[EMAIL PROTECTED] wrote:
> Hi All,
>
> I am working on the development of SIP user agent. I have got a problem in
> SDP negotiation. My problem is as follows.
>
> Suppose user agent A sends an INVITE request to user agent B with SDP as
> follows
>
> v=0
> o=A 1907016736 1907016736 IN IP4 151.209.33.171
> s=Calling User
> c=IN IP4 PGS-451
PGS-451 is not a valid IPv4 address.
> t=0 0
> m=audio 2074 RTP/AVP 3 5
> a=rtpmap:3 GSM/4000
> a=rtpmap:5 GSM/8000
>
> Then user agent B sends OK response along with the following SDP
> v=0
> o=B 1907015736 1907015736 IN IP4 151.209.33.190
> s=Answering the call
> c=IN IP4 pgs-477
pgs-477 is not a valid ipv4 address.
> t=0 0
> m=audio 0 RTP/AVP 3
> m=audio 5 RTP/AVP 5
>
This is wrong. THe number of m lines in the answer must match the number
in the offer.
>
> Now since it is understood that user agent B does not support payload of
> type 3 what should be the response of
>
> is it user agent A has to send a ACK to the user agent B or send a 3xx
> response? please give me a clarification.
It has to ACK. SIP signaling is a three way handshake for call setups,
INVITE/2xx/ACK. The UAC can not send anything else but ACK. In this
case, the SDP is invalid, so the UAC should probably immediately
termainte the call with BYE.
-Jonathan R.
--
Jonathan D. Rosenberg, Ph.D. 72 Eagle Rock Avenue
Chief Scientist First Floor
dynamicsoft East Hanover, NJ 07936
[EMAIL PROTECTED] FAX: (973) 952-5050
http://www.jdrosen.net PH: (973) 952-5000
http://www.dynamicsoft.com
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