Experimental Evaluation of Algorithms for IP Table Minimization

The continuous growth of the routing tables sizes in backbone routers is one of the most compelling scaling problems affecting the Internet and has originated considerable research in the design of compacting techniques. Various algorithms have been proposed in the literature both for a single and for multiple tables, also with the possibility of performing address reassignments [1,5]. In this paper we first present two new heuristics, the BFM and its evolution called BFM-Cluster, that exploit address reassignments for the minimization of n > 1 routing tables, and their performances are experimentally evaluated together with the already existing techniques. Since a main problem posed by the growth of the routing tables sizes is the consequent general increase of the table lookup time during the routing of the IP packets, the aim is twofold: (i) to measure and compare the compression ratios of the different techniques and (ii) to estimate the effects of the compression on the lookup times by measuring the induced improvement on the time of the main algorithms and data structures for the fast IP address lookup from the original tables to the compressed ones. Our point is that the existing methods are efficient in different situations, with BFM-Cluster heuristic outperforming all other ones.