I’m not having much luck getting the counterpath softphones, either Bria 3 or XLite 4, to work with the Google Voice media server. The problem is the counterpath softphones don’t seem to be implementing ICE properly or perhaps are implementing an earlier version. The specific issue is they don’t send a STUN binding request on the RTP socket and instead launch straight into sending their own RTP stream. The Google Voice server isn’t interested in RTP until it’s done the STUN binding request exchanges. Update: it was my own malformed SDP packet that stopped the XLite from working properly. Once that was fixed the XLite did send a STUN request as part of the media initialisation. The problem then became the Google Voice server not recognising the STUN request because it implements an earlier version of STUN/ICE and it doesn’t recognise the STUN attributes set by the XLite.

I tried out the free version of the Zoiper softphone as well but it doesn’t look like it support any version of ICE so I didn’t get anywhere with it either.

If anyone is aware of a SIP softphone that supports ICE please let me know.

Update: Thanks to Avi Marcus I tried out the Blink softphone which like the XLite also supports ICE. It also send the STUN binding request to initialise the media and as with the XLite it’s requests were rejected as malformed by the Google Talk/Voice XMPP server due to the newer STUN attributes.

Unless something else crops up I think that’s pretty much the end of any attempt to integrate Google Voice XMPP calls with sipsorcery for a while. To work around the mismatch in STUN/ICE versions between softphones that do support ICE and Google Talk/Voice would mean proxying the media and that’s not something the sipsorcery service is geared for. The Google Talk developer document does state they intend to implement the latest versions of Jingle and that would mean also supporting the latest version of ICE. When that happens there will be more options to translate between SIP and XMPP with Google Talk/Voice.