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Re: Minimizing the protocol (Re: Data API)

From: Cullen Jennings <fluffy@cisco.com>
Date: Thu, 1 Mar 2012 08:17:22 -0700
Cc: "Justin Uberti" <juberti@google.com>, <public-webrtc@w3.org>
Message-Id: <4943BD71-3538-4E0E-B61F-B9DC2D8A0E5D@cisco.com>
To: Harald Alvestrand <harald@alvestrand.no>

On Mar 1, 2012, at 2:22 AM, Harald Alvestrand wrote:

> 
> Of course, there's always the option of running the SDP on channel zero
> of the SCTP channel, a la what I've heard people claim that Facetime
> does, which would make *that* one a non-concern - but that scenario
> doesn't work for the cases where the relaying server for some reason
> needs to inspect and/or modify the SDP (of which I think I've heard
> some, but I'm not sure if any of those scenarios need data).

Hmm - All the Facetime I have seen does not use SCTP so uh, not sure what to say about that  - but I do agree it looks like in many cases Facetime does set up a communication channel between the endpoints then use that channel to directly do the SDP negotiate media. 

One of the apps I have been thinking about would use the web server to instantly bring up a data channel - this does not need much user authorization as no media is being sent so it can happen fairly early and quickly. From that point on, all SDP to add more media channels and such would be passed back and forth between the browsers over the direct data channel. (This is the "low path" from the slides I had long ago). It's not like this data channel has to be channel 0 or anything - it's just a data channel like any other. And it's not like the browser has to have any awareness of this - the JS app is just set up a data channel and using it. The only thing the JS app has to be careful of is that it does not tear down the data channel. 
Received on Thursday, 1 March 2012 15:18:11 GMT

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