Apparatus and method for storing min terms in a network switch port memory for identifying data packet types in a real time

Abstract

A network switch, configured for performing layer 2 and layer 3 switching in an Ethemnet (IEEE 802.3) network without blocking of incoming data packets, includes a network switch port having a filter (i.e., a packet classifier module) configured for evaluating an incoming data packet on an instantaneous basis. The filter performs simultaneous comparisons between the incoming data stream of the data packet and multiple templates configured for identifying respective data protocols, enabling the network switch to perform layer 3 switching for 100 Mbps and gigabit networks without blocking in the network switch. Each template is composed of a plurality of min terms, wherein each min term specifies a prescribed comparison operation within a selected data byte of the incoming data packet. The templates may be programmed by a user and stored in an intemnal min term memory. A min term controller controls the storage of the min terms in the min term memory by determining for each min term a corresponding relevance of the corresponding selected data byte in evaluation of the incoming data packet. The min term controller stores each of the min terms in selected memory blocks of the min term memory based on the corresponding relevance to evaluation of the incoming data packet, enabling storage of the min terms to be optimized for simultaneous comparisons of the most relevant data bytes of the incoming data packet as they are received.