Finding nonequivalent classifiers to reduce ternary content addressable memory (tcam) usage

Abstract

The problem of providing an efficient physical implementation of a (first) classifier defined by a first rule set, at least a part of which first classifier having a sparse distribution in Boolean space, is solved by (1) converting the first classifier, having a corresponding Boolean space, into a second classifier, wherein the second classifier has a corresponding Boolean space which is not semantically equivalent to the Boolean space corresponding to the first classifier, and wherein the second classifier is defined by a second set of rules which is smaller than the first set of rules defining the first classifier; and (2) defining a bit string transformation which transforms a first bit string into a second bit string, wherein applying the first bit string to the first classifier is equivalent to applying the second bit string to the second classifier. In at least some example embodiments, the first bit string includes packet header information. In at least some example embodiments, the second classifier is implemented on a TCAM. In at least some example embodiments, the bit string transformation is implemented on an FPGA.