1 / 13

DFA-NFA Hybrid Circuit for Regular Expression Matching

This article presents a design method for a regular expression matching circuit based on a decomposed automaton. The circuit reduces the number of logic cells, resulting in cost reduction. The article explains the realization of a merged-states non-deterministic finite automaton with unbounded string transitions using a DFA and an NFA. It also discusses the design of transition string detection and state transition circuits. The experimental results show the effectiveness of the proposed method using SNORT regular expressions on a Xilinx Spartan III FPGA.

glassf
Download Presentation

DFA-NFA Hybrid Circuit for Regular Expression Matching

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Design Method of a Regular Expression Matching Circuit Based on Decomposed Automaton Author: Hiroki Nakahara, Tsutomu Sasao and Munehiro Matsuura Publisher: IEICE TRANS. INF.& SYST., 2012 Presenter: Li-Hsien, Hsu Data: 4/25/2012

  2. Introduction • The cost for the FPGA is proportional to the number of LCs(logic cells), reduction of the number of LCs means reduction of the system cost.

  3. DFA

  4. NFA

  5. MNFAU (Merged-states non-deterministic finite automaton with unbounded string transition)

  6. MNFAU

  7. Realization of MNFAU • An MNFAU is decomposed into a DFA and an NFA.

  8. Realization of MNFAU • Transition string detection circuit Since each state of the MNFAU consists of different number of states of the NFA, lengths of the transition strings for states of the MNFAU are different. To detect multiple strings with different lengths, we use the Aho-Corasick DFA.

  9. Realization of MNFAU • State transition circuit When the AC-DFA detects the transition string, a detection signal is sent to the state transition circuit. Then, the state transition is performed.

  10. Design flow

  11. Analysis using SNORT

  12. Experimental Results • We selected regular expressions from SNORT. • Xilinx Spartan III FPGA • The total number of regular expression is 1114. • This implementation requires 19522 LCs, and an off-chip memory of 16 Mbits.

More Related