[SIPForum-discussion] SDP Body in 183 Progress Message

[Sukhbir]

Hi All,

I have one doubt regarding SDP in 183 Progress Message. As i know, SDP in 183 progress is used to  play announcent to calling party (UAC). In 183 Progress with SDP body one can also mention the reason of the inclusion of SDP body. Now my question is that if Calling Party (UAC) will receive the SDP body in 183 Progress and also later in 200 (Ok) message then what would be the behaviour of Calling Party (UAC).
Should it ignore the SDP given in 200 (Ok) or it will ignore 183 Progress SDP body and proceed with 200 (Ok) SDP body? (As per RFC 3261, UAC must ignore the SDP of 200 (Ok) if it has received SDP in provisional response).
Secondly, If there will be no SDP body in INVITE message then how one can play announcent to Calling Party (UAC) if Calling party does not support reliable provisional response mechanism.

Thanks in Advance
 
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