Authors: Balajee Vamanan and T. N. VijaykumarConf. : ACM CoNEXT 2011Presenter : JHAO-YAN JIANDate : 2012/5/9

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TreeCAM: Decoupling Updates and Lookups in Packet Classification

INTRODUCTION Line rates increasing (40 Gbps now,

160 Gbps soon)Classifier size (number of rules)

increasingCustom rules for VPNs, QoS

Rules are getting more dynamic too Larger classifiers at faster lookup & update rates

Must perform well in lookups and updates at low power

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INTRODUCTIONTreeCAM: Three novel ideas

Dual tree versions to decouple lookups and updatescoarse tree in TCAM reduce lookup accesses

Tree/TCAM hybridfine tree in control memory reduce update

effortInterleaved layout of leaves to cut ordering effort

Performs well in lookups and updates6-8 TCAM accesses for lookups Close to ideal TCAM for updates

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TreeCAM Coarse TreeIdea: partition rules among TCAM subarrays

using decision trees4k-entry subarrays coarse tree with each leaf

in a subarray2-deep tree fast lookup

Packets traverse subarrays

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TreeCAM Fine TreeKey observation: A

packet cannot match multiple leaves only rules within the same leaf need ordering

Reduce update effort Tree with small binth – fine tree

One coarse-tree leaf contains some contiguous fine-tree leaves

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Updating - No Re-balancing

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Updating - Local Re-balancing

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Updating - Global Re-balancing

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EXPERIMENTAL

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EXPERIMENTAL

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EXPERIMENTAL

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EXPERIMENTAL

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