Asterisk For Multiple Locations

Hi All,

I have a medical customer with nine office locations that in the Atlanta area. All locations are within local calling distance from each other. The main office has a dual T1 while the remote locations have a single T1. Each remote location supports about 4 to 8 phones while the main location supports about 15 phones. They currently use Cbeyond’s voice/data product that allows you to connect your analog PBX into their Cisco IAD. They have Merlin Magic and Avaya phone systems. They also run a couple of medical applications, Windows domain, and Exchange across this WAN environment. Each office has it’s own PBX and it’s own phone number, so the offices aren’t really integrated as it relates to their phone systems. I actually like Cbeyond’s product, but I’m wondering if they can chop their $10,000 per month data/voice bill in half by going strictly VOIP using Asterisk and also integrate the company a little better by implementing some call center type features.

  1. Will we recognize a substantial savings by transitioning to a total VOIP if all locations are within local calling distance of each other and not many long distance call are made?

  2. Will transitioning to a total Asterisk environment mean setting up Asterisk servers at each location?

  3. What size servers should I consider if the company wants to record 50% of the calls and have all the functionality of a call center.

  4. Is SDSL such as Covad’s Enterprise SDLS service ( … speed.html) just as reliable as a T1 or should I not consider doing this over any type of DSL?

Please note that applications are mission critical and organization begins losing money when network goes down (especially main office). Cbeyond rarely ever experiences problems, but it doesn’t seem to make since to do VOIP over Cbeyond’s T1s since they are already charging a premium for providing VOIP with their T1s. This is something we will phase them into slowing since their Cbeyond contracts for each location expires anywhere from 1 - 3 years. Any advice would be greatly appreciated.



  1. Not really most T1’s include unlimited local calls and with VOIP you still need data access so that would still include a T1 or DSL/Cable cost at each location.

  2. With a setup that small I would run one Asterisk server at the main office and connect the sites via VPN.

  3. Any current dual processor server, 2-4GB RAM with a raid 0 or raid 10 disk array will be more than adequate.

  4. No - T1’s are still much better for reliability. That doesn’t mean you shouldn’t use DSL though. The branch offices would be a great candidate for DSL as a cost savings. Make sure you find out what the SLA’s are on the DSL versus the T1, typically the SLA is much higher on the T1 than DSL even for DSL business accounts. This is really a judgement call.

If I were you I would shop around for cheaper T1’s we just recently switched providers, got better customer service and pay almost half what we were paying before.