No Loss Least Cost Routing
Even using a least cost routing system, it is possible to lose money on a route, either due to mis-routed calls or a too-small routing table.
Incorrect Call Routing
Calls can be misrouted for many reasons. Often, the problem is simply that a phone number has been ported to a different carrier. A routing system that does not take into account number portability, will route the call to the least cost route for the old carrier, which is often not the least cost route for the new carrier.
Routing Table Size
Some routing tables, especially those that are stored at the switch, rather than a routing server, cannot hold enough translations to assure that every route is profitable. If a routing table only stores a few translations per route, a provider might be missing out on the lowest cost route.
Today, many carriers look for a routing solution that offers no loss least cost routing. Also known as loss-less least cost routing, these systems can send alarms or block calls that will result in a loss of profits.