Patent ID: 7822865

Claim:
A method for use in a system comprising at least a cellular network and a wireless local area network, each being coupled to a packet switched data network, wherein a mobile unit communicates via the packet switched data network at a transport layer or above with a remote server system which is configured to facilitate a roam operation at least in part by managing compatibility issues associated with the mobile unit roaming between different types of networks, and for use when the remote server determines that the mobile unit lacks at least one communication protocol feature used by the wireless local area network, the method comprising: sending to the remote server system an indication that the mobile unit is in a coverage area of a wireless access point of the wireless local area network; receiving from the remote server system one or more executable software modules that are not already present in the mobile unit and which when loaded into the mobile unit operatively enable the mobile unit to implement the at least one communication protocol feature used by the wireless access point; receiving from the remote server system an indication to switch from a first connection between the mobile unit and the cellular network to a second connection between the mobile unit and the wireless local area network via the wireless access point; switching from the first connection to the second connection, in response to the indication, as part of the roam operation; establishing an application layer communication interaction between a first peer application program resident in the mobile unit and a second peer application layer program resident in a remote application server that is coupled to the packet switched data network, at least partially via the first connection, using a packet switched data transmission protocol; executing the first peer application program as a client side application program that communicates with the second peer application layer program via the application layer communication interaction; performing at least a first client-server interaction with the second peer application layer program prior to the switching by interacting with a protocol stack in the mobile unit; performing at least a second client-server interaction with the second peer application layer program after the switching by interacting with the protocol stack; and implementing the switching, at least in part, by switching at least one portion of a lower layer of the protocol stack from a cellular network air interface protocol software to a wireless local area network air interface protocol software; wherein the client side 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 client side application program.