Patent ID: 7490172

Claim:
A method for use in a system comprising a mobile unit, a cellular network including a cellular base station, a wireless local area network, and a remote server system that is remotely coupled via an Internet to both the cellular base station and the wireless local area network, wherein the remote server system is configured to facilitate a handoff operation at least in part by managing compatibility issues associated with roaming between different types of networks, the method comprising: establishing an application layer communication between a first peer application program resident in the mobile unit and a second peer application program resident in a remote computerized device; the mobile unit receiving, at least indirectly from the remote server system, one or more executable software modules that are not already present in the mobile unit prior to the handoff operation to be loaded into the mobile unit in order to implement a communication protocol feature to enable the mobile unit to communicate using the communication protocol feature after the handoff operation; and switching a wireless Internet access connectivity of the mobile unit from the cellular network to the wireless local area network, to thereby effect the handoff operation, wherein the switching is performed at least in part, by switching at least one portion of a lower layer of a protocol stack in the mobile unit from a cellular network air interface protocol software to a wireless local area network air interface protocol software, and the wireless local area network air interface protocol software includes at least one of the one or more executable software modules; wherein the first peer application program interacts with the protocol stack at an interface point above the at least one portion of the lower layer of the protocol stack affected by the switching, so that the switching is transparent to the first peer application program, and whereby the switching is performed in a manner which results in continuity of the application layer communication before and after the handoff operation.