Patent ID: 6473411
Filing Date: 2002-10-29
Classification: H04L,H04Q,H04W

Abstract:
A router device, comprising:at least one first interface connected with a plurality of radio base stations, each radio base station being capable of accommodating at least one mobile terminal; at least one second interface connected with a network; an information exchanging unit configured to exchange a routing protocol on a network layer, through the second interface; a memory unit configured to store information regarding a routing on the network layer based on the routing protocol exchanged by the information exchanging unit; a transfer unit configured to transfer datagram through the first interface according to the information regarding the routing on the network layer stored in the memory unit; a moving detection unit configured to detect a moving of the mobile terminal among the radio base stations; an information updating unit configured to update the information regarding the routing on the network layer stored in the memory unit when the moving of the mobile terminal is detected by the moving detection unit; and a switching unit configured to switch transmission of the datagram by the transfer unit between datagram transmission to a radio base station of a visited site of the mobile terminal and datagram transmission to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal; wherein when the datagram transmission to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal is to be used, the information updating unit updates the information regarding the routing on the network layer such that the datagram destined to the mobile terminal is transmitted to both a radio base station of an originally located site of the mobile terminal and a radio base station of a visited site of the mobile terminal.