Apparatus and method for storing min terms in a central min term memory for efficient sharing by a plurality of network switch ports

摘要

A network switch, configured for performing layer 2 and layer 3 switching in an Ethernet (IEEE 802.3) network without blocking of incoming data packets, includes a plurality of network switch ports each 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 a central min term memory separate from each network switch port. A min term controller controls the fetching of min terms from the min term memory eliminating the need to store all min terms at each network switch port.