Influence of link state updating on the performance and cost of QoS routing in an intranet

QoS routing has been regarded as an essential enhancing mechanism for providing differentiated QoS in the IP networks. QoS routing needs link state updating algorithms for acquiring accurate link state information (e.g., available link bandwidth) to compute routes. However, an unsuitable link state updating also brings excess computation and communication cost so that seriously degrades the performance of QoS routing. In this paper, we present four link state update algorithms for QoS routing in an Intranet, i.e., period based, threshold based, equal class based, and unequal class based updating. By doing extensive simulations, we investigate and compare their impact on the performance and cost of on-demand QoS routing in an intranet. Our simulation results prove that QoS routing can achieve both high performance and low cost under the careful selection of link state updating algorithms and their parameters.