Reaching approximate Wardrop equilibrium at reduced costs of link state updates

Several routing protocols have been proposed to take advantage of the dynamic metrics on links such as link delays, queueing lengths, and available link bandwidths.Wardrop routing, QOS routing are few such example routing protocols. Even when these protocols can be shown to offer convergence properties without oscillations, the protocols have not been widely adopted for a number of reasons. The expected cost of keeping the link metrics updated at various nodes in the network being one of them. In this paper, we study the problem of reducing the cost of propagating dynamic link metrics while keeping the quality of paths within a margin of error. We propose a simple technique of threshold-based metric propagation that is shown, through analysis and simulations, to offer bounded guarantees on path quality while significantly reducing the cost of propagating the dynamic link metric information. Our results indicate that threshold based updates can reduce the number of link updates by up to 90-95% in some cases.