Patent ID: 6904025

Claim:
A method of keeping a session active and connected with a mobile device while changing data communications networks, from a first data communication network to a second data communication network, comprising the steps of: receiving all packets, associated with a session, over a first connection in said first data communications network wherein said first connection is handled by a first gateway associated with said first data communications network regardless of whether said mobile device is located within said first or second data communication network; requesting a second connection with a second data communications network while said mobile device is moving towards the second data communication network; determining that said mobile device is in said second data communication network: initiating a transition to said second data communication network by sending a Packet Data Protocol context request towards said first data communication network, said context request including an address of said first gateway provide by said mobile device and if said first gateway address is not present in the context request, retrieving said first gateway address from a Home Location Register (HLR) of said first data communication network; acquiring an address of a second gateway associated with the second data communications network and assigned to handle said second connection; establishing a tunnel between said first gateway associated with the first data communications network serving said first connection and said second gateway; routing said packets associated with said session and received by said first gateway over said established tunnel to said second gateway and over the second connection based on the acquired gateway address to said mobile device.