[asterisk-users] Role of asterisk

[Jared Smith]

On Wed, 2008-11-19 at 12:33 +0200, Valentin Bud wrote:
>  When you have an asterisk box connected between the VoIP
> phones and an PSTN gateway what is the role of asterisk. Proxy server:
> stateful or stateless?

Close, but not quite.  Actually, Asterisk is what we call a back-to-back
user agent.  The most basic difference between a proxy and a
back-to-back user agent is that with a proxy, a single call gets passed
*through* the proxy and on to the destination.  The proxy is not the
destination of the call.  With a back-to-back user agent, Asterisk is
the destination of one call (in this case, the VoIP call), and then it
creates a whole new call on the other side (to the PSTN in this case).
It then acts as an endpoint to both calls, and sits in the middle and
bridges the two calls, all while doing any necessary protocol or codec
conversion between the two calls.

Make sense?


-- 
Jared Smith
Training Manager
Digium, Inc.