Patent ID: 9281996
Filing Date: 2016-03-08
CPC Classification: H04L,H04M,H04Q

Claim Text:
1. A method for routing calls to a destination gateway to establish a communication session call in a telecommunications network over a path supported at least in part by a circuit-switched telephone network and an IP network, said IP network including a plurality of ingress and destination gateways, at least one proxy server, and at least one redirect server (RS), said method comprising: receiving a call setup request at the at least one proxy server from a source user agent; counting a quantity of received requests subsequent to the call setup request at the at least one proxy server; forwarding the received call setup request to the redirect server to obtain routing information; responding to the forwarded call setup request received at the redirect server by determining a status of each of a plurality of destination gateways, the status being one of in-service or out-of-service, and returning said routing information comprising a list of destination gateways corresponding to ones of the destination gateways that are determined to be in-service or a request failure response; proxying the call setup request by the at least one proxy server to a destination gateway selected from said list of destination gateways upon receiving the routing information from the redirect server; upon proxying the call setup request by the at least one proxy server to the selected destination gateway, waiting for a response at the at least one proxy server from the selected destination gateway; upon said at least one proxy server receiving the response from the selected destination gateway within a predetermined time, establishing a communication session using said selected destination gateway; recording the selected destination gateway status as unavailable if the response from said selected destination gateway is not received within the predetermined time; recording the selected destination gateway status as unavailable if the response from said selected destination gateway indicates that the selected destination gateway is unavailable, where said steps of recording said selected destination gateway status as unavailable includes: if the response is not received within the predetermined time or if the response indicates that the selected destination gateway is unavailable, sending the call setup request other another destination gateway selected from the routing information.