Clustered Hierarchical Search Structure for Large-Scale Packet Classification on FPGA Publisher : Field Programmable Logic and Applications, 2011 Author : Oguzhan Erdem, Hoang Le, Viktor K. Prasanna Presenter : Yu-Hsiang Wang Date : 2011/11/09

Outline Related Work Clustered Hierarchical Search Structure(CHSS) Architecture Performance evaluations

Related Work Backtrack : the search needs to proceed in the backward direction and requires stalling the pipeline.

Clustered Hierarchical Search Structure Clustering algorithm : partition a given ruleset based on the SA field to eliminate backtracking from DA trie to the SA. In each cluster, the prefixes are pairwise disjoint. The number of clusters is at most 4 in the real life and synthetic rulesets.

Clustered Hierarchical Search Structure

Clustered Hierarchical Search Structure A range tree is built for each leaf prefix node of a DA trie if the number of rules at the node exceeds a predefined threshold.

Clustered Hierarchical Search Structure Define two parameters : NRtrie, NRtree NRtrie: remaining rules of DA trie node > NRtrie leaf node => DP tree non-leaf node => TCAM NRtree : remaining rules of DP tree > NRtree => TCAM TCAM include: (1) the non-leaf DA trie rules (2) the excessive DP tree rules. NRtrie and NRtree provide the trade-off between the size of the on-chip memory and TCAM.

Architecture

Performance evaluations We set a limit on αT = 0.1 (the ratio of the number of rules stored in the TCAM over the total number of rules of the given ruleset).

Performance evaluations Xilinx ISE 12.4, with Xilinx Virtex-5 XC5VFX200T with −2 speed grade