MULTIPROTOCOL PACKET RECOGNITION AND SWITCHING

The invention provides a method and system for identifying header information in a packet header, and for switching (and otherwise operating) on the packet in response thereto. A first set of header information recognizers operate in parallel on selected words of the packet header so as to recognize a header format for the packet header and to determine header information in response to that header format. A second set of header information recognizers operates on the header information to select a set of words from the packet header which are used for lookup for treatment of the packet. The same or similar header information is located in the packet header responsive to information which determines an encapsulation type for the packet, such as packets which use the IP version 4, IP version 6, or IPX protocols. The header information can include the destination address for the packet, or some combination of the destination address and additional information; the additional information can include the sending address, the input interface, a number of bits matched for the destination address, or some combination thereof.