Re: [rtcweb] Codec control and SDP offer/answer frequency

[Christer Holmberg <[e-mail]>]

Hi, 

>>>> Also, you would need to describe how the data channel protocol relates to negotiating being done on the signalling plane.
>>> The format of the signalling channel is defined to be outside the scope of the specification, so it's perfectly legitimate to use the data channel for that purpose - application decision!
>> Sure, applications can do whatever they want.
>>
>> But, I think it would be good to have a standardized mechanisms which works for any application. AFAIK, that was the whole purpose of the discussion in Vancouver.
>>
> Since we've settled on using SDP at the UA/Application interface,

Correct (eventhough someone in Seattle may have a different opinion ;)

> representing the data in SDP is a valid way of describing that interface
>- thus indeed making it available for use by any application written to that interface.

Correct.

> The particular worry you raised was how fast applications can do offer/answers - which is dependent on 
> how their signalling channel is implemented, and how many intermediate nodes have to process the data.

Correct.

> That's what I'm thinking will be different in the Pokerstars example than in a SIP-telephone-gateway example.

I agree that the impacts are different - but I'd like to have a solution that works in all cases.

So, if I understand you correctly: you suggest that the codec control information is transported using SDP/a=imageattr "internally" (between app and browser), but then people can send it over the wire however they want?

Regards,

Christer