IVM is designed to operate as almost a server application. Typically it runs on a dedicated computer and all other programs that need to use it (e.g. Express Talk) on different computers connect to it via the local area network. I wouldn't recommend having multiple installations of IVM on different computers for several reasons:
- You would have to purchase new licenses for each computer you wanted to run it on (which will get quite costly)
- Maintenance of the system will be much more difficult, and if you need to change how one program operates, then you'd need to go to each one individually and change it (although IVM has some sort of auto-update feature that looks for new config files in a network location, I've heard it is a bit buggy but personally haven't tested it)
- The cost of having several high performance computers available to basically just run IVM wouldn't be feasible, and if you did use them for other uses (such as web browsing) you risk causing quality loss and/or disruptions to any phone conversations.
Also my other concern is when you say each computer gets an individual 256kbps line... usually what happens is a business will have one 256 kbps line and they use an intelligent switch which can split the internet connection up for several computers without seeming as though there is any lost bandwidth. When it comes down to technicalities, no matter how fast the switch can "switch" you can't make bandwidth from nothing, and it'd be impossible to guarantee each computer 256kbps of bandwidth.
If your business truly has for example 10 completely standalone internet connections for each computer (which frankly I cannot see happening, I've certainly not heard of businesses doing this, and it'd be much cheaper and easier if the computers were all on a shared LAN network and could access one internet connection. But anyway, assuming this is the case, you will have problems getting all your extensions communicating to each other because you won't be on the same LAN, and this just adds new layers of difficulties and unnecessarily complicates things.