RE: [Sip-implementors] Offer-answer queries

[nataraju.alilaghatta]

Title: Message

Regards, Nataraju A.B. -----Original Message----- From: Prabha [mailto:[EMAIL PROTECTED] Sent: Monday, December 15, 2003 11:09 AM To: Nataraju Alilaghatta (WT01 - TELECOM & INTER-NETWORKING SOLUTIONS); Ranjit Avasarala (WT01 - TELECOM & INTER-NETWORKING SOLUTIONS); [EMAIL PROTECTED] Subject: Re: [Sip-implementors] Offer-answer queries   Hello,   Yes, i do agree with you that when both the parties support codec 3 and 5, the RTP payload also would be either 3 or 5 But i wanted to know whether the offeror could still send an ACK with sdp details by selecting one of the coders.   Because i did come across some statements saying ACK should not be sent with sdp details if the offer is already sent in an INVITE.   Is the following INVITE-200OK-ACK handshake against the RFC 3264 implementation   OFFEROR (SDP details in INVITE)  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   ANSWERER(SDP details in 200 OK )    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   OFFEROR (SDP details in ACK)   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   If the above handshake is not allowed, then looking into the payload type in the RTP header is the the only way to find out for the negotiated codec ?   [Natraj] in this case Offerer no needs to send the SDP info. It’s the design issue how to identify whether the SDP in 2xx is an answer to one in Invite or New Offer.   Just for example when Offerer send SDP info in Invite he needs retain that information (of Offer I been sent out, a flag may be) then no need to send the SDP info in ACK. Else send the answer to the offer in 2xx.   This is no where mentioned in RFC it’s purely Implementation issue.   Correct me if I am wrong….   Confidentiality Notice The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain confidential or privileged information. If you are not the intended recipient, please notify the sender at Wipro or [EMAIL PROTECTED] immediately and destroy all copies of this message and any attachments.

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