Multiplexing RTP Data and Control Packets on a Single Port
RFC 5761
Internet Engineering Task Force (IETF) C. Perkins
Request for Comments: 5761 University of Glasgow
Updates: 3550, 3551 M. Westerlund
Category: Standards Track Ericsson
ISSN: 2070-1721 April 2010
Multiplexing RTP Data and Control Packets on a Single Port
Abstract
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 and RFC 3551 to describe when such multiplexing
is and is not appropriate, and it explains how the Session
Description Protocol (SDP) can be used to signal multiplexed
sessions.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5761.
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Perkins & Westerlund Standards Track [Page 1]
RFC 5761 Multiplexing RTP and RTCP April 2010
This document may contain material from IETF Documents or IETF
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material may not have granted the IETF Trust the right to allow
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Table of Contents
1. Introduction ....................................................3
2. Background ......................................................3
3. Terminology .....................................................4
4. Distinguishable RTP and RTCP Packets ............................4
5. Multiplexing RTP and RTCP on a Single Port ......................6
5.1. Unicast Sessions ...........................................6
5.1.1. SDP Signalling ......................................6
5.1.2. Interactions with SIP Forking .......................7
5.1.3. Interactions with ICE ...............................7
5.1.4. Interactions with Header Compression ................8
5.2. Any Source Multicast Sessions ..............................9
5.3. Source-Specific Multicast Sessions .........................9
6. Multiplexing, Bandwidth, and Quality of Service ................10
7. Security Considerations ........................................10
8. IANA Considerations ............................................11
9. Acknowledgements ...............................................11
10. References ....................................................11
10.1. Normative References .....................................11
10.2. Informative References ...................................12
Perkins & Westerlund Standards Track [Page 2]
RFC 5761 Multiplexing RTP and RTCP April 2010
1. Introduction
The Real-time Transport Protocol (RTP) [1] comprises two components:
a data transfer protocol and an associated control protocol (RTCP).
Historically, RTP and RTCP have been run on separate UDP ports. With
increased use of Network Address Port Translation (NAPT) [14], this
has become problematic, since maintaining multiple NAT bindings can
be costly. It also complicates firewall administration, since
multiple ports must be opened to allow RTP traffic. This memo
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