Re: [rtcweb] Multiplexing using the same port number for multiple media descritions
Christer Holmberg <christer.holmberg@ericsson.com> Wed, 31 August 2011 13:34 UTC
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From: Christer Holmberg <christer.holmberg@ericsson.com>
To: "rtcweb@ietf.org" <rtcweb@ietf.org>
Date: Wed, 31 Aug 2011 15:35:56 +0200
Thread-Topic: [rtcweb] Multiplexing using the same port number for multiple media descritions
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Subject: Re: [rtcweb] Multiplexing using the same port number for multiple media descritions
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Hi, Another advantage of the same-port-number solution is that the browser doesn't need to reserve more than one port (including candidate collection etc) - no matter whether multiplexing will eventually be used or not. Regards, Christer ________________________________ From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On Behalf Of Christer Holmberg Sent: 30. elokuuta 2011 14:22 To: rtcweb@ietf.org Subject: [rtcweb] Multiplexing using the same port number for multiple media descritions Hi, One possible alternative solution for SDP multiplex negotiation could be based on the assumption of using the same port number in multiple SDP m- lines (yes, I know SDP does not allow it, and I will come back to that). Something like: SDP offer: m=audio 10000 ... a=rtpmap ... a=rtpmap ... m=video 10000 ... a=rtpmap ... a=rtpmap ... SDP answer (multiplex supported/accepted): m=audio 20000 ... a=rtpmap ... a=rtpmap ... m=video 20000 ... a=rtpmap ... a=rtpmap ... SDP answer (multiplex not-supported/rejected): m=audio 20000 ... a=rtpmap ... a=rtpmap ... m=video 30000 ... a=rtpmap ... a=rtpmap ... MAYBE there is also a need to use some kind of grouping, in which case it could look something like (borrowing some terminology from Harald): SDP offer: a=group:TOGETHER foo bar m=audio 10000 ... a=mid:foo a=rtpmap ... a=rtpmap ... m=video 10000 ... a=mid:bar a=rtpmap ... a=rtpmap ... SDP answer (multiplex supported/accepted): m=audio 20000 ... a=rtpmap ... a=rtpmap ... a=mid:foo m=video 20000 ... a=mid:bar a=rtpmap ... a=rtpmap ... SDP answer (multiplex not-supported/rejected): m=audio 20000 ... a=rtpmap ... a=rtpmap ... m=video 30000 ... a=rtpmap ... a=rtpmap ... An ISSUE with this solution is of course that SDP does not allow for it. However, we could always say that browsers must support it, in which case it should work fine in direct browser-to-browser cases. When interworking with legacy, I guess two things can happen: 1. The offer is acctepted, with different port number in the answer, and multiplex won't be used (see example above) 2. The offer is rejected. In this case, the fallback would be that the browser sends a new offer, with different port numbers, and multiplex won't be used. Regards, Christer
- [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