Patent ID: 7664014

Claim:
A method of routing a session initiation protocol voice call through a plurality of gateways using a proxy server priority table, comprising: setting a proxy server priority level to a first level; contacting, by a gateway, a designated proxy server if the proxy server priority level includes a proxy server associated with a pointer value; sending the session initiation protocol voice call through the designated proxy server if the designated proxy server responds before a time out value associated with the designated proxy server; contacting a highest priority proxy server in the proxy server priority level if the proxy server priority level does not include a proxy server associated with a pointer value; sending the session initiation protocol voice call through the highest priority proxy server in the proxy server priority level when the highest priority proxy server in the proxy server priority level responds before a time out value associated with the highest priority proxy server in the first level; and setting the proxy server priority level to a second level when a next lower priority proxy server does not exist in the first level.