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Range Encoding

Cheng-Chien Su

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Outline DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors

Hao Che, Zhijun Wang, Kai Zheng, Bin Liu IEEE Trans. Computers, 2008.

Packet Classifiers In Ternary CAMs Can Be Smaller Qunfeng Dong, Suman Banerjee, Jia Wang, Dheeraj Agrawal, Ashutosh Shukla Proc. ACM SIGMetrics, 2006

TCAM Razor: A Systematic Approach Towards Minimizing Packet Classifiers in TCAMs

Chad R. Meiners, Alex X. Liu, Eric Tomg Proc. IEEE ICNP, 2007

Layered Interval Codes for TCAM-based Classification Anat Bremler-Barr, Herzliya, David Hay, Danny Hendler, Boris Farber Proc. ACM SIGMetrics, 2008

Efficient Multi-Match Packet Classification with TCAM Fang Yu, Randy H. Katz Proc. IEEE HOTI, 2004

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DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors (1/5)

Why is DRES? Why is Code Vector? Why is Index Vector?

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DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors (2/5) Dynamic Range Selection Algorithm

Selecting m ranges for encoding out of n ranges. Si is the number of subranges needed to exactly impl

ement range Ri in a TCAM. Ei is the number of rule entries to implement all of the

rules that contain range Ri. Gi is the encoding gain for Ri, defined as the number

of rule entries that can be eliminated if Ri is encoded. To select m ranges to be encoded, m steps are r

equired, each selecting one range.

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DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors (3/5)

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DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors (4/5)

Ranges R1-R5 come from the destination port field. R1{256, 512}, R2{768, 2047}, R3{6000, 6064}, R4{>1023}, R5{512, 1536}

Ranges R6-R7 ranges come from the source port field. R6{>1023}, R7{256, 512}.

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DRES: Dynamic Range Encoding Scheme for TCAM Coprocessors (5/5)

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Packet Classifiers In Ternary CAMs Can Be Smaller (1/6)

Their proposed techniques for defining semantically equivalent packet classifiers requiring fewer TCAM entries to represent.

Expanding Rule Trimming Rule Adding Rule Merging Rule

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Packet Classifiers In Ternary CAMs Can Be Smaller (2/6)

Expanding Rule

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Packet Classifiers In Ternary CAMs Can Be Smaller (3/6)

Trimming Rule

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Packet Classifiers In Ternary CAMs Can Be Smaller (4/6)

Adding Rule

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Packet Classifiers In Ternary CAMs Can Be Smaller (5/6)

Merging Rule

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Packet Classifiers In Ternary CAMs Can Be Smaller (6/6)

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TCAM Razor: A Systematic Approach Towards Minimizing Packet Classifiers in TCAMs