Re: [rtcweb] Multiplexing using the same port number for multiple media descritions
Magnus Westerlund <magnus.westerlund@ericsson.com> Wed, 31 August 2011 11:13 UTC
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Date: Wed, 31 Aug 2011 13:15:09 +0200
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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To: Harald Alvestrand <harald@alvestrand.no>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] Multiplexing using the same port number for multiple media descritions
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On 2011-08-30 17:15, Harald Alvestrand wrote: > On 08/30/11 13:21, Christer Holmberg wrote: > In that case, we have an RTP spec problem, not just an SDP problem: RTP > "straight" claims to identify sessions by destination address + port > (RFC 3550 section 5.2, for instance). In normal unicast / point-to-point > usage, we expect all packets to come from the same address + port too, > but RFC 3550 doesn't say that. > > I don't know if this is an issue. If it is an issue, sender might have > to start over. > Well, that is one way to id the session a flow is supposed to end up in. If I understand the situation you are proposing would still allow the inviting party to use 5-tuples to identify flows coming into each session. This as you will learn from the ICE processing each peers visible source address for each session through the ICE plus signaling. And I don't think we have a spec problem if we like to use a session transport setup that looks like this. Session 1 A:10000 <---> B:20000 Session 2 A:10000 <---> B:30000 As this provides different 5-tuples it does fulfill for example the following from section 5.2 of RFC3550: For example, in a teleconference composed of audio and video media encoded separately, each medium SHOULD be carried in a separate RTP session with its own destination transport address. At least if you interpret "own destination transport address" as the full five tuple rather than a 3-tuple of destiantion address, port and protocol. Cheers Magnus Westerlund ---------------------------------------------------------------------- Multimedia Technologies, Ericsson Research EAB/TVM ---------------------------------------------------------------------- Ericsson AB | Phone +46 10 7148287 Färögatan 6 | Mobile +46 73 0949079 SE-164 80 Stockholm, Sweden| mailto: magnus.westerlund@ericsson.com ----------------------------------------------------------------------
- [rtcweb] Multiplexing using the same port number … Christer Holmberg
- Re: [rtcweb] Multiplexing using the same port num… Justin Uberti
- Re: [rtcweb] Multiplexing using the same port num… Harald Alvestrand
- Re: [rtcweb] Multiplexing using the same port num… Christer Holmberg
- Re: [rtcweb] Multiplexing using the same port num… Christer Holmberg
- Re: [rtcweb] Multiplexing using the same port num… Magnus Westerlund
- Re: [rtcweb] Multiplexing using the same port num… Christer Holmberg
- Re: [rtcweb] Multiplexing using the same port num… Harald Alvestrand
- Re: [rtcweb] Multiplexing using the same port num… Christer Holmberg