PC-DUOS: Fast TCAM Lookup and Update for Packet Classifiers Author: Tania Banerjee-Mishra, Sartaj Sahni,Gunasekaran Seetharaman Publisher: IEEE Symposium on Computers and Communications, 2011 Presenter: Jia-Wei Yo Date: 2011/08/31

Outline  Introduction  Background and Related Work  PC-DUOS  Experimental Results

Introduction  TCAM support high speed lookups. simple to use. used in conjunction with a SRAM. searched in parallel  The first match is used to access the corresponding SRAM word to retrieve the action.  Can determine the action in one TCAM cycle.

Background and Relate Work  PC-DUOS (Packet Classifier -DUOS) is an extension of DUOS  Use a binary trie in the control plane of the router to represent the prefixes  Matching rule with the lowest cost (highest priority)  Use DLFS_PLO memory management scheme.

PC-DUOS  LTCAM and ITCAM are searched in parallel  A match is found in the LTCAM, the ongoing search in the ITCAM is aborted.  Following requirements must hold: 1. No packet is matched by more than one rule in the LTCAM. 2. When a packet is matched by a rule in the LTCAM, the matched rule must be the highest priority matching rule.

PC-DUOS  LTCAM (Leaf TCAM) Store leaves of leaves set of rule Independent Matching rule with the highest priority  ITCAM (Interior TCAM) Store remaining rule Store the prefix in decreasing order of length

=> Only R2 store in LTCAM R3 overlaps with R1 => check the priority

PC-DUOS  Store rule in ITCAM Use priority graph Assigned block number to the rules No incoming edges are assigned block number to 0. Rules that are assigned the same block number are grouped together in a single block Enter in the TCAM in increasing order of assigned block numbers.

Experimental Results