Hi Salil, PRACK can contain SDP in certain scenarios. You can look at "The Offer/Answer Model and PRACK" section of RFC 3262. As per RFC 3262:
" If the UAC receives a reliable provisional response with an offer (this would occur if the UAC sent an INVITE without an offer, in which case the first reliable provisional response will contain the offer), it MUST generate an answer in the PRACK. If the UAC receives a reliable provisional response with an answer, it MAY generate an additional offer in the PRACK. If the UAS receives a PRACK with an offer, it MUST place the answer in the 2xx to the PRACK." Thanks and Regards, Rajat Chandna ________________________________________ From: [email protected] [[email protected]] On Behalf Of Verma, Salil (NSN - IN/Gurgaon) [[email protected]] Sent: Monday, September 05, 2011 9:45 AM To: [email protected] Subject: [Sip-implementors] PRACK Message HI Experts , Do PRACK Msg contain SDP information . as per Standard theory PRACK is only acknowledgement. But in my case I can see that Prack is coming with SDP . Kindly suggest what can be the reason. Thanks, Best Regards sAlil veRmA _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors =============================================================================== Please refer to http://www.aricent.com/legal/email_disclaimer.html for important disclosures regarding this electronic communication. =============================================================================== _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
