Re: [SIP] draft-camarillo-sip-sdp-00.txt
Michael Thomas <mat@cisco.com> Thu, 12 October 2000 14:37 UTC
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From: Michael Thomas <mat@cisco.com>
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To: Gonzalo Camarillo <Gonzalo.Camarillo@lmf.ericsson.se>
Cc: "Culpepper, Bert" <bert.culpepper@intervoice-brite.com>, Rohan Mahy <rohan@cisco.com>, Jonathan Rosenberg <jdrosen@dynamicsoft.com>, sip@lists.bell-labs.com, Henning Schulzrinne <hgs@cs.columbia.edu>, mmusic <confctrl@ISI.EDU>
Subject: Re: [SIP] draft-camarillo-sip-sdp-00.txt
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Date: Thu, 12 Oct 2000 07:22:06 -0700
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Gonzalo Camarillo writes: > I would like my session description to look like: > > v=0 > o=John 289085535 289085535 IN IP4 first.example.com > t=0 0 > c=IN IP4 111.111.111.111 > m=audio 20000 RTP/AVP 0 > a=fid:1 > m=audio 20002 RTP/AVP 8 > a=fid:1 > > If an implementation does not understand the fid attribute it will try > to mix the audio streams. Since one is "empty" all the time, doing this > is not really a big deal. Thus, backwards compatibility is not a > concern. > > Do you have any concerns with this approach? The main problem I see is with the interaction with QoS reservations. Namely, that you'd expect the receiver to book reservations for both flows. Doing: m=audio 20000 RTP/AVP 0 8 on the other hand only implies that you book the ceil() of both flows. Why is it so advantageous to segregate these into two streams? The implicit coupling you're after seems like it's not well handled by SDP right now, and I'd bet that this would be better taken up as a working item for SDPng (if not already there) because my understanding is that explicit audio synch with video is also problematic in SDP right now, which is sort of similar. Mike _______________________________________________ SIP mailing list SIP@lists.bell-labs.com http://lists.bell-labs.com/mailman/listinfo/sip
- Re: [SIP] draft-camarillo-sip-sdp-00.txt Gonzalo Camarillo
- Re: [SIP] draft-camarillo-sip-sdp-00.txt Michael Thomas
- RE: [SIP] draft-camarillo-sip-sdp-00.txt Culpepper, Bert
- Re: [SIP] draft-camarillo-sip-sdp-00.txt Gonzalo Camarillo
- [SIP] draft-camarillo-sip-sdp-00.txt Culpepper, Bert
- Re: [SIP] draft-camarillo-sip-sdp-00.txt Gonzalo Camarillo
- Re: [SIP] draft-camarillo-sip-sdp-00.txt Gonzalo Camarillo
- RE: [SIP] draft-camarillo-sip-sdp-00.txt Jonathan Rosenberg