Quote Originally Posted by VOIPoTim View Post
No, we're actually using more carriers than we ever have before. Inventory will vary though.

Here's what could be happening.. We will not order new numbers from our carrier if we have existing numbers in a given area in our inventory. Basically if we're already paying for blocks that are unused, it doesn't make sense for us to purchase new individual numbers in that area when there are unassigned ones we're already paying for. That might be what's happening if you see a small number of numbers in a rate center (when they're used up, they'll be replenished with a new block).

In terms of cancelled numbers, we can reissue them if we still have them unassigned in our inventory, but if we've already sent the number back to the carrier we wouldn't be able to reissue it until they . Once it goes back to the carrier we have no way of reissuing it unless it's just added back into their inventory.
Years ago, in the POTS world, we had to buy numbers in blocks of 10,000....As a result, since for smaller providers many of those never got used, they were paid for but just sat there and depleted the inventory for the rest of the industry.
I think the minimum quanty of numbers in the blocks are far less these days..