31 mar 2011 kl. 15.42 skrev Worley, Dale R (Dale): > ________________________________________ > From: [email protected] > [[email protected]] On Behalf Of Nitin Kapoor > [[email protected]] > > I am facing the issue with one of my client, where my Termination is sending > 183 with SDP but my UAC is unable to hear any destination country ringback. > _______________________________________________ > > This is probably correct behavior by the client. > > There are no specifications of how the client should handle ringback. But > the best practice > is that the client should echo to the user any audio streams that it receives > during the > early dialog (at least, if the audio stream is not silence). In addition, if > the client receives > no audio streams but it has received a 180 (Ringing) response, the client > should generate > ringback to the user. > > In this case, the 183 would not trigger generation of ringback. > In regard to the SDP, you need to observe whether the Termination is sending > RTP > and if the data in the RTP is not silence. > If you are sending only ringback, I would recommend sending 180 with SDP instead of 183. If you're sending 183, I can't move my state machine to ringing state, which would help a lot of 3rd party apps. If you send ringback in 183 - they won't notice the ringing and would see the call going from calling state directly to answer, which is confusing. Sending ringback with 183 and not sending 180 is a problem for many apps.
Use 183 only if you have an operator message to play. Otherwise, add SDP to the 180 Ringing. Thanks, /O _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
