Re: [rtcweb] Friday Agenda: Re: Friday Call details for signaling discussion

Harald Alvestrand <harald@alvestrand.no> Thu, 20 October 2011 14:44 UTC

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Date: Thu, 20 Oct 2011 16:44:42 +0200
From: Harald Alvestrand <harald@alvestrand.no>
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To: Iñaki Baz Castillo <ibc@aliax.net>
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Subject: Re: [rtcweb] Friday Agenda: Re: Friday Call details for signaling discussion
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On 10/20/11 15:31, Iñaki Baz Castillo wrote:
> 2011/10/20 Harald Alvestrand<harald@alvestrand.no>:
>> In his category of "info signalling", I would quibble a bit in that I see
>> "channel-related signalling" (a term I just invented, describing which media
>> is sent on which SSRC on which port) as distinct from "identity-related
>> signalling", where the whole question of "who am I talking to" is relevant.
>>
>> I believe "channel-related signalling" needs to be treated together with
>> "media signalling".
> Hi Harald, after re-reading this mail from you I've realized that I
> don't fully understand it.
>
> For example, a SIP INVITE has:
>
> 1) Request URI and headers, which contain the identity information,
> the destination of the request, and so. This is what I called
> "JS-Server Information Signaling".
>
> 2) An SDP, which contains media description. This is what I've called
> "JS-Server Media Signaling".
>
> Of course both are carried together (the "JS-Server Information
> Signaling" carries the "JS-Server Media Signaling").
>
> Initially I understood that your "channel-related signalling" is the
> same concept as my "JS-Server Information Signaling" (bullet 1), but
> then you said:
>
>> "channel-related signalling" (a term I just invented, describing which media
>> is sent on which SSRC on which port) as distinct from "identity-related
>> signalling", where the whole question of "who am I talking to" is relevant.
> What do you mean with "channel-related signalling"?

"which media is sent on which SSRC on which port".

This is usually sent as part of SDP, but some of Neil Stratford's 
messages have indicated a desire to separate the codec negotiation from 
the channel negotiation, so I thought it was worth pointing out that I 
think they both need to be considered in the group that you called 
"media signaling".

Hope this helps!

                    Harald