[asterisk-users] Feasibility Request

[Andrew Kohlsmith]

On Tuesday 15 May 2007 3:31 pm, Jeremy Mann wrote:
> 1.        Is it feasible to use asterisk as a Man in the Middle for a T1
> PRI system?  The idea is to intercept outbound calls from the Nortel PBX
> and redirect them via VoIP to another asterisk box at another branch
> transparently(thus saving the LD cost).  Otherwise I'd pass the call on to
> the T1 for outbound processing.  Our Nortel is already PRI equipped, the
> PRI would just come from the Asterisk box instead of the Telco directly.

I am doing this right now with our MICS.  Asterisk is the telco, and routes 
the calls over our PRI or VOIP provider.  I also do a little bit of external 
extensions.  While it works, it's hokey.

> 2.       Is it feasible to use asterisk as a Man in the Middle for Analog
> lines?  I'd be using anywhere from 4-12 lines depending on location size. 
> I'd like to do the same feature as above(intercept outbound calls and
> redirect them using VoIP if they are inter-office calls.

Yes, I was doing this before the PRI.  Make sure you're using the right 
channel bank for FXO, or you won't get CPD.

> a.       I'd also like the VoIP trunks to be used for outbound calls in the
> case of PSTN downtime or busy.  For example, all 4 outgoing lines are in
> use, person 5 wants to make an outbound call and it gets redirected to one
> of my T1 offices.  I'd attach their outbound caller ID to make it appear as
> the call came from that location. My inevitable hope is to reduce my analog
> presense in smaller communities to 1 primary Line for 911/emergency
> calling, and to get a published presense in the community.  I'd then beef
> up my T1 locations to handle more VoIP based calls.  Currently we're using
> on the order of 30k minutes a month of LD just intercompany, about 10k
> external (IntraLATA).

Piece of cake, it's just LCR and failover.  With the right dialplan nobody 
knows whether the call went over VOIP or local PSTN.

> I'd also like any insight or suggestions on uptime.  We're a healthcare
> organization so 5-9's is what we'll require.

If you want 5 nines out of Asterisk, you're looking at a failover system with 
a database backend, and T1 failover to the Asterisk boxes.  Now you'll also 
need redundant power and really look at the entire system to make sure there 
aren't any single points of failure that aren't five nines themselves (i.e. 
you won't need two PRIs, as they're already considered five nines).

Honestly though... take a look at the Citel gateways.  Plug all of your 
Norstar phones into that and connect it to Asterisk.  There's your PBX.

> Any suggestions on hardware configs(or better yet, Bids!) would be
> appreciated as well.  I don't need VoIP capable phones yet, but if the
> system works well enough we'd probably startup our next location(averaging
> 3-6 per quarter) with a pure VoIP system with Nortel fallback(again, 5-9's
> is critical).

Send me some more information offlist and I'll see what I can do for bidding.  
Honestly though you'll want to be hands-on on this, as it'll be your butt on 
the line when (not if) they fall over.

-A.