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
