Patent ID: 8837432

Claim:
A method for a mobile node to register with a home agent on a home network, the method comprising: registering with the home agent to establish a first Internet protocol (IP) tunnel between the home agent and a first foreign agent on a first foreign network; after the registering, detecting entry into a buffer zone that includes (1) a portion of the first foreign network that extends into a second foreign network and (2) a portion of the second foreign network that extends into the first foreign network, the second foreign network being served by a second foreign agent; in response to the detected entry, registering with the home agent to establish a second IP tunnel between the home agent and the second foreign agent; and while located inside the buffer zone, discarding datagrams from one of the first IP tunnel and the second IP tunnel and accepting datagrams from the home agent via the other of the first IP tunnel and the second IP tunnel.