Support for ICE TCP (RFC 6544)

[aboba]

At IETF 89, the minutes indicate that there was consensus to make ICE-TCP (RFC 6544) a MUST implement.

See:
http://www.ietf.org/proceedings/89/minutes/minutes-89-rtcweb (Transport discussion)
http://www.ietf.org/mail-archive/web/rtcweb/current/msg11958.html

However, there is no protocol attribute in RTCIceCandidate to indicate if the candidate uses UDP or TCP.

Fix:

dictionary RTCIceCandidate {
DOMString foundation;
unsigned long priority;
DOMString ip;
unsigned short port;
RTCIceProtocol protocol;
RTCIceCandidateType type;
DOMString? relatedAddress;
unsigned short? relatedPort;
};

enum RTCIceProtocol {
"udp:,
"tcp"
}

[aboba]

Also, how do we know if a browser supports ICE-TCP or not?

[aboba]

Some ongoing discussion on the IETF RTCWEB list relating to all the implications of supporting ICE TCP:
http://www.ietf.org/mail-archive/web/rtcweb/current/msg11988.html

One related question is whether the TCP/UDP transport needs to be exposed anywhere else other than in the RTCIceCandidate object (e.g. RTCIceServer object, etc.).

[martinthomson]

One related question is whether the TCP/UDP transport needs to be exposed anywhere else other than in the RTCIceCandidate object (e.g. RTCIceServer object, etc.).

Even if it seemed like a good idea, I'd want to resist creating externalities in that way. If the browser can't handle the consequences of using TCP rather than UDP without pushing its problems on the using application, then I'd rather we didn't include this feature at all. My guess is that it's manageable without more API hooks.

[aboba]

OK. Looks like the enum is sufficient for now.