Patent ID: 6990339

Claim:
A method for maintaining an active communications session between a mobile host and a correspondent host, said mobile host served by a particular one of a plurality of access networks and capable of moving into a geographical area being served by a different access network and being served by said different access network, said method comprising the steps of: assigning an identifier to said mobile host wherein said identifier is independent of said access network currently serving said mobile host; assigning a network address to said mobile host for establishing a communication session with said correspondent host wherein said network address is dependent on said access network currently serving said mobile host and changeable when said mobile host is later served by a different access network; registering data with a network database wherein said data correlates said assigned identifier with said assigned network address for said mobile host; informing said correspondent host of said identifier when an active communication session is first established between said mobile host and said correspondent host wherein said network address assigned to said mobile host is accessible by said correspondent host when said identifier is provided by said correspondent host to said network database; storing a second network address identifying said correspondent host within said mobile host, said correspondent host currently maintaining a communication session with said mobile host; detecting said network address assigned to the mobile host being changed in response to said mobile host being served by a different access network; and sending a message to said correspondent host indicating the change of said network address wherein said message is identified with said identifier.