I'm working on cleaning up a mitel system that I inheritted from a guy who didn't seem to care much about his job.
We've got 3 3300's, call them A, B, and C.
The call center consoles are attached to A.
A and B are clustered.
C has hospitality enabled, and is not clustered. Technically there's a console attached, but it's only for setting wake-up calls.
Right now we have 4 PRI trunks, and 6 LS.
For the PRI's, A has 2. B and C each have one, and there are no routes in place to share between A, B and C. A does run out of lines once in a while, B less often, and C almost never. The circumstances that would make one or another run out of lines are all very different, so all three running out at once is unlikely to ever happen.
All 6 of the LS trunks are connected to C, but they're not actually configured. The inbound numbers for those lines are unpublished, and there are no routes that use them. Looking through the ARS, you can see that they may have been configured as 2nd-choice routes in the past, but no calls have touched them for years.
What I'd like to know is what the best method would be to make proper use of all of our trunks, and provide the best total service quality and redundancy. Ideally, I'm thinking that the best option would be to move those 6 LS trunks around so that each PBX has 2. Then use route lists like the following:
A
1st choice PRI group on A
2nd choice route to B
3rd choice route to C
4th choice LS on A, COS restrictricted so only A can use it.
B
1s choicet PRI group on B
2nd choice route to C
3rd choice route to A
4th choice LS on B, COS restrictricted so only B can use it.
C
1st choice PRI group on C
2nd choice route to A
3rd choice route to B
4th choice LS on C, COS restrictricted so only C can use it.
If I build that out right, it should put all the PRI's into a single pool of 92 lines, while still keeping lines to the outside world, even if 2 PBXs go offline. If the PRIs all went down but left the LS trunks up, each PBX would keep 2 lines open for outbound calling.
That brings the questions:
1. Is this even a sane idea, or is there a clear reason why this wouldn't be a good idea?
2. How to I do this without creating a loop? Alternatively, do I care if this creates a loop?
3. Is there a better way to accomplish this?