A hybrid genetic algorithm for the weight setting problem in OSPF/IS-IS routing

Intradomain traffic engineering aims to make more efficient use of network resources within an autonomous system. Interior Gateway Protocols such as OSPF (Open Shortest Path First) and IS-IS (Intermediate System-Intermediate System) are commonly used to select the paths along which traffic is routed within an autonomous system. These routing protocols direct traffic based on link weights assigned by the network operator. Each router in the autonomous system computes shortest paths and creates destination tables used to direct each packet to the next router on the path to its final destination. Given a set of traffic demands between origin-destination pairs, the OSPF weight setting problem consists of determining weights to be assigned to the links so as to optimize a cost function, typically associated with a network congestion measure. In this article, we propose a genetic algorithm with a local improvement procedure for the OSPF weight-setting problem. The local improvement procedure makes use of an efficient dynamic shortest path algorithm to recompute shortest paths after the modification of link weights. We test the algorithm on a set of real and synthetic test problems, and show that it produces near-optimal solutions. We compare the hybrid algorithm with other algorithms for this problem illustrating its efficiency and robustness. (c) 2005 Wiley Periodicals, Inc.