Patent ID: 7860114
Filing Date: 2010-12-28
Classification: H04L,H04M

Abstract:
1. A method for routing calls to a destination gateway to establish a communication session call in a telecommunications network between a source user agent and a destination user agent over a path supported at least in part by a telephone network and an IP network, the IP network including a plurality of ingress and destination gateways, at least one proxy server, and at least one redirect server (RS), the method comprising: receiving a call setup request at the at least one proxy server from the source user agent, where the source user agent is included in a public switched telephone network and the call set up request identifies the destination user agent; forwarding the received call setup request to the redirect server; determining, by the redirect server, a status of a group of destination gateways in response to receiving the forwarded call setup request, where the status of a particular destination gateway is determined as one of in-service or out-of-service; adding the particular destination gateway to a routine list and recording the particular destination gateway as in-service, if the status of the particular destination gateway is determined to be out-of-service and if a time value associated with the determined status is less than or equal to a current time value associated with the redirect server; not adding the particular destination gateway to the routing list, if the status of the particular destination gateway is determined to be out-of-service and if the time value associated with the determined status is greater than the current time value associated with the redirect server; receiving the routing list or a request failure response from the redirect server; proxying the call setup request by the at least one proxy server to a destination gateway selected from the routing list upon receiving the routing list from the redirect server, where the selected destination gateway is to communicate with a public switched telephone network that includes the destination user agent; upon proxying the call setup request to the selected destination gateway, waiting for a response from the selected destination gateway; upon receiving the response from the selected destination gateway within a predetermined time, establishing a communication, session using the selected destination gateway; and if the response is not received within the predetermined time, sending the call setup request to a succeeding destination gateway selected from the routing list and reporting failure of the selected destination gateway to the redirect server, where the succeeding destination gateway is to communicate with a public switched telephone network that includes the destination user agent.