Abstract

Srinivasan and Varghese [17] have proposed the use of multibit tries to represent routing tables used for Internet (IP) address lookups. They propose an ################ dynamic programing algorithm to determine the strides for an optimal variable-stride trie that has at most levels. Here, is the number of prefixes in the routing table and length of the longest prefix. We improve on this algorithm by providing an alternative dynamic programming formulation. The complexity of our algorithm is , on real router data sets. This is an improvement by a factor of over the corresponding algorithm of [17]. Experiments conducted by us indicate that our variable-stride algorithm is between 2 and 17 times as fast for IPv4 routing table data. Keywords: Packet routing, longest matching prefix, controlled prefix expansion, multibit trie, dynamic programming. 1

Citations