Re: [rtcweb] How to determine TLS roles?

On 10 Feb 2014, at 13:29, Christer Holmberg <christer.holmberg@ericsson.com> wrote:

> Hi,
> 
> If I understand correctly, in RTCWEB we are going to use a single DTLS association for two things:
> 
> 1)      Key exchange for SRTP
> 2)      The data channel
> 
> Now, this means that there needs to be a generic way to determine the TLS roles.
> 
> In WEBRTC, how are the TLS roles determined?

That was the subject of a rant of mine.

I think the correct answer is that the party that ends up being IceControlling then becomes the
DTLS client. Typically the initiator of a session is IceControlling. 

However the recent addition of 
a=setup:passive 
to chrome's SDP clouds the story somewhat, allowing an IceController to say that it is DTLS passive
and allow the non-initiator to be the DTLS client.

Ostensibly this is to support early media - where the receiver of a call wishes to send media before the
initiator does.

As I said (rather intemperately) this added complexity is not worth the benefit.

Tim.

http://webrtchacks.com/tim-rant/

> 
> Regards,
> 
> Christer
> 
> 
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Tim Panton - Web/VoIP consultant and implementor
www.westhawk.co.uk