If o-line of SDP has changed then it's for the session update. If the o-line has not changed in the re-INVITE since last session update then it's for the session timer re-INVITE.
-----Original Message----- From: Christer Holmberg (JO/LMF) [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 26, 2004 2:31 AM To: 'Brett Tate'; 'Christina Zhao'; [EMAIL PROTECTED] Subject: RE: [Sip-implementors] How to determine a Session Refresh Request (re-INVITE)? Hi, You can indicate if any SDP information has been updated using the sess-version part of the SDP origin (o- line) parameter. It must be incremented if the SDP information has been updated. Regards, Christer Holmberg Ericsson Finland > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of > Brett Tate > Sent: 26. lokakuuta 2004 1:44 > To: 'Christina Zhao'; [EMAIL PROTECTED] > Subject: RE: [Sip-implementors] How to determine a Session Refresh > Request(re-INVITE)? > > > > Hi, I have another question regarding Session Timer: > > > > If the refresher is uac, how can the uas > > determine the re-INVITE is for the purpose of > > session refresh? (assuming uas needs to tell > > the difference between a Session Refresh > > re-INVITE and other purpose re-INVITEs so > > that it can pursue different process. ) > > > > There could be re-INVITEs that are Target > > Refresh Request (RFC3261 12.2), and > > re-INVITEs that change SDP. > > > > My idea is to determine by checking if the > > header part contains "Supported: timer", but > > I am not sure this condition is good enough. > > SIP currently does not provide a very complete mechanism to > communicate what > is trying to updated by a re-INVITE/UPDATE or what was > successfully updated. > The receiver basically has to analyze the request for every > header/body that > it willing to allow to be updated; and basically nothing > should be updated > if a failure response is returned. The following thread > provides a little > detail concerning the issue. > > http://www1.ietf.org/mail-archive/web/sip/current/msg08077.html > > Concerning your specific question, the RFC indicates that the > origin line of > the SDP is used to indicate when the SDP changes. However a > request to > update headers (Contact, Session-Expires, etcetera) and the > SDP can occur at > the same time. > > > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors > _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors NOTE: This message, including any attachments, may include privileged, confidential and/or inside information. Any distribution or use of this communication by anyone other than the intended recipient(s) is strictly prohibited and may be unlawful. If you are not the intended recipient, please notify the sender by replying to this message and then delete it from your system. Thank you. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
