A
packet switching node having a pipelined
packet processing architecture
processing packets received via an input port associated with the
packet switching node is presented. The method performed by the apparatus includes: determining a packet frame type of the packet received; selectively extracting packet header field values specific to a packet frame type, the extracted packet header field value including packet addressing information; ascribing to the packet a preliminary action to be performed in respect of the packet; searching
packet switching information tracked by the
packet switching node based on extracted packet addressing information; formulating a preliminary switch response for the packet; classifying the packet into one of a plurality of packet flows; modifying the preliminary switch response in accordance with one of the preliminary action, the packet flow into which the packet was classified, and a default port action corresponding to the input port; modifying the packet header in accordance with one of the preliminary action, the packet flow, and the default port action; and
processing the packet in accordance with the switch response. Advantages are derived from: pipelined
processing of packets which enables short-
cutting the rest of the processing for improper packets; a flexible frame type determination which is fast for well know frame types yet flexible in support of new frame types delaying
obsolescence of a particular implementation; an early determination of a processing action which is successively refined by subsequent stages; a combined Layer-2 and Layer-3
network addressing search engine operating on short
bit length indexed Layer-2 and Layer-3 network addresses reducing
network address table storage requirements, requiring a reduced data transfer bandwidth for
network address table access, a large external hashed primary
network address table, and a small internal secondary network address table; an early determination of a switch response; and packet-classification-based switch response and packet header modification.