Patent ID: 8265072

Claim:
A frame switching device, to which a plurality of input ports and a plurality of output ports are connected, for deciding an output port number of an input frame inputted from the input ports from header information of the input frame and transmitting the input frame to the output port corresponding to the output port number, the frame switching device comprising: a key information supply unit that: holds a first contents addressable memory (CAM) that has entries each of which is a forwarding entry that contains a respective destination MAC address or a flow entry that contains an address corresponding to a respective source MAC address or a respective destination MAC address, holds a key information table that has a respective key information entry corresponding to each of the entries of the first CAM containing key information that respectively identifies the respective source or the respective destination MAC addresses of the corresponding entry of the first CAM and has a shorter bit length than the MAC addresses of the entries of the first CAM, manages source and destination MAC addresses for transmitting the input frame, source key information corresponding to the source MAC addresses of the input frame, and destination key information corresponding to the destination MAC addresses of the input frame, and respectively decides the source key information and the destination key information corresponding to the source MAC address and the destination MAC address in an input frame; a destination decision unit that holds a second contents addressable memory (CAM) that has entries in which each entry respectively contains key information and information other than a source MAC address and a destination MAC set in a correspondence relationship, holds a destination information table that has a respective entry for each of the entries of the second CAM that stores a destination corresponding to the entry of the second CAM, and decides an output port number for the input frame based on the destination key information decided by the key information supply unit for the input frame and the information different from the source MAC address and the destination MAC address in the input frame; and a flow decision unit that decides flow information based on at least one of the source key information and the destination key information decided by the key information supply unit for the input frame, an input port number of the input frame, and information other than the source MAC address and the destination MAC address in the input frame.