Patent ID: 6965946

Claim:
A relay device for relaying communication data in a communication network system formed by a plurality of computers for communicating data with each other through a plurality of interconnected networks, said plurality of computers including at least one mobile computer for communicating data while changing a location in the communication network system, the relay device being provided in a home network of the mobile computer and comprising: management means for managing an address information for the mobile computer within own organization networks of the mobile computer, the address information containing a corresponding set of a first location identifier, a second location identifier and a third location identifier, the first location identifier being a location identifier specific to the mobile computer which is uniquely defined within the own organization networks, the second location identifier being a location identifier reserved for the mobile computer which is uniquely defined over all the networks, and the third location identifier being a location identifier indicating a current visited location of the mobile computer in the communication network system which is uniquely defined over all the networks; processing means for obtaining the third location identifier corresponding to the first location identifier or the second location identifier of a destination computer attached to communication data transmitted from a source computer according to the address information, and transferring the communication data by attaching the obtained third location identifier to the destination computer; and means for managing a plurality of location identifiers reserved for mobile computers belonging to the own organization networks, and assigning one of said plurality of location identifiers as the second location identifier to each mobile computer which is moving out to an external other organization network.