This seems to be a problem in the spec. A 422 is backward incompatible in a sense that the UA1 will drop the dialog/session, and the session timer draft, even though mentioning in several places that the stateful proxy must "remember" what it is doing, does not catch this particular case:
The proxy does look at the supported header, so if the request did not contain either the supported header (containing "timer") or any of the session timer headers, then it should not insert any of its own session timer headers. This kind of a sitiuation, when the UAC does not support the session timer, but the proxy requires it, is easily handled in a B2B UA, which acts as a UAS on the other side. ----- Original Message ----- From: "Sani Tripathy" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, July 25, 2002 12:56 PM Subject: [Sip-implementors] UA receives 422 when it does not support Session Timer > > If the UA1 does not support session timer and initiates invite without > supported header. Proxy adds Session-expiry header to it and forwards to > UA2. > > If session-expires value is below the UA2 Min-SE, the UA2 will send a 422 > which may not be interpreted correctly by the UA1 since it does not support > Session Timer. > What will be the behaviour in this case? > Who should change the SE value? > > Sani > > _______________________________________________ > 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
