Load-balancing solutions for static routing schemes in ATM networks

In this paper, we present two diierent 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 diierent heuristics to obtain it. A new formalism based on set theory is deened in order to allow a formal description of the two algorithms. The rst selection criterion we deene tries, as a general rule, to allocate the shortest paths rst, thus aiming at reducing bandwidth waste due to routing over long paths. The second one attemps to allocate paths for every source-destination pair, trying to assign the primary paths rst, then the alternate ones. We compare the two routing schemes by simulating them in both simple and complex topologies, using ANCLES (ATM Networks Cell LEvel Simulator), a tool developed by the Electronic Department of Politecnico di Torino in cooperation with CSELT (Telecom Italia Reseach Center). Performance metrics comprise the global network call blocking probability and the load balancing between links. Results are compared with those obtained by routing without load balancing.