RFC 3388 (rfc3388) - Page 1 of 21

Grouping of Media Lines in the Session Description Protocol (SDP)

Alternative Format: Original Text Document
Next >
Network Working Group                                       G. Camarillo
Request for Comments: 3388                                   G. Eriksson
Category: Standards Track                                      J. Holler
                                                                Ericsson
                                                          H. Schulzrinne
                                                     Columbia University
                                                           December 2002


   Grouping of Media Lines in the Session Description Protocol (SDP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines two Session Description Protocol (SDP)
   attributes: "group" and "mid".  They allow to group together several
   "m" lines for two different purposes: for lip synchronization and for
   receiving media from a single flow (several media streams) that are
   encoded in different formats during a particular session, on
   different ports and host interfaces.

Table of Contents

   1. Introduction..................................................  2
   2. Terminology...................................................  2
   3. Media Stream Identification Attribute.........................  3
   4. Group Attribute...............................................  3
   5. Use of "group" and "mid"......................................  3
   6. Lip Synchronization (LS)......................................  4
      6.1 Example of LS.............................................  5
   7. Flow Identification (FID).....................................  5
      7.1 SIP and Cellular Access...................................  6
      7.2 DTMF Tones................................................  6
      7.3 Media Flow Definition.....................................  6
      7.4 FID Semantics.............................................  7
          7.4.1 Examples of FID.....................................  8
      7.5 Scenarios that FID does not Cover........................  11



Camarillo et. al.           Standards Track
Next >