Minimizing the Number of Congested Links in OSPF Routing

Efficient network utilization using available resources is the main goal of traffic engineering and routing is the core criteria which regulates traffic over Internet links. Open Shortest Path First (OSPF) is a routing protocol which is widely used in the industry and uses the link weights as its routing metric. Optimizing these link weights leads to efficient routing and better network utilization. Setting weights on links for given traffic demands such that congestion can be avoided is an NP-hard problem. In this paper, tabu search, a non-deterministic iterative heuristic is applied to this problem using two different cost functions proposed in the literature. Moreover, we present the results for two additional performance metrics viz. number of congested links and percentage of extra load. This provides the network designer with more flexibility to optimize desired parameters based on the requirements. Our results show superior performance of tabu search over other heuristics.