Forum Discussion
Teams Direct routing media bypass mode ICE controlled
AlainCPlease check https://tools.ietf.org/html/rfc5245#page-75
"ice-lite" is a session-level attribute only, and indicates that an agent is a lite implementation.
In your trace you have it within the media part , once you have it in the right position before m=audio
you will get the correct controlled state and nomination.
I see exactly the same issue. The result is that, for inbound calls from PSTN, the RTP flows comes directly from the Teams client to SBC but a media relay is used for the other way (sbc to Teams user). And there is no RE-INVITE sent to the SBC.
Did you get an answer from MS ?
AlainCYes make sure you have a=ice-lite in all requests sent to MS Teams to make sure SBC is in controlled state while Teams endpoints are full-ICE with controlling attribute.
afouad5 Thanks . yes, a=ice-lite is included in the initial SIP INVITE sent by the SBC. And I still see ICE-CONTROLLED in the stun binding resquests coming from the called Teams agent.
So, the issue on your setup is it fixed ? Does your SBC receive a RE-INVITE (with a=remote-candidates) and c= with the remote Teams agent IP address after it received the 200 OK ? Is it possible to have a trace of a call ?
note : the issue is only for calls that are initiated by the SBC to a Teams agent. It works as expected for calls from Teams agent to SBC : SBC receives stun requests with ICE-CONTROLLING, RE-INVITE received by SBC (after it sends 200 OK) with c= indicating the Teams agent remote address.
In this link https://docs.microsoft.com/en-us/openspecs/office_protocols/ms-sdpext/fca7a99e-5408-47a6-9793-5be0800df1a4 It is written "This means that the caller MUST send the ICE re-INVITE". I do not know if this is relevant for a SBC which supports only ice-lite but I was wondering if the SBC should send such RE-INVITE (maybe will it receive the remote IP address in the 200 OK/c= attribute) and what to indicate in a=remote-candidates attribute