Energy-Conserving Switch Architecture for LANs

Reducing energy consumption in the Internet has become an increasingly important goal recently. Previous work on reducing energy consumption has primarily looked at either changing link rates or putting interfaces to sleep. Due to the unpredictable nature of traffic, the energy savings achieved have been modest, do not scale, and incur losses and delay. This paper proposes a different approach to the problem which involves a new switch architecture combined with a simple sleep/awake algorithm. The main results we obtain are that energy consumption, measured as the fraction of interfaces that are awake, scales linearly with load for all loads with no delay and very low packet loss. We demonstrate the behavior of the algorithm via detailed simulations using synthetic traffic and traffic traces collected at a LAN switch in our university. We obtain over 90% energy saving in all real traffic traces and zero packet loss. For the synthetic traces, we see linear scaling of energy use with load of up to 85%.