Re: [rtcweb] Making progress on the signaling discussion (NB: Action items enclosed!)

Tim Panton <> Wed, 05 October 2011 11:02 UTC

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From: Tim Panton <>
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Date: Wed, 05 Oct 2011 12:05:18 +0100
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To: Iñaki Baz Castillo <>
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Subject: Re: [rtcweb] Making progress on the signaling discussion (NB: Action items enclosed!)
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On 5 Oct 2011, at 11:40, Iñaki Baz Castillo wrote:

> 2011/10/5 Tim Panton <>:
>>> Your points are perfectly valid and should indeed be covered. But I
>>> didn't want to be so explicit in my immature API suggestion. It was
>>> just an overview.
>> I guess what I was getting at was the fact that the SDP seemed
>> central to the API - I'd like something more generic and javascript
>> friendly as the central concept.
> Hi Tim. At the end you web application will receive (via the custom
> signaling) something "like" and SDP containing the media information
> offered/answered by the peer (when receiving or initiating a media
> session).

> This is: your web browser needs to know the remote IP:port, the media
> streams, supported codecs by the peer... At the end that looks like a
> SDP. And such "SDP" should be retrieved by your web application via
> some signaling protocol (on top of HTTP or WebSocket), and you will
> receive it as a JSON object, or XML, or whatever format.

Agreed. We are now getting down to the format, I'd like to see the
codec capabilities separated from the network ports , as to my mind they
are orthogonal. SDP gets into all sorts of complexity with IPv6 (e.g. happy eyeballs)
partly because it intermixes the 2 things. 

> Then you will always need to parse such "like-SDP", obtain something
> like a WebRTC.SDP object, and use it for starting/answering a session.

Yes, we will need that information to set up the session. 
I'd like the format of that information to be one that I can easily
manipulate it - selecting the relevant ports and codecs in javascript
without actually needing to parse or use SDP or being limited to offer-answer 

> You can propose a different name, something like...
> "WebRTC.SessionDescription"? :)
> but the underlying concept is the same (IMHO).

Yes, we are now discussing detail, but as they say, the devil is in the detail ;-)

> Regards.
> -- 
> Iñaki Baz Castillo
> <>