[asterisk-users] Re: New T1 Asterisk installation

[Alex Balashov]

On Mon, 16 Apr 2007, Matt Putnam said something to this effect:

> Since we are on the topic of t1/PRI i was just curious as to how people 
> running a t1/PRI card in their asterisk boxes would handle a failure. We 
> use a PRI but instead of having it run to our asterisk box we use a cisco 
> 3600 router to terminate the PRI and then sip to the asterisk box. Now a 
> failure for us is simple just change the ip on the backup box and your 
> done. Im just curious ive heard pros and cons for a t1/PRI card in the 
> asterisk box and interested to see how people deal with failures in that 
> type of setup.

   You can get T1 cards with VoIP DSP cards for a 3600 chassis?
Interesting... :)  Would you mind sending me your router config?  I'd be 
curious to see if it resembles typical Cisco MGW configurations.

   There are a lot of reasons, in my opinion, not to feed a PRI straight 
into Asterisk from the carrier if you can afford not to.  Most people do it
because they can't afford not to, since outside media gateways along those
lines can be pricey.

   But fundamentally, PCs are PCs, and their architectural reliability and 
uptime is not to be overstated for providing carrier-grade uptime.  It is 
better to offload the edge functionality to dedicated and well-engineered 
equipment that is designed for 24/7 availability.  I would avoid putting 
outside PRIs into Asterisk directly, although there may be a lot of reasons 
to do T1-based cross-connect / DACS type stuff that way, depending on the 
application.

   I imagine there may be an ample diversity of opinion on this subject, 
however.

   For large-scale environments, the best way to take care of this is to 
have a clear separation of signal/call controller vs. media conversion
functionality.  Take the TDM circuits into a media gateway, have those
calls handed off as SIP to a proxy which can intelligently hunt through
endpoints.  Throw some kind of clustering or centralised access/storage
layer into the mix and you're set.

My $.02,

-- Alex


--
Alex Balashov <sasha at presidium.org>