Performance bounds of rate-adaptation schemes for energy-efficient routers

To maximize the energy efficiency of packet networks, energy use in network equipment should scale rigorously with the traffic load. Rate adaptation is gaining popularity as a promising framework for achieving energy proportionality in the data-path components of routers and switches, but a thorough characterization of its energy-saving capabilities and impact on network performance is still lacking. In this paper, we present novel rate-adaptation schemes that are easy to implement, amenable to incremental deployment in packet switches and routers, and whose negative effect on end-to-end packet delays is bounded. We derive tight lower and upper bounds on energy consumption that we use to further refine the design of our schemes. Our analysis indicates that large-scale deployments of rate adaptation can enable substantial energy savings, as large gains can be attained in individual data-path devices under parametric configurations that do not compromise the end-to-end delay performance of the network.