Patent ID: 7787878

Claim:
A method for enabling number portability in a communication session between a caller and a callee when the callee moves from a terminating home network to a target home network, the method comprising: contacting a border element of the terminating home network of a first service provider by a serving node from an originating home network upon receiving a call request initiated by the caller, the call request comprising at least a first public identification number associated with the callee; obtaining a second public identification number associated with the callee and assigned by the target home network of a different service provider from a user location function module by the border element based on the first public identification number for communication session redirection; based on the second public identification number, performing a handshake between the originating home network and the target home network of the different service provider to establish a direct communication between the originating home network and the target home network of the different service provider without involving the terminating home network of the first service provider, wherein the terminating home network of the first service provider communicates one or more messages with the target home network of the different service provider, the one or more messages indicate that the terminating home network of the first service provider does not need to stay involved for communication session redirection in future communications between the caller and the callee, and wherein the terminating home network of the first service provider and the target home network of the different service provider are IMS networks.