Patent ID: 7123599

Claim:
A mobile communication system comprising: a mobile terminal having means for receiving radio waves from a plurality of base stations; a home network to which the mobile terminal belongs; a plurality of subnetworks to which the terminal might move; advertising routers respectively provided in the subnetworks to advertise information of a pertinent subnetwork to the mobile terminal; and a home agent device having means for managing location information of the mobile terminal and registering a routing address to be used temporarily in a subnetwork to which the mobile terminal moves, and means responsive to a movement of the mobile terminal when the routing address is already registered, for capturing a packet addressed to a home address of the mobile terminal in the home network and transferring the captured packet to the subnetwork to which the mobile terminal moves in accordance with the registered routing address, wherein each of said advertising routers comprises means for advertising an interface ID and a prefix section of the routing address from a base station as pertinent subnetwork information, and wherein said mobile terminal comprises a registration unit, and if the terminal has received a plurality of routing addresses having same prefix section and differing in interface ID from the plurality of base stations while moving from the home network to a different subnetwork, then the registration unit combines the plurality of routing addresses into one recognizable routing header address in accordance with a predetermined rule, and registers the routing header address with the home agent device.