[MMUSIC] Re : SDP extensions for Explicit Asymmetric RTP

["Ingemar Johansson S" <ingemar.s.johansson at ericsson.com>]

Hi

While the proposal below is very tempning it is not valid according to RFC2327. The only way to solve asymmetry in a general fashion is to define several media lines.

I sketched on a general solution to asymmetry issues some time ago
http://tools.ietf.org/html/draft-johansson-mmusic-asymmetric-media-00
The whole thing was meant to be a partly backwards compatible extension to SDPCapNeg, the interest was however quite low. Still I believe that questions like these will show up more in the future and then it would be good to have a generic solution.

Regards
Ingemar


>Hi all,

>I apologize if this has already been discussed.

>I am thinking a little about "SDP extensions for Explicit Asymmetric RTP".
>It is very simple extensions as below.

>   m=audio 62986 RTP/AVP 0 4 18
>   a=rtpmap:0 PCMU/8000
>   a=rtpmap:4 G723/8000
>   a=rtpmap:18 G729/8000
>   a=fmtp:4 sendonly
>   a=fmtp:18 recvonly
>   a=fmtp:4 ptime:30
>   a=fmtp:18 ptime:20

>Any thoughts on this extensions?

>Regards,
>Shinji

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Ingemar Johansson 
Senior Research Engineer, IETF "nethead" 
EAB/TVK - Multimedia Technologies 
Ericsson Research Ericsson AB 
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