Method and apparatus for communication control of mobile computers in communication network systems using private IP addresses

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;
• and
• 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.

A data packet processing device for processing 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 data packet processing 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;
• and
• processing means for receiving communication data transmitted from a relay device provided in the home network of the mobile computer which is encapsulated using the third location identifier corresponding to the first location identifier, then decapsulating the communication data using the third location identifier, then encapsulating the communication data using the second location identifier corresponding to the third location identifier, then encapsulating the communication data using the third location identifier, and then transmitting the communication data to an external other organization network, when the mobile computer is located within the external other organization network and the communication data has a destination specified by the first location identifier.