I hope this holds good, even if there is change of offer/answer in between (18X reliable & 200 ok). My doubt is that, the UAS can still send the same session description in 200 ok (of Invite) as in 18x (reliable). This session description could be different from what was exchanged previously using PRACK/UPDATE. Or there should not be any session description at all in 200 ok (of Invite) in this case? Or if present, the UAC should ignore it?
Thanks, kumar From: Vivek Talwar [mailto:vivek.tal...@globallogic.com] Sent: Friday, July 27, 2012 4:51 PM To: Kumar Ramadoss (WT01 - GMT-Telecom Equipment) Cc: sip-implementors@lists.cs.columbia.edu Subject: Re: [Sip-implementors] Offer/Answer model query Hi Kumar, Yes you are correct. The UAS can not initiate subsequent offer if it has already sent or received answer of offer in initial transaction. Reference Refer RFC 3261: Once the UAS has sent or received an answer to the initial offer, it MUST NOT generate subsequent offers in any responses to the initial INVITE. This means that a UAS based on this specification alone can never generate subsequent offers until completion of the initial transaction. Thanks and Regards, Vivek Talwar On Fri, Jul 27, 2012 at 4:41 PM, <kumar.ramad...@wipro.com<mailto:kumar.ramad...@wipro.com>> wrote: Hi *, Whether below mentioned scenarios correct from Offer/Answer model point of view ? 1. INVITE/18x (Reliable) for Offer/Answer1. 200 OK (INVITE)/ACK for Offer/Answer2. 2. INVITE/18x (Reliable) for Offer/Answer1. PRACK/200 OK (PRACK) for Offer/Answer2. 200 OK (INVITE)/ACK for Offer/Answer3. 3. INVITE/18x (Reliable) for Offer/Answer1. UDPATE/200 OK (UPDATE) for Offer/Answer2. 200 OK (INVITE)/ACK for Offer/Answer3. 4. INVITE/18x (Reliable) for Offer/Answer1. PRACK/200 OK (PRACK) for Offer/Answer2. UDPATE/200 OK (UPDATE) for Offer/Answer3. 200 OK (INVITE)/ACK for Offer/Answer4. My doubt is mainly for the case, where Offer is received in 200 OK (of INVITE) (later Answer in ACK), as already the offer/answer exchange has happened for that SIP transaction via INVITE/18x(reliable). I have read somewhere, that there should be only one offer/answer exchange for a SIP transaction. Please clarify. Thanks, kumar Please do not print this email unless it is absolutely necessary. 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 proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com<http://www.wipro.com> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu<mailto:Sip-implementors@lists.cs.columbia.edu> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors -- Vivek Talwar GlobalLogic Inc. | Innovation by Design ARGENTINA | CHILE | CHINA | INDIA | ISRAEL | UKRAINE | UK | USA Office: +91-120-434-2000 x 3217 | Mobile: +919015330797 www.globallogic.com<http://www.globallogic.com> http://www.globallogic.com/email_disclaimer.txt Please do not print this email unless it is absolutely necessary. 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 proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
