[Asterisk-Users] * and Verisign SIP-7 service

[Stewart Nelson]

>> Can you expand ... I'm hoping to use Asterisk to do SIP to MGCP 
>> mediation ... what does it not work?

> I don't know the particulars, because I've never used (or even looked at 
> MGCP). All I know is that whenever the issue comes up, people here say 
> that Asterisk does not know how to act as an MGCP Gatekeeper, only as an 
> agent. I presume it would have to act as a gatekeeper to control an 
> MGCP-based media gateway, because those devices are all intended to be 
> controlled by some sort of softswitch.

IMO, there is no such thing as an "MGCP gatekeeper"; try that phrase
with Google and it will be obvious.  "Gatekeeper" is an H.323 term.

MCGP is a master-slave protocol.  The master is referred to as a
"Call Agent", a "Media Gateway Controller", or just a "softswitch".
This is the role that Asterisk can play.  The slave is a "Media
Gateway", an "MGCP phone", an "MGCP ATA", or just an "endpoint".
Asterisk cannot presently act as a slave.

Of course, any large system may have higher-level elements that
handle authorization, accounting, complex routing, queueing, etc.,
but those topics are beyond the scope of MGCP.  Perhaps the
term "gatekeeper" was used in that context.

So, I think that Asterisk will provide the functionality that you
desire.  However, I don't know if SIP<->MGCP calls can presently
be completed without Asterisk proxying the media stream, so you
may have performance issues.  Perhaps someone else can address
that.

--Stewart