Hi Naveen, Media can Start before the final response, where you get announcements.. before your call is established. This is seen more in common with PSTN Interworking.
To your question:If the "Answer" in provisional and Final response be different. No,Answer cannot be different. "Answer" from the first response should be taken.Because there can be only one offer/answer exchange in a SIP transaction. This issue was discussed in the mailing some time back: Pl refer : http://130.230.52.14/list-archive/sip/msg09569.html HTH, Sreeram. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Friday, October 28, 2005 4:57 PM To: [email protected] Subject: [Sip-implementors] Offer-Answer in SIP Hi all, As per the RFC, if the "Offer" is send in INVITE, then the "Answer" can be received in any of the provisional responses( 180,183 ..) or a 200 OK.So then theoretically, media can start flowing in even if a final response is not received( if the Answer comes in a provisional response).Is this behavior correct? Moreover, what if the Answer comes in a provisional response and then 200 OK also returns an Answer. Can both the Answers differ( lets say as per the proviosnal reponse G.711 is the chosen codec and then 200 OK returns G.729 as the chosen codec). Thanks Naveen 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. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors 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. _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
