Yes, obviously RFC 4474s mechanisms end at a B2BUA because the B2BUA effectively starts a new call (from the UAC side). In fact the B2BUA cannot even provide a new Identity header if the From header remains unchanged because the Contact would typically be specific to the B2BUA and the private key for senders domain is unknown to this B2BUA.
It however is not as bad as it sounds because typically B2BUAs (SBCs in particular) would be within the final UASs trust domain. Nasir -- Get the most comprehensive open source SIP testing framework at http://sipper.agnity.com -- On Tue, Oct 28, 2008 at 6:35 PM, Dean Willis <[EMAIL PROTECTED]>wrote: > Elwell, John wrote: > > > > IBC said: > >> Since the B2BUA has detailed info of both legs A and B, it is > >> capable of doing needed changes, as replacing call-id and to-tag in > >> Event header. Also, the B2BUA could handle the SUBSCRIBE by its > >> own, this is, becoming a dialog presence server instead of > >> forwarding the SUBSCRIBE to the UA. B2BUA must handle all this > >> stuff since they are, in fact, the end point, not the UA's behind > >> them. > > > > [JRE] This reduces it to transitive trust, i.e., no better than > > P-Asserted-Identity. The UA that receives the INVITE request has to > > trust its local B2BUA to confirm that the INVITE request really did > > come from the wherever it claimed to have come from. > > > > > > Since the INVITE is coming from the SBC (even though the SBC was > influenced by something else to get it to send the INVITE), I don't see > a problem with this. > > Otherwise said, SBCs are always transitive trust unless we have > end-to-end crypto, in which case we don't really have SBCs. > > So? > > -- > Dean > > _______________________________________________ > 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 > -- Get the most comprehensive open source SIP testing framework at http://sipper.agnity.com
_______________________________________________ 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
