PTSPM: A Novel PTS Based Prefix Matching Scheme with Reduced Collision for IPv6 Routers

Abstract

Internet address lookup is a challenging problem because of the increasing routing table sizes, increased traffic, higher speed links, and the migration to 128 bit IPv6 addresses. Routing lookup involves computation of best matching prefix for which existing solutions scale poorly when router traffic increases or when employed for IPv6 address lookup. Our paper describes a novel parallel ternary search based prefix matching (PTSPM) scheme with reduced collision for IPv6 routers. This approach employs multiple hashing on reduced number of hash tables on which parallel ternary search (PTS) on levels is applied. This scheme handles large number of prefixes generated by controlled prefix expansion by reducing collision and distributing load fairly in the hash buckets thus providing faster worst case and average case lookups. The approach we describe is fast, simple, scalable, parallelizable, and flexible.