Patent ID: 8009614

Claim:
A mobile communications system conforming to Mobile IP comprising: a home agent having a global IP address; and a mobile node belonging to the home agent, wherein the global IP address is a home address common to a plurality of mobile nodes, the home agent comprising: an interface unit configured to route a received packet according to a transfer table that includes a correspondence among a home address of the mobile node, a care of address of the mobile node, and a communication session identification number for identifying a communication session opened by an application of the mobile node, with respect to each of the plurality of mobile nodes, wherein a transfer destination of the received packet is identified by a combination of the care of address and the communication session identification number; and a location information management unit configured to manage the transfer table, the mobile node comprising: an interface unit configured to send and receive a packet; and a detection unit configured to detect a change in at least one of the home address of the mobile node, the care of address of the mobile node and the communication session identification number, wherein the mobile node sends change information indicating the change detected by the detection unit to the home agent when the application generates a communication socket.