Technical Summary
This memo discusses issues that arise when multiplexing RTP data
packets and RTP control protocol (RTCP) packets on a single UDP port.
It updates RFC 3550 to describe when such multiplexing is, and is
not, appropriate, and explains how the Session Description Protocol
(SDP) can be used to signal multiplexed sessions.
Working Group Summary
This document represents a solid consensus of the AVT Working Group,
with informal concurrence of the MMUSIC and BEHAVE Working Groups.
Following the initial proposal, the major issue subsequently considered
and resolved was how to negotiate the multiplexing capability and
achieve fail-safe behavior. The decision was to provide a new SDP
attribute to signal the multiplexing capability explicitly. There was
also some discussion of how to signal bandwidth requirements. The
outcome was a decision to include allowance for RTCP traffic in the
b=AS: value.
Document Quality
The document has attracted considerable interest because it makes NAT
traversal easier. Jonathan Rosenberg, author of the ICE document,
reviewed the proposal in terms of its interaction with ICE and provided
related text. Randell Jesup deserves special mention for his careful
reviews of successive versions of the document and persistence in
analysis of the associated signaling issues.
Personnel
Document Shepherd was Tom Taylor.
Responsible Area Director was Cullen Jennings.
Note to RFC Editor
Please change this document so that it also updates RFC 3551.