Load-balancing solutions for static routing schemes in ATM networks
Abstract In this paper, we present two different path ordering algorithms whose aim is balancing the load among network links when used in conjunction with static routing algorithms. Both algorithms have the same aim, but use different heuristics. A new formalism based on set theory is defined in order to allow a formal description of the problem and of the two algorithms devised to solve it. The first selection criterion we define tries, as a general rule, to allocate the shortest paths first, thus aiming at reducing bandwidth waste due to routing over long paths. The second one attempts to allocate paths for every source-destination pair, trying to assign the primary paths first, then the alternate ones. We compare the two routing schemes by simulating them in both simple and complex topologies, using ATM Networks Call LEvel Simulator (ANCLES), a tool developed by the Electronics Department of Politecnico di Torino in cooperation with Telecom Italia Research Center (CSELT). Performance metrics include the network call blocking probability and the load distribution between links. Also, we show how our algorithms restrict the path search to a narrower set, thus effectively decreasing the call setup times. Results are compared with those obtained by routing without load balancing on both a symmetric and an asymmetric traffic scenario.