Patent ID: 7822034

Claim:
A path control apparatus that controls a communication path by relaying a frame including a transmission-source address and a transmission-destination address, the path control apparatus comprising: a receiving unit that includes a plurality of ports, and receives the frame from any one of the ports; a storage unit that stores therein a management table that includes a correspondence relation between the transmission-source address of the frame and a port through which the frame is received in each entry, and a generation-management bit string for each entry including a plurality of generation bits indicating a plurality of generations, wherein one of the generation bits for an entry corresponds to a time elapsed since the entry was updated and is set as an indicator bit for the entry; a determining unit that determines whether there is an entry to which the correspondence relation for the transmission-source address of the received frame can be registered; a selecting unit that, when the determining unit determines that there is no entry to which the correspondence relation can be registered, detects an indicator bit located at a position indicating a longest time elapsed in a bit string that is obtained by coupling the generation bits for all entries by the generations, and selects an entry corresponding to the detected indicator bit as an overwriting target entry to be overwritten; and an updating unit that registers the correspondence relation between the transmission-source address of the frame and the port through which the frame is received to the selected overwriting target entry in the management table in the storage unit, and changes a position of the indicator bit in the generation-management bit strings of the selected overwriting target entry to a generation bit of a generation indicating a shortest time elapsed.