A method and corresponding apparatus are provided to route a call from a customer to a destination. A call setup message sent from a customer switch intended to signal a switch to perform a call routing function or request a call routing function be performed is intercepted. A call release message sent from the switch intended to signal the customer switch of network congestion is intercepted. In response to either the call setup message or the call release message being intercepted, a routing engine is queried with the destination of the call for a specific route over which to carry the call. The call setup message is modified to include the specific route. The call release message is responded to with a re-route call message that includes the specific route. The switch is directed with either the modified call setup message or re-route call message to use the specific route to carry the call from the customer to the destination.