[asterisk-users] Feasibility Request

[David Gomillion]

On 5/15/07, Jeremy Mann <jmann at txhmg.com> wrote:
>
>  I have a ton of Nortel MICS/CICS phone systems and am looking for an easy
> way to integrate them.
>
>
>
> Two questions arise:
>
>
>
> 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.
>

Yes, I've already done it. Just make sure you use a T1 cross-over and get
the signalling correct (use pri_net instead of pri_cpe)

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.
>

I've done that too, using the same PRI as part 1.

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.
>

This isn't really a big deal. Just have a fall-through when PSTN lines are
full/down.

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).
>

You can get local presence by having a provider who can sell you a DID from
your local areas and trunk them to a PRI/T1 in another area, or deliver them
over SIP. The challenge with having only one analog line in a city means you
can't receive 2 calls at the same time... definitely sub-optimal!

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

We're healthcare too, but in Ophthalmology. So 5-9's aren't really required
here, although we've had it. I haven't really had any problems with Asterisk
reliability. In the setup you propose, you're probably going to see more
challenges in keeping your Internet connections up with good latency than a
well-built Asterisk system.

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).
>

Buy decent servers, with redundant power supplies, raid-5 arrays with a
software mirror across different array controllers, keep a warm-standby at
each location, install separate diesel generators in each location, move
your offices into underground bunkers in secret, nondescript locations, hire
armed trolls to guard the server and pummel anyone who attempts to approach,
etc.

The point is, you can have as much reliability as you're willing to buy.

I'm located in Dallas, TX for any bids that might include installation.  We
> have a presense up to about 400 miles west of here.
>

Spent a couple of years in Addison, and I grew up in Houston. But I can't
really offer too much on-location help, as I've moved to FL. Ah well, can't
win 'em all, right? But if you get the trolls, I may be willing to make the
trip ;)
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