Patent ID: 7298720

Claim:
A packet communication system comprising packet communication devices that are arranged in a plurality of foreign networks, respectively, and that are at least part of foreign networks existing as networks visited by a mobile node, wherein when the mobile node moved among the plurality of foreign networks, if a packet communication device is arranged in a visited foreign network, the mobile node is given by the packet communication device a care-of address that corresponds to the visited foreign network in a one to one manner, the mobile node continuously sends information pertinent to an updated care-of address given in the most recently visited foreign network, after moving through at least three foreign networks, to at least one of the packet communication devices arranged in the at least three foreign networks in which the mobile node visited previously, and a packet that is sent from a corresponding node designated to the mobile node at a care-of-address given in a respective previously visited foreign network is transferred from the packet communication device of the respective previously visited foreign network directly to the updated care-of-address.