Patent ID: 7668159
Filing Date: 2010-02-23
Classification: H04L

Abstract:
1. A method for use in processing calls in a network environment which includes a circuit-switched (CS) network and an Internet Protocol (IP) multimedia subsystem (IMS) network, the method comprising the acts of: sending a SIP message from a mobile communication device to the IMS network; receiving a SIP 200 OK message from the IMS network in response to sending the SIP message to the IMS network, the SIP 200 OK message having data comprising one of at least one variable call parameter and a network address at which to obtain the at least one variable call parameter, wherein the at least one variable call parameter includes a routable number that terminates to a network node disposed in the IMS network; utilizing the at least one variable call parameter in processing of a CS call; if the mobile communication device fails to have the routable number assigned to said mobile communication device for the CS calls after registration: sending a SIP re-Register message to the IMS network; and receiving a SIP 200 OK message from the IMS network in response to sending the SIP re-Register message to the IMS network, the SIP 200 OK message having the routable number in a P-Preferred-Identity header field of the SIP 200 OK message.