Hi Alfred,
There are many considerations you need to take into account when designing for a VoIP deployment. Your question is pretty vague as is your description about your situation and what you plan on deploying.
From what I can gather you have two offices which are connected by a 10Mb circuit, presumably Ethernet, and they are also connected via a Voice T1. I assume this is some sort of trunk between existing PBXs?
Are you looking to deploy a Cisco Voice Solution or are you just looking to have your PBXs trunk over VoIP as opposed to the T1?
In either case the 10Mb circuit most likely can carry your voice traffic and you could get rid of the T1, but as I stated there are many things you need to consider such as:
- How many calls do you need to support between the sites?
- What Codec will you use? (This plus the above will determine the required bandwidth)
- What will do Call Admission Control (CAC)? (To ensure you don't go above the bandwidth determine above)
- QoS Configuration, both on your side and if it's a multi-point solution on the provider side
- What happens when the connection between the offices go down, will you need SRST?
Voice is a very demanding network application and as the other poster mentioned you should seek help from professionals who specialize in this type of work.
Joe
