Efficient Gray Code Based Range Encoding Schemes for Packet Classification in TCAM

Author: Yeim-Kuan Chang, Cheng-Chien Su, and Yung-Chieh Lin

Publisher: Submit to Transactions on Computers

Presenter: Chun-Yi Li

Date: 2008/12/24

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Outline Preliminary

Related Works

EIGC

Perfect-BRGC (P-BRGC)

Performance

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PreliminaryBuddy Code & BRGC :

Elementary interval

Related WorksDatabase independent & database dependentDirect range-to-prefix conversion:

Database independent schemeConvert each range to prefixes

ex:R=[1,14] prefix = 0001, 001*, 01**, 10**, 110*, 1110Ternary string(Boolean expression)

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Related Works

Elementary interval based encoding

R1=0101, 0110 R2=0001R3=01** R4=0011, 010*

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Related WorksParallel packet classification encoding

Proposed Range Encoding Scheme

Scheme based on Elementary Interval and BRGC (EIGC)

Assign each elementary interval a identifier by using BRGC

Default elementary interval have the same code.

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Proposed Range Encoding Scheme

Scheme based on Perfect BRGC Range Sets (P-BRGC)Definition1:Any range in the set must intersect at least

one of the other ranges

Definition2:A perfect BRGC range sets satifies

(1)Each range contain 2n elementary intervals

(2)Two intersection range A and B in the set, share elementary interval must be

equal to half of the number of elementary interval contained in either A or B.

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Perfect BRGC range sets

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Perfect BRGC range sets

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Virtual endpoint insertShould limit the number of virtual endpoints

Perfect BRGC range sets

Insert a range into layers

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Performance

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Performance

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Performance – All rules

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Performance - Non-prefix rules

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