[OpenSIPS-Users] Use b2b modules to create ALG?

[Jeff Pyle]

One of my ultimate goals with Opensips has been to be able to configure it
to be a LAN-to-WAN ALG, handling the signaling and media transparently on
behalf of the LAN-side clients and the WAN-side softswitch.

The ALG needs to look like, for all intents and purposes, the softswitch
to the LAN clients.  And it needs to look like a client to the WAN-side
softswitch.  This means clients will register to the LAN side IP address
of Opensips.  Opensips should relay the request through to the softswitch
after updating some header information, including the Contact field to
include its own WAN IP address.  This way the softswitch will send
requests for the clients back to Opensips, that will then relay them (or
otherwise route them) to the clients.  Opensips would also need to save at
least the LAN-side IP and the username of a registration if the softswitch
replied with a 200 OK.

There's a lot in here that isn't compatible with a proxy model.  I'm
wondering if this is suited for a custom B2B scenario.  Basically, it's a
top-hiding model with some extra routing capabilities based on the
REGISTERs it passes, and the data it saves upon a successful registration.

rtpproxy would handle the media.  Hopefully no sweat there.

Am I on to something, or should I keep dreaming?



- Jeff