Hi Juha,
Let me provide a real example.
A SIP provider has interconnect from incumbent PSTN operator (Cisco gateway) using SIP (SER installation). This provider has an E164 number range placed in ENUM. The problem here is that when an ENUM number is resolved to a remote domain and the destination username is an alias on the remote domain, the provider proxy will pass the redirect back to gateway who in term makes the final call.
This provider gets paid by the incumbent for terminating minutes on IP for those E164 numbers but as the proxy is not in the middle they do not know how much traffic their numbers generated for anything that is an alias. The problem in this case is accounting. The Proxy should stay in the middle of the dialog in this scenario so your function makes perfect sense.
The provider receiving the calls has no way to account for the calls if it provxy the redirect.
This scenario is described very nice in Cisco SIP flows documents.
On Jun 14, 2004, at 6:34 AM, Juha Heinanen wrote:
Adrian Georgescu writes:
I would like SER to use the Contact from a Call redirected (30X) and proxy to final destination.
i once wrote a new function that could be called from failure route and that replaced request uri of invite by contact uri from 3xx. i never committed it, however, because it needed a tm hack that allowed access in failure route to the contact header then i started to think that it is not a good idea in general for the proxy to intercept 3xx replies, since it is up to the original caller to make the decision regarding the new destination.
-- juha