Nondeterministic finite automata for high-speed network

With the rapid increase of the network bandwidth, implementing regular expression with hardware has become inevitable. This paper presents a FPGA-based NFA algorithm to achieve a regular expression, which separates the regular expression into wildcard strings and fixed strings, and implement both types pattern matching with a similar structure. It reduces the complexity of programming and takes full advantage of the characteristics of the FPGA. Experimental results show that the implementation is able to process many characters per one clock cycle, and to run at high frequency. Thus the algorithm enables the matching of regular expressions in high-speed network.