Re: [rtcweb] Use of offer / answer semantics

Tim Panton <> Thu, 08 September 2011 09:38 UTC

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From: Tim Panton <>
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Date: Thu, 08 Sep 2011 10:40:46 +0100
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To: Cullen Jennings <>
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Subject: Re: [rtcweb] Use of offer / answer semantics
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On 7 Sep 2011, at 02:45, Cullen Jennings wrote:
… snipped inc comment on excessive inlining ;-) …..
> I'm not assuming anything about this being the primary use case. I'm assuming it is an important use case. If it were not, we would do this totally differently probably starting with not using RTP, certainly not using SDP or offer/answer, and I'd argue for a p2p (in the overlay network sense of the term) form rendezvous - there would be people on the list point out if we use used HIP, everything would be done. We are not doing that because it is an import use case.  The reason it is important is because that is the way we connect this to the existing voice and video communication infrastructure that currently supports well over 4 billion users and probably over 5 billion. 

Just to be pedantic, it is _a_ way we can connect to the 5 billion. Since a growing number of them are on GSM capable equipment, that could be seen as an argument for an Um or SS7 or IMS stack. 

My real point being that we can't expect a RTC capable web browser to be able to directly address anything but
a tiny proportion of them. A browser in an enterprise _might_ be able to connect RTP point-to-point with a SIP desk phone in the same enterprise, but only if it was on the same VLAN, which isn't common practice.

So whilst it is an important use case, it is not going to see much actual use (IMHO).

Tim (speaking for himself)