You can check the origin line of the SDP. If the origin line has not changed, the SDP has not changed. I agree it isn't very efficient; however you should not need to fully parse the SDP to perform the check. However sending a re-INVITE with a non changed SDP isn't just to refresh the session, the receiver still needs to check other headers to ensure nothing else is potentially changing.
If UPDATE is supported by both devices, sending the UPDATE request is more efficient than sending a re-INVITE for a session refresh. The mechanism uses less messages and the SDP is not needed. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of Sumin Seo > Sent: Thursday, April 13, 2006 10:53 PM > To: [email protected] > Subject: [Sip-implementors] re-INVITE > > > Hi, > > > > If during a call, UAC sends re-INVITE to change the media and > to refresh session, how can we know re-INVITE for session > refreshment from re-INVITE for media change? > > If we can know the purpose of re-INVITE only by checking > SDP, I think that is very inefficient way because in worst > case, we should check every SDP of re-INVITEs for session > refreshment unnecessarily although we never get re-INVITE for > media change during a dialog. > > > > Thanks in advance for your help. > > Sumin. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
