Encoding Short Ranges in TCAM Without Expansion: Efficient Algorithm and Applications

Anat Bremler-Barr, Yotam Harchol*, David Hay, Yacov Hel-Or

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We present range encoding with no expansion (RENÉ) - a novel encoding scheme for short ranges on Ternary content addressable memory (TCAM), which, unlike previous solutions, does not impose row expansion, and uses bits proportionally to the maximal range length. We provide theoretical analysis to show that our encoding is the closest to the lower bound of number of bits used. In addition, we show several applications of our technique in the field of packet classification, and also, how the same technique could be used to efficiently solve other hard problems, such as the nearest-neighbor search problem and its variants. We show that using TCAM, one could solve such problems in much higher rates than previously suggested solutions, and outperform known lower bounds in traditional memory models. We show by experiments that the translation process of RENÉ on switch hardware induces only a negligible 2.5% latency overhead. Our nearest neighbor implementation on a TCAM device provides search rates that are up to four orders of magnitude higher than previous best prior-art solutions.

Original languageEnglish
Pages (from-to)835-850
Number of pages16
JournalIEEE/ACM Transactions on Networking
Issue number2
StatePublished - Apr 2018
Externally publishedYes


FundersFunder number
European Research Council259085
Seventh Framework Programme


    • Computer networks
    • information retrieval
    • nearest neighbor search
    • search methods
    • switching systems


    Dive into the research topics of 'Encoding Short Ranges in TCAM Without Expansion: Efficient Algorithm and Applications'. Together they form a unique fingerprint.

    Cite this