I think you have answered your own question very well with excellent references (it nicely saves everyone else's time!).
:-) (UAS is not allowed to increase the SE) Regards, Attila -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Harsha. R Sent: 16 January 2008 14:41 To: sip-implementors@lists.cs.columbia.edu Subject: [Sip-implementors] SESSION REFRESH: Can SE value be increased byUAS? Hi, Consider the following scenario with regard to session-refresh INVITE[Min SE:900, (SE:900,refresher=uas),k:timer] UAC--------------------------------------------------------------------- ------------>UAS 183 SP,PRACK(183),200OK PRACK,180 Ringing, PRACK(180),200 OK PRACK follow 200 OK[(SE:1800,refresher=uas), k:timer] UAC<-------------------------------------------------------------------- -------------UAS Because the refresher is UAS, can UAS increase the value of Session-Expires value in 200 OK to the INVITE? My understanding of RFC 4028 is as follows. 1. In any negotiation of the session-refresh interval, MinSE is the lower bound and SE is the upper bound. 2. UAS MUST NOT increase the value of SE, however it can decrease it. The above points are also clearly documented in the RFC 4028, Section 9 and I quote " If the UAS wishes to accept the request, it copies the value of the Session-Expires header field from the request into the 2xx response. The UAS response MAY reduce its value but MUST NOT set it to a duration lower than the value in the Min-SE header field in the request, if it is present; otherwise the UAS MAY reduce its value but MUST NOT set it to a duration lower than 90 seconds. The UAS MUST NOT increase the value of the Session-Expires header field." Now my question is, since UAC has clearly set the MinSE(900) and SE(900) values in the Session-Refresh request and chosen UAS as the refresher in the process, is UAS allowed the latitude to INCREASE the value of Session Expires header to 1800 in the response to Session-Refresh request? -- Regards Harsha _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
