1. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG Gonzalo Camarillo Gonzalo.Camarillo@ericsson.com draft-camarillo-sip-sdp-00.txt SDP media alignment in SIP

2. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG Outline What is needed? Scenarios Cellular access 3rd party developed RTP libraries Transcoding point Proposal: Flow identification

3. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG What is needed? Systems have to be able to receive media from a single media stream, encoded in different formats during the session, in different ports and host interfaces. Better method to perform SDP media alignment in SIP than matching the nth lines.

4. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG Packet filter (TFT) Cellular Access INVITE contains different port numbers for different codecs RAB 1 RAB 2 RAB 3

5. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG 3rd party developed RTP libraries INVITE contains different port numbers for different codecs SIP User Agent RTP library supporting PCM and GSM RTP library supporting AMR UDP 20000UDP 20010 Interface

6. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG Transcoding point Cellular Wired infrastructure Transcoding point INVITE contains different IP addresses for different codecs

7. Gonzalo Camarillo Advanced Signalling Research Lab 48th IETF MMUSIC WG Proposal SDP session parameter: Flow Identifier (fid) Example: v=0 o=Laura 289083124 289083124 IN IP4 second.example.com t=0 0 c=IN IP4 222.222.222.222 m=audio 30000 RTP/AVP 0 a=fid:1 m=audio 30002 RTP/AVP 8 c=IN IP4 123.123.123.123 a=fid:1 m=audio 30004 RTP/AVP 0 a=fid:2 m=audio 30006 RTP/AVP 8 c=IN IP4 123.123.123.123 a=fid:2