US Patent 7933282 Packet classification device for storing groups of rules

A packet classification device includes a CAM device, an SRAM device, and a control circuit that controls and coordinates the operations of the CAM and SRAM devices. For some embodiments, a first CAM block stores unique entries for each packet header field, a RAM block coupled to the first CAM block stores field labels for the unique packet header fields, a second CAM block stores group labels consisting of unique combinations of concatenated field labels, and a second RAM block coupled to the second CAM block stores a group identification (ID) for each group label, wherein each group ID identifies a corresponding one of the groups of rules.