Patent ID: 6909711

Claim:
A route selection method for a voice communication system, which system comprises: a plurality of networks including IP networks; and a plurality of voice gateways, interconnecting said IP networks with the other networks for voice communication, said voice gateways being hierarchically divided into first voice gateways for accommodating nodes of said networks other than the IP networks, and second voice gateways for delivering information about the route selection; said method comprising the steps of: (a) controlling each of said second voice gateways to hold a route selection table indicating a correspondence between steering numbers and transport addresses for identifying routes in the IP network; (b) controlling one of said first voice gateways as an originating voice gateway to transmit a destination inquiring message, including a transport address of said originating voice gateway and a destination office number, to a predetermined one of said second voice gateways in which said destination inquiring message is collated with said route selection table thereof and is forwarded towards one of said first voice gateways as a destination voice gateway; and (c) controlling said destination voice gateway to transmit a destination determination message including a transport address of said destination voice gateway to said originating voice gateway; wherein said step (a) further includes a step of controlling one of said first voice gateways, in a predetermined case, to transmit a steering number and a transport address thereof to one of said second voice gateways, and wherein said one first voice gateway of step b) transmits said destination inquiring message to an address for said predetermined second voice gateway that is recorded in a declaration table of said one first voice gateway, said address for said predetermined second voice gateway being determined independently of the destination office number of the destination inquiring message.