6 aug 2009 kl. 12.49 skrev Vivek Batra: >>> Greetings, >>> I am wondering if the below scenario is valid or not. >>> >>> <-- 183 (with SDP) then, >>> <-- 180 (without SDP) >> >> Yes it's. >> However it depends in UAC behaviour on how to render it to the human >> (it could choose to render the early-media comming from the same 183, >> or it could choose to render internal ringing due to the 180). > > I would suggest stopping the playback of audio when you receive the > 180 with SDP and revert to the ringing tone. Users does not like > silence and sending an 180 would suggest that there's no more early > media to me. > > [Vivek] - With some ITSP's, 183 Session Progress is sent (with SDP) > to play > the music (something like, please wait while your call is on wait) > when > actual called party is busy. However, 180 Ringing is sent as soon as > call > has been placed to called party and called party is ringing. > ITSP does not disconnect the media after sending 180 Ringing instead > start > playing Ring Back Tone (RBT) to caller. Hence, in either manner > while caller > disconnects the media or not on receipt of 180 Ringing (without > SDP), RBT > will be played to caller either locally (if caller honors 180 > Ringing) or by > remote server (if caller does not honors 180 Ringing). > I believe in having a check in application to check whether any RTP > stream > is still there or not after receiving 180 Ringing (without SDP). If > no RTP > is coming, then only 180 Ringing should be honored to play RBT > locally else > RTP from ITSP should be played. > That sounds like a good pragmatic approach.
On a related topic. What should one do in this case? <--- 183 with sdp from UA 1 (10 secs) <--- 183 with sdp from UA 2 (5 secs) <--- 180 ringing from UA 3 <--- 200 OK from UA 3 From testing, different devices do very different things. /O :-) _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
