Least Cost Routing

Having retrieved a set of eligible carriers for a call, Least Cost Routing ensures that the call is sent to the carrier offering the cheapest termination rate for that destination. As an example, imagine that the Routing tables hold the following entries for Germany:

Digits	Route 1	Rate 1	Route 2	Rate 2	Route 3	Rate 3
49	10	0.0150	11	0.0160	12	0.0170
4930	13	0.0100	12	0.0170
4940	11	0.0140	10	0.0150	12	0.0170

If a call arrives for +49 40 9876543 (Hamburg, Germany), then a routing request will be made and the nearest match from the routing tables will be retrieved. This will return three candidate carriers for the call: 11, 10 and 12. If Least Cost Routing has been implemented, then, the call will initially be sent to carrier 11, because their termination rate (0.0140) is the lowest.

This behaviour can be overridden at a tariff or account level, in which case, and individual carrier can be chosen, or a smaller sub-set of the eligible carriers can be used.

If the first choice call to carrier 11 fails, then the call may be subject to alternative routing, in which case, the call is not cleared, but is automatically sent to the second choice carrier; in our example, this would be carrier 10. This process continues until there are no further carriers available, at which point, if the call has not been accepted by a carrier, it is cleared.

You can check the current and future routing of a particular number using the Routing Check page.