Patent ID: 8315668

Claim:
A mobile communication system comprising a plurality of base stations for wirelessly communicating with mobile stations and an access gateway (AGW) connected to a core network, where a plurality of tunnels for forwarding data packets are established between each of the base stations and the AGW, the AGW comprising an access gateway unit (C-AGW) for communicating control messages with each of said plurality of base stations via an access network and a plurality of access gateway units (U-AGWs) each of which communicates data packets with said plurality of base stations via the access network, said C-AGW comprising: a first management table including a plurality of table entries, each storing an address of one of said base stations to be a first endpoint of a tunnel and an address of one of said U-AGWs to be a second endpoint of the tunnel, in association with a mobile station identifier; and a controller that returns a reply message to one of said base stations when a tunnel setup request message including a mobile station identifier is received from said one of the base stations, the reply message indicating an address of one of said U-AGWs to be the second endpoint of the tunnel, wherein, the controller searches the first management table for an objective table entry corresponding to the mobile station identifier specified in the tunnel setup request message, notifies said one of the base stations of the address of said one of said U-AGWs indicated in the objective table entry by the reply message when the objective table entry is found in the first management table, and if the objective table entry is not yet registered in the first management table, notifies said one of the base stations of an address of a particular U-AGW selected out of said plurality of U-AGWs by the reply message, wherein said C-AGW further comprises a second management table including a plurality of table entries, each of which stores in association with the identifier of the mobile station, communication quality information indicating communication quality to be ensured to the mobile station, and when said objective table entry is not yet registered in said first management table, said controller searches the second management table for communication quality information corresponding to the mobile station identifier specified in said tunnel setup request message and selects a particular U-AGW that satisfies the communication quality information out of the plurality of U-AGWs.