5 Oct
2010
5 Oct
'10
2:47 p.m.
Hello,
you could change the SDP with UPDATE method, but 183 must be send reliable
in this case.
regards,
Andreas
2010/10/5 Iñaki Baz Castillo <ibc(a)aliax.net>
2010/10/4 Asim Riaz <ariaz78(a)gmail.com>om>:
Hi List,
Phone-1 ------->Proxy1 (kamailio)-------------->Proxy-2(3rd party)
-------------> phone 2
Calls from phone-1 to phone-2, proxy-2 is sending early media without sdp
in
provisional reply, this early media is sourced
from different port than
response (200), what port proxy-1 will use to transmit actual voice, the
source port in early media or source port in response(200) which is
different than early media.
As Daniel said Kamailio doesn't handle media (it's a SIP proxy). You
should mean "Phone-1" instead of "proxy-1".
According to the RFC about SDP (and also RFC 3261): during the same
early dialog (same To-tag) the SDP MUST NOT change. This is, if a UAS
generates a 183 (To-tag=1234) with SDP, it MUST use the same SDP in
other 183's responses and in final 200 OK response.
The client can receives multiple SDP (when there is a proxy doing
parallel forking, but each early dialog (same To-tag) MUST mantain a
fixed SDP.
So, if the client receives a different SDP in the 200 than the SDP it
received in the 183 (I mean in the *same* early-dialog / same To-tag)
then the client MUST ignore others SDP but the first one received. I
insist: I'm speaking about the SDP in the SAME early-dialog.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
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