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Hello,
I
have a question regarding the SDP part of the Invite request. suppose user agent "A" wants to talk to user agent "B", he
sends a INVITE request to B. the SDP part of the invite request is as
follows, v= 0 o= A 1464112736 1464112736 IN IP4
151.209.33.190 s=Calling c=IN IP4 pgs-477 t=0 0 m=audio 2074 RTP/AVP 0 3
5 a=rtpmap:0
PCMU/8000 a=rtpmap:3 GSM/4000 a=rtpmap:5
ADPCM/4000 If user agent accepts the request and
agrees to talk to user agent A, he sends a OK response with SDP as
followed. v= 0 o= B1464112736 1464112736 IN IP4
151.209.33.194 s=Answering the
call c=IN IP4 pgs-451 t=0 0 m=audio 2074 RTP/AVP 3 5 a=rtpmap:3 GSM/4000 a=rtpmap:5
ADPCM/4000 now why can�t the user agent A send an ACK by selecting one of the coders specified in answer AS mentioned
below ? v=
0 o= A 1464112736 1464112736 IN IP4
151.209.33.190 s=Calling c=IN IP4 pgs-477 t=0 0 m=audio 2074 RTP/AVP 3 a=rtpmap:3
GSM/4000 than
analyzing the payload type (PT) header field in the RTP Packet.
Thanks
in advance
Prabha
N
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