Multi-Stride Decision Trie for IP Address Lookup

Abstract

Multi-bit tries have been proposed to improve the search performance of a binary trie by providing flexibility in stride values, which identify the number of bits examined at a time. However, constructing a variable-stride multi-bit trie is challenging since it is not easy to determine a proper stride value that satisfies the required performance at each node. The aim of this paper is to identify several desired characteristics of a trie for IP address lookup problems, and to propose a multi-stride decision trie that has these characteristics. Simulation results using actual routing sets with about 30,000 to 220,000 prefixes show that the proposed multi-stride decision trie has the desired characteristics and achieves IP address lookup using 33% to 47% of the 2-bit trie in the average number of node accesses, while requiring a smaller amount of memory.