2012/7/30 Daniel-Constantin Mierla miconda@gmail.com:
There is one situation that will not work even with gruu/ob -- in sip a phone can call without registering. A gruu contact is obtained via registration and then used for next requests by UA itself. By calling without registering, there is no gruu contact for it, so adding the src ip and port as alias parameter is still needed. I don't remember I have seen any rfc making registration mandatory before calling.
Hi Daniel, RFC 5626 (Outbound) assumes that the UA registers after connecting to the (Outbound Edge) Proxy.
In other words, just to summarize the gruu versus contact aliasing.
I don't think this iw "gruu versus contact aliasing" but "outbound versus contact aliasing". Outbound means that the proxy inserts a flow token in the Record-Route username and then, when a request with Route header arrives to the proxy, its Route username is inspected and the associated connection retrieved for routing the request without inspecting the RURI (unless it's a GRUU RURI).
Regards.