Pattern matching values of a packet which may result in false-positive matches

Abstract

In one embodiment, a packet switching device determines that a packet matches one of a plurality of predetermined patterns, however, this matching may produce a false-positive match of one of the underlying rules corresponding to the plurality of predetermined patterns. In one embodiment, determining the packet matches one of the plurality of predetermined patterns includes determining a first pattern match of a packet when each particular portion of a plurality of different portions of the packet is found to be matching a corresponding particular pattern portion by performing a table lookup operation based on the particular portion as an address in a corresponding different current portion-iteration table to retrieve a corresponding partial result. In one embodiment, the first pattern match is filtered using a second validation technique for removing false-positive first pattern matches. In one embodiment, the second validation technique includes using hashing.