Re: [rtcweb] Use of offer / answer semantics

Emil Ivov <> Wed, 07 September 2011 12:00 UTC

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Date: Wed, 07 Sep 2011 15:02:08 +0300
From: Emil Ivov <>
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Subject: Re: [rtcweb] Use of offer / answer semantics
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На 07.09.11 03:59, Cullen Jennings написа:
> On Sep 6, 2011, at 9:49 AM, Emil Ivov wrote:
>>> 1) The media negotiations will be done using the same SDP 
>>> offer/answer semantics that are used in SIP.
>> Does this cover media format negotiation only or does it also
>> cover transport negotiation? I believe you once mentioned you were
>> a fan of "sending ICE candidates as they become available" and for
>> that to happen we'd probably need something more XMPP-like than
>> SIP/SDP-like.
> The SDP offer / answer cover both and in fact mix them together 

Yup, hence my question.

> in a way that is a bit hard to untangle,

I suppose I was (again) thinking about something along the lines of
Jingle where the separation is quite straightforward spec-wise. I do
however understand your point about how this would make it complicated
to have singnaling-only gateways with SIP ... and I do agree that this
is important, so point taken.

Thanks for explaining!

> so yes, what I am proposing here
> is that it would cover both.
> In general, I am a fan of the separating the setup of the ICE
> transport channels from the negotiation of what goes over them but I
> think we are just too late at this point to really get into doing
> that and I don't see much support for it. The hard part of this is
> how to design a signaling GW that does not require a media GW but can
> map between this and SIP. Thought we might be able to do this, and I
> think it would be architecturally cleaner, it's a lot more
> complicated to done. I don't see the work happening to make something
> like this happen in a time span where it will be relevant. I think
> people are just looking for something much closer to existing
> implementations in Chrome and Firefox.