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