PC-DUOS: Fast TCAM Lookup and Update for Packet Classifiers

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

2. Outline • Introduction • Background and Related Work • PC-DUOS • Experimental Results

3. 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.

4. 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.

6. 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.

7. 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

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

9. 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.

10. Experimental Results

11. Experimental Results

12. Experimental Results