
Date: Fri, 04 Apr 2003 17:57:48 -0500

The IESG has approved the Internet-Draft 'Enhanced Compressed RTP
(CRTP) for Links with High Delay, Packet Loss and Reordering'
<draft-ietf-avt-crtp-enhance-07.txt> as a Proposed Standard. This
document is the product of the Audio Video Transport Working Group.
The IESG contact persons are Allison Mankin and Jon Peterson.

 Technical Summary

 This document describes a header compression scheme for point to point
 links with packet loss and long delays. It is based on Compressed
 Real-time Transport Protocol (CRTP), the IP/UDP/RTP header compression
 described in RFC 2508. Original CRTP does not perform well on such
 links: packet loss results in context corruption and due to the long
 delay, excessive packets are discarded before the context is
 repaired. To correct the behavior of CRTP over such links, a few
 extensions to the protocol are specified here. The extensions aim to
 reduce context corruption by changing the way the compressor updates
 the context at the decompressor: updates are repeated and include
 updates to full and differential context parameters. With these
 extensions, ECRTP performs well over links with packet loss, packet
 reordering and long delays.

 The distinction is made that ECRTP is robust for links with reordering
 such as tunnels and multihop, and it is also robust for cellular links
 with high loss but that ROHC (RFC 3095) is expected "to be the preferred
 compression mechanism over links where compression efficiency is important"
 and packet misordering is infrequent.

 Working Group Summary

 The working group supported advancement of this document. There were
 no Last Call concerns with the document, but Area Director comments
 resulted in clarifications on IPv6, Security considerations, and applicability.

 Protocol Quality/Review

 This document was reviewed for the IESG by Allison Mankin.
 The Transport Area seeks information about implementations of ECRTP and
 their performance.
_______________________________________________
Audio/Video Transport Working Group
[email-masked]
https://www1.ietf.org/mailman/listinfo/avt