From: "Elwell, John" <[EMAIL PROTECTED]> An interesting draft addressing a known problem space. Dan Wing has already pointed out similarities with draft-wing-sip-e164-rrc (now expired). I fear the present draft will not work in the presence of B2BUAs along the path of the INVITE request, since these tend to change things like call-ID, to-tag and from-tag. Since B2BUAs, and SBCs in particular, are the main reasons why RFC 4474 will not work, any solution has to be able to work through these devices.
However... If we change the sequence of operations a bit, so that the UAS sends a 183 with a Contact carrying a specific header parameter carrying a crypto-random value, and we get B2BUAs to pass it through (attaching it to the Contact they use in the 183 they emit on the other side), then if the UAS does a non-filtered dialog event SUBSCRIBE, it can check the returned NOTIFY to see if it carries the Contact header parameter that it created. That's a reasonably good test that the UAC of the INVITE can be reached via the From value that the UAS received. Dale _______________________________________________ Sip mailing list https://www.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
