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The ACM Journal of Experimental Algorithmics


Volume 8 Article 3, 2003


Fast Prefix Matching of Bounded Strings

by

Adam L. Buchsbaum

and

Glenn S. Fowlder

a nd

Balachannder Kirishnamurthy

and

Kiem-Phong Vo

and

Jia Wang


http://www.jea.acm.org/2003/BuchsbaumFast/

Abstract:

Longest Prefix Matching (LPM) is the problem of finding which string from a given set is the longest prefix of another, given string. LPM is a core problem in many applications, including IP routing, network data clustering, and telephone network management. These applications typically require very fast matching of boundes strings, i.e., strings that are short and based on small alphabets. We note a simple correspondence between bounded strings and natural numbers that maps prefixes to nested intervals so that computing the longest prefix matching a string is equivalent to finding the shortest interval containing its corresponding integer value. We then present retries a fast and compact data structure for LPM on general alphabets. Performance results show that retires ofent outperform previously published data structures for IP look-up. By extending LPM to general alphabets, retries admit new applications that oculd not exploit prior LPM solutions designed for IP look-ups.

Keywords: Algorithms, Experimentation, Measurement, Performance, Theory, IP routing, prefix matching, table look-up, tries

Categories: D.2.8. [Software Engineering]: Metrix-Performance Measures; E.1 [Data Structures]: Arrays; Recors; E.2 [Data Storage Representations]: Linked Representations; F.2.2 [Analysis of Algorithms and Problem Complexity]: Nonumerical Algorithms and Problems - Pattern Matching. G.4 Mathematical Software: Algorithm Design and Analysis