Multiplexing Multiple RTP Sessions onto a Single Lower-Layer Transport
draft-westerlund-avtcore-transport-multiplexing-07

Network Working Group                                      M. Westerlund
Internet-Draft                                                  Ericsson
Intended status: Standards Track                           C. S. Perkins
Expires: April 24, 2014                            University of Glasgow
                                                        October 21, 2013

 Multiplexing Multiple RTP Sessions onto a Single Lower-Layer Transport
           draft-westerlund-avtcore-transport-multiplexing-07

Abstract

   This memo defines a mechanism to allow multiple RTP sessions to be
   multiplexed onto a single lower-layer transport flow (e.g., onto a
   single UDP 5-tuple).  Requirements for multiplexing RTP sessions are
   discussed, along with the trade-off between the different options.  A
   shim-based multiplexing layer is proposed, along with associated
   signalling.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Design Considerations . . . . . . . . . . . . . . . . . . . .   8
     5.1.  Location of Multiplexing Shim Header  . . . . . . . . . .   9
     5.2.  ICE and DTLS-SRTP Integration . . . . . . . . . . . . . .  10
     5.3.  Signalling Fall Back  . . . . . . . . . . . . . . . . . .  10
   6.  Specification . . . . . . . . . . . . . . . . . . . . . . . .  11
     6.1.  Shim Layer  . . . . . . . . . . . . . . . . . . . . . . .  11
     6.2.  Signalling  . . . . . . . . . . . . . . . . . . . . . . .  15
     6.3.  SRTP Key Management . . . . . . . . . . . . . . . . . . .  16
       6.3.1.  Security Description  . . . . . . . . . . . . . . . .  16
       6.3.2.  DTLS-SRTP . . . . . . . . . . . . . . . . . . . . . .  17
       6.3.3.  MIKEY . . . . . . . . . . . . . . . . . . . . . . . .  17
     6.4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  18
       6.4.1.  Secure RTP Packet with Multiplexing Shim  . . . . . .  18
       6.4.2.  Basic RTP Multiplex Negotiation in SDP  . . . . . . .  19
       6.4.3.  Advanced RTP Multiplex Negotiation in SDP . . . . . .  20
   7.  Open Issues . . . . . . . . . . . . . . . . . . . . . . . . .  20
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  21
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  21
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  21
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  21
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     11.2.  Informational References . . . . . . . . . . . . . . . .  22
   Appendix A.  Possible Solutions . . . . . . . . . . . . . . . . .  24
     A.1.  Header Extension  . . . . . . . . . . . . . . . . . . . .  24
     A.2.  Multiplexing Shim . . . . . . . . . . . . . . . . . . . .  25
     A.3.  Single Session  . . . . . . . . . . . . . . . . . . . . .  26
     A.4.  Use the SRTP MKI field  . . . . . . . . . . . . . . . . .  27
     A.5.  Use an Octet in the Padding . . . . . . . . . . . . . . .  28
     A.6.  Redefine the SSRC field . . . . . . . . . . . . . . . . .  28