[rtcweb] Isolating data channels (Re: Asking TLS for help with media isolation)

[Harald Alvestrand <[e-mail]>]

On 04/04/2014 10:50 PM, Martin Thomson wrote:
> Since you raise data channels, I'll note that we have no way to use 
> data channels in an isolated fashion. Thus, I conclude that if we 
> intend to make this property consistent, we should not be using data 
> channels in the same RTCPeerConnection as media streams. Of course, 
> I'm open to taking the pragmatists approach too, unless we think that 
> there is a use case for - say, file transfer - where it makes sense 
> for data to be isolated in the same way I'm proposing that media be. 

Focusing on the "should we ever isolate data channels" question:

If we ever define a protocol carried *over* data channels that is 
interpreted in the browser, not in the Javascript, and exposes a 
different API to Javascript than the datachannel API, this might make sense.

In that case, I think we should investigate whether it's possible to 
make use of the "protocol" field (put some reserved values into it 
saying "for protocols that look like *this*, Javascript can't set 
them?), it's the logical place to say "this is datachannels, but with 
some extra rules".

Wild suggestion: if you want per-track isolation properties, open up a 
data channel with a protocol called '*WebRTCIsolationInfo' and use it to 
send information about the isolation status of each track, thereby also 
providing a working example for the rule 'all data channels that have 
protocols starting with "*" are for browser internal usage'.....