Patent ID: 7809125

Claim:
A method of routing telecommunication calls in a communication system based on media type where the communication system has an IP network and a circuit switched network and the IP network has a plurality of gateways interconnecting the IP network to the circuit switched network with each of the plurality of gateways controlled by a one of a plurality of session initiation protocol proxies, comprising: initiating a telecommunication call by a first telecommunication terminal from the first telecommunication terminal connected to the IP network to a second telecommunication terminal connected to the circuit switched network; detecting a requirement for a special media type for the telecommunication call by the first telecommunication terminal; transmitting a message to the plurality of session initiation protocol proxies which are components of the IP network to set up the call and defining the requirement for a special media type in the message by the first telecommunication terminal wherein each of the plurality of session initiation protocol proxies is responsive to the message to determine if a one of the plurality of gateways connected to the second telecommunication terminal and controlled by a one of the plurality of session initiation protocol proxies can provide the special media type; and establishing the telecommunication call by the one of the plurality of session initiation protocol proxies controlling the one of the plurality of gateways upon the one of the plurality of session initiation protocol proxies determining in response to the message that the controlled one of the plurality of gateways can provide the special media type and interconnects the second telecommunication terminal to the IP network via the circuit switched network.