Re: [rtcweb] CNAMEs and multiple peer connections
Magnus Westerlund <magnus.westerlund@ericsson.com> Mon, 10 March 2014 14:42 UTC
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Date: Mon, 10 Mar 2014 15:42:12 +0100
From: Magnus Westerlund <magnus.westerlund@ericsson.com>
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To: Martin Thomson <martin.thomson@gmail.com>, Dan Wing <dwing@cisco.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] CNAMEs and multiple peer connections
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On 2014-03-08 07:48, Martin Thomson wrote: > On 7 March 2014 20:14, Dan Wing <dwing@cisco.com> wrote: >> About half a year ago, AVTCORE published an updated recommendation >> for CNAME as RFC7022. Is its guidance insufficient? > > Necessary, but not sufficient. Unfortunately, the definition of a > "session", while sufficient for the description in 7022, is not > quite precise enough for this use case. The implication there is > that it means "RTP session", which is both not at the right level of > granularity, and not directly actionable. So, within a PeerConnection one have one or more RTP sessions, depending on how one configures it. That RTP session MAY be interconnected with other PeerConnection's RTP sessions by a middlebox. As long as this is different end-points PCs there is little issues. The interesting case here is if one end-point connects multiple PCs to the same middlebox and starts seeing its own traffic due to the middlebox not being built for this usage and the JS programmer thinks this is okay to do. The end-point can always detect this, as it knows all its used CNAMEs, and can note that they are looped back to itself if this check is implemented. If one have the same CNAME is both PC's RTP session instances the RTP stack is more likely to detect this without code changes as a loop. The only reason I can see for having multiple PCs being connected to the same middlebox would be if that makes the setup of QoS simpler, but I think MST individual RTP sessions within the context of one PC is more straight forward to ensure that one have unique 5-tuples per media stream. > > I also note this little gem: > > A longer-term persistent RTCP CNAME is sometimes useful to > facilitate third-party monitoring, consistent with [RFC3550]. Yes, but that is clearly not suitable for WebRTC. Cheers Magnus Westerlund ---------------------------------------------------------------------- Services, Media and Network features, Ericsson Research EAB/TXM ---------------------------------------------------------------------- Ericsson AB | Phone +46 10 7148287 Färögatan 6 | Mobile +46 73 0949079 SE-164 80 Stockholm, Sweden | mailto: magnus.westerlund@ericsson.com ----------------------------------------------------------------------
- [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Harald Alvestrand
- Re: [rtcweb] CNAMEs and multiple peer connections Dan Wing
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Dan Wing
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti
- Re: [rtcweb] CNAMEs and multiple peer connections Watson Ladd
- Re: [rtcweb] CNAMEs and multiple peer connections Martin Thomson
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti
- Re: [rtcweb] CNAMEs and multiple peer connections Watson Ladd
- Re: [rtcweb] CNAMEs and multiple peer connections Magnus Westerlund
- Re: [rtcweb] CNAMEs and multiple peer connections Justin Uberti