PBC: Effective Prefix Caching for Fast Name Lookups

Chuwen Zhang, Yong Feng, Haoyu Song, Beichuan Zhang, Yi Wang, Ying Wan, Wenquan Xu, Bin Liu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Name lookup based on the Longest Prefix Match (LPM) is a basic function in many network applications. Caching is usually used to speed up the lookups. However, caching prefixes for LPM has a unique challenge: one needs to guarantee a cached prefix is indeed the longest for correctness. To achieve this, existing solutions have to cache either the entire prefix triebranch or only the leaf nodes, which undermines cache utilization and thus reduce the hit ratio. In this paper, we propose PlusBitmap Caching (PBC), which associates a bitmap to each cached prefix to denote the existence or absence of any longer prefix in the main table. This bitmap not only guarantees the correctness of LPM lookup, but also minimizes the extra information stored in cache. Meanwhile, cache consistency for prefix updates can be efficiently maintained. Experimental results show that, compared with previous work, PBC increases cache hit ratio by 16% over a wide range of cache size, and exhibits a more steady performance when more non-leaf prefixes are hit or a prefix is hit by more different names. PBC is a general approach that can be applied to other LPM-based applications.

Original languageEnglish (US)
Title of host publicationIFIP Networking 2020 Conference and Workshops, Networking 2020
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages9
ISBN (Electronic)9783903176287
StatePublished - Jun 2020
Event2020 IFIP Networking Conference and Workshops, Networking 2020 - Paris, France
Duration: Jun 22 2020Jun 25 2020

Publication series

NameIFIP Networking 2020 Conference and Workshops, Networking 2020


Conference2020 IFIP Networking Conference and Workshops, Networking 2020

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Hardware and Architecture
  • Information Systems and Management
  • Safety, Risk, Reliability and Quality


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