QoS-aware overlay routing with limited number of alternative route candidates and its evaluation

A recent trend in routing research is the use of overlay routing to improve end-to-end QoS without changing the network-level architecture. The key of this technology is to find an alternative route that can avoid congested routes, using an overlay network. Developing cost-efficient overlay routing in terms of calculation cost and information distribution cost needed to find an alternative route is important for deploying QoS-aware overlay routing. Thus, this paper evaluates how effective overlay routing can be when the number of alternative route candidates is limited to reduce costs. Evaluation results using actual measurement data indicate that overlay routing is still effective even if alternative route candidates are limited to 1/4 of all possible alternative routes. We also discuss an overlay routing algorithm to enable us to find an appropriate route under the constraint that the number of alternative route candidates is limited.