Planning a large OCS deployment with multiple pools can be tricky. Planning your dial plan can also be something of a challenge especially if your new to the world of voice and have come from a server or data background. I am not going to go through the basics but look more at future proofing a large dial plan so that adding more routes and complexity further down the track can be simplified.
Let’s start with location profiles and normalizations rules. One of the big things I have committed to with the OCS deployment I am working on, is change is for the better and things like abbreviated and regionalized dialing are things of the past with click to dial (that’s the line I take anyway). With a large voice deployment (100,000+ endpoints no matter what they are) standardization is key to simplifying configuration and keeping your TCO down. Standardizing on a ten-digit NANP dial plan inbound and outbound was key on keeping the dial plan simple in a multi region, multi PBX environment. No more abbreviated dialing per geographical region and no more access codes to get an outside line. This worked well with the idea of centralizing our deployment and keeping OCS in our datacenters. With OCS, not requiring tie trunks between pools like a typical PBX makes the job a whole lot simpler as well. See Location Profile example below (save image and enlarge to get a better look):
As you can see its pretty basic and with that in mind now we can limit our UM dial plans as well and in a centralized model it’s going to work well. Of course this isn’t the approach most voice people will take. Looking at traditional PBX model’s most old voice guys are going to stick their nose up at no abbreviated dialing for a user. Well all I can say is if you know the persons number by heart their more than likely in your buddy list anyway and you can just click to dial.
The exception to this would be special services should you require them and in a large enterprise dial 0 for operator is a pretty common one. This of course would be a simple add and better yet normalizing the 0 to a ten digit NANP to go to a local operator number even better for outbound dialing. Of course, simplicity is not for everyone and the more localized your special services the more likely you are going to need more location profiles. No one wants to dial security *77659(example only) in St Louis and talk with the security people in Redmond. So it’s something to be aware of.
If you have not already noticed 011 for international is still there. Some habits just die hard I guess. Just to reiterate the simpler you keep your dial plan the simpler it will be to do things like add new sites and pools. Making a ten-digit dial plan could be your best friend.