Patent ID: 7286535

Claim:
A packet forwarding device connected to a plurality of input and output ports for forwarding a packet received from one of the input ports to one of the output ports specified by header information of the packet, the packet forwarding device comprising: a flow classifier for classifying the packet into one of packet flows to which the packet belongs, according to the header information of the packet; and means for executing on the packet a forward control previously designated for said one packet flow; wherein the flow classifier includes: a flow Content Addressable Memory (CAM) having a plurality of flow entries; a search key generator for generating a search key having a variable format which differs depending on a combination of information items to constitute a flow condition; and a table for specifying the forward control to be executed on the packet in response to an address of a flow entry outputted from said flow CAM, wherein said flow CAM includes a plurality of table regions corresponding to the format of the search key, each of said table regions includes a plurality of flow entries each including a plurality of information fields for indicating values of information items to constitute the flow condition and excluding information fields containing information which is not necessary for a respective input logical link, wherein all of the flow entries in said flow CAM are compared with the search key to output an address of one of the flow entries matched with the search key, and the search key includes at least one header information item extracted from the header of the packet.