[Asterisk-Users] Re: Multi-office topology suggestions

[David Cook]

> We have five offices in Canada. Our main office is in Edmonton , with
> branch offices all over the nation. I would like to place the
> Asterisk
> server in the Edmonton office and have it route calls to the branch
> offices. I would also like to have each of the branch offices have a
> local phone number. That local phone # would actually dial into the
> Asterisk box , and then routed appropriately via VPN to the correct
> location. This gives us a method of controlling and tracking all
> calls
> made to all offices.

Several ways to skin that cat.

If you prefer/need one switch, then you will probably want remote FXO in
the smaller offices. Something like a Sipura SPA-3000 at the low end or
moving up to some of the larger multi-fxo devices that are out there.
This will put a huge importance on the quality/availability of your
data circuits and provider. In Canada you have Telus in the west, Bell
in central and Alliant on the coast. Allstream is smaller but
nation-wide and concentrates on business. Depending on where you are
(on-net/off-net) you will likely be in a wholesale market at one
location or the other and this will by definition hurt your Mean Time
To Repair (MTTR).

Or you can have an asterisk server at each location and combine the dial
plan. Depending on your calling patterns, you probably want to write
some custome Least Cost Routing code (agi can work for this) to
determine if it's better to trunk the call from A to B and pickup PSTN
from there, or just call PSTN from your local site.
You might want to have the same voice menu at each location for
availability rather than have everything trunk back to one. That way,
you wouldn't lose your menus if you had a network outage. You will also
want to ensure the LCR code accomodates dead IP paths and automatically
routes over PSTN to get there seamlessly to employees & customers.
(Inbound call from site A to site B is recognized by ANI and behaves
like it was an internal call trunked over IP, etc.)

This way your employee sat and customer experience don't change and you
just modify your phone bills dependant on how good your data providers
are.

dbc.