Enhanced call routing in competitive local telephone networks

摘要

A telephone network includes an Enhanced Call Routing (ECR) function that reroutes calls when the high usage route and fixed tandem routes are overloaded or otherwise unavailable. The ECR function tracks the operation of the telephone network on the basis of origination switches and destination switches and provides temporary network rerouting during outages and unusual loading situations. Further, the ECR function supports Local Number Portability (LNP) so that it may operate in those telephone networks that are designed and/or modified to support LNP. The ECR function resides on a signaling network element such as a Service Switching Point (SSP) and/or a Service Control Point (SCP). A call setup request is received by a Service Switching Point (SSP), an origination switch in the traffic network, and intended for a destination switch. Initial routing via a high usage route and fixed tandem route(s) are unsuccessful. The SSP sends a Network_Busy message to the STP/SCP supporting the ECR function. The ECR function then attempts to determine an alternate tandem route for the call. If successful, the ECR function directs the SSP to route the call along the alternate tandem route, the alternate tandem route either being via the telephone network or via an alternate telephone network coupled thereto. If not successful, the ECR directs the SSP to send the call to a resource for caller notification. In another operation, the ECR function monitors the number of Network_Busy messages received for each originating switch/destination switch pair in the telephone network.