Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)
RFC 4585

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>, 
    avt mailing list <avt@ietf.org>, 
    avt chair <avt-chairs@tools.ietf.org>
Subject: Protocol Action: 'Extended RTP Profile for RTCP-based 
         Feedback(RTP/AVPF)' to Proposed Standard 

The IESG has approved the following documents:

- 'Extended RTP Profile for RTCP-based Feedback(RTP/AVPF) '
   <draft-ietf-avt-rtcp-feedback-12.txt> as a Proposed Standard
- 'Extended RTP Profile for RTCP-based Feedback - Results of the Timing 
   Rule Simulations '
   <draft-burmeister-avt-rtcp-feedback-sim-07.txt> as an Informational RFC

These documents are products of the Audio/Video Transport Working Group. 

The IESG contact persons are Allison Mankin and Jon Peterson.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-avt-rtcp-feedback-12.txt

Technical Summary

   Real-time media streams that use RTP are, to some degree, resilient 
   against packet losses.  Receivers may use the base mechanisms of 
   RTCP to report packet reception statistics and thus allow a sender 
   to adapt its transmission behavior in the mid-term as sole means 
   for feedback and feedback-based error repair (besides a few codec-
   specific mechanisms).  This document defines an extension to the 
   Audio-visual Profile (AVP) that enables receivers to provide, 
   statistically, more immediate feedback to the senders and thus 
   allow for short-term adaptation and efficient feedback-based repair 
   mechanisms to be implemented.  This early feedback profile (AVPF) 
   maintains the AVP bandwidth constraints for RTCP and preserves 
   scalability to large groups. 

   This profile establishes specific repair uses for applications, and a
   few general uses based on NACK.  It is not intended to enable RTCP to
   provide congestion control feedback.

Working Group Summary
 
  The working group supported this document.  
 
Protocol Quality
 
  The accompanying Informational document supports the claims that
  statistically the RTCP scaling of this feedback is compatible with that
   of RFC 3550.  There are also prototype implementations.  Working group
   review of the document especially covered the scalability and security
   compatibility issues.  Allison Mankin reviewed the documents for the
   IESG.