PACKET TRANSFER APPARATUS AND PACKET TRANSFER METHOD

摘要

PROBLEM TO BE SOLVED: To improve reliability by maintaining connectivity with LNS even if switching from an active LAC to a reserve LAC occurs when performing inter-system redundancy over the LAC.SOLUTION: A packet transfer apparatus is connected to a transmitting-side client device of an active layer-2 tunneling protocol (L2TP) tunnel and a transmitting-side client device of a reserve L2TP tunnel and comprises: a table updating section which determines that the active L2TP tunnel is switched to the reserve L2TP tunnel and updates a table of correspondence between client devices and receiving-side server devices of the active and reserve L2TP tunnels; an address translating section which refers to the updated correspondence table and rewrites a transmission source address or a destination address of a packet, and a transfer processing section which transfers the packet of which the transmission source address or the destination address has been rewritten.