Patent ID: 7236469

Claim:
A data transfer system using mobile IP, comprising: a MAC bridge having a plurality of ports to which different foreign networks (FN) are respectively connected; and a filtering data bas (DB) for the MAC bridge, wherein the MAC bridge comprises: means for storing a MAC address of a mobile host (MH) and an identifier of a port to which a foreign network (FN) is connected, in the filtering data base (DB), responsive to a MAC address registration request issued by an access point (AP) in a foreign network (FN); means for registering a relation of association of a MAC address of a terminal accommodated in a foreign network with an identifier of a port to which the foreign network (FN) is connected, in the filtering data base (DB), in the basis of an agent (FA) accommodated in each foreign network (FN); and means for referring to the filtering data base (DB) on the basis of the destination MAC address of a frame input to each port, and transferring the frame to a port on the basis of the already registered relation of association of the address with a port identifier.