PEDS: A parallel error detection scheme for TCAM devices

Anat Bremler-Barr*, David Hay, Danny Hendler, Ron M. Roth

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Ternary content-addressable memory (TCAM) devices are increasingly used for performing high-speed packet classification. A TCAM consists of an associative memory that compares a search key in parallel against all entries. TCAMs may suffer from error events that cause ternary cells to change their value to any symbol in the ternary alphabet "0", "1", "*". Due to their parallel access feature, standard error detection schemes are not directly applicable to TCAMs; an additional difficulty is posed by the special semantic of the " *" symbol. This paper introduces PEDS, a novel parallel error detection scheme that locates the erroneous entries in a TCAM device. PEDS is based on applying an error-detection code to each TCAM entry, and utilizing the parallel capabilities of the TCAM, by simultaneously checking the correctness of multiple TCAM entries. A key feature of PEDS is that the number of TCAM lookup operations required to locate all errors depends on the number of symbols per entry rather than the (orders-ofmagnitude larger) number of TCAM entries. For large TCAM devices, a specific instance of PEDS requires only 200 lookups for 100-symbol entries, while a naive approach may need hundreds of thousands lookups. PEDS allows flexible and dynamic selection of trade-off points between robustness, space complexity, and number of lookups.

Original languageEnglish
Title of host publicationIEEE INFOCOM 2009 - The 28th Conference on Computer Communications
Pages1296-1304
Number of pages9
DOIs
StatePublished - 2009
Externally publishedYes
Event28th Conference on Computer Communications, IEEE INFOCOM 2009 - Rio de Janeiro, Brazil
Duration: 19 Apr 200925 Apr 2009

Publication series

NameProceedings - IEEE INFOCOM
ISSN (Print)0743-166X

Conference

Conference28th Conference on Computer Communications, IEEE INFOCOM 2009
Country/TerritoryBrazil
CityRio de Janeiro
Period19/04/0925/04/09

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