Patent ID: 8189510

Claim:
A mobile IP communication system comprising a home agent that manages a location of a mobile node in accordance with a location registration request and a plurality of foreign agents that are capable of accommodating a mobile node, wherein the plurality of the foreign agents comprises: a storage unit to store routing information representing a communication path to the home agent; an output control unit to detect a state of the communication path to the home agent represented by the routing information; and; a control unit to transfer a received location registration request, wherein the control unit of a first foreign agent transfers the received location registration request in accordance with routing information stored in the storage unit of the first foreign agent, when the communication path between the first foreign agent and the home agent is in a normal state, the control unit of the first foreign agent transfers the received location registration request to a second foreign agent, when the communication path between the first foreign agent and the home agent is not in the normal state, and the first foreign agent comprises: an inquiry unit to inquire other foreign agents about a state of the communication path to the home agent; and a selection unit to select the second foreign agent to be transmitted the received location registration request from the other foreign agents in accordance with a response to an inquiry by the inquiry unit.