[Serusers] Asterisk SER Integration

[Terry Wilson]

We are trying to use SER as a NAT traversal solution in front of our
Asterisk PSTN gateways and our Asterisk Feature Server.  Currently,
the feature server is doing all of the dialplan processing.  Because
of this we can have user configurable dial times, unavailability
numbers, forward on busy/unavailable numbers, auto-attendants, 7-digit
dialing, etc.

Of course, my life would be simple if Asterisk acted more like a SIP
proxy server and the dialplan could be executed somewhat like an SER
routing script.  Unfortunately, any call that comes from a UA to
asterisk creates one call, then asterisk creates another call to the
other end of the conversation (other SIP device, PSTN number,
whatever), then issues reinvites to the two ends of the conversation
to tell them to send RTP to each other.

So what I need, is an SER script that will intelligently handle NAT
traversal for UA to UA calls, UA to PSTN calls, and PSTN to UA calls
(all going through the Asterisk Dialplan so we can keep all of the end
user features) including the damn re-invites.  Anybody had to do this
before?  We are quite willing to pay you for your knowledge if you
want to do some design/consulting/coding work for a solution to our
problem.

Thanks.