Sleep mode at the edge: How much room is there?

Access networks contribute to a large portion of the energy consumed in telecommunication networks. Up to now, several approaches have been proposed to reduce their energy consumption. For example, ADSL2 standards define a low power state that modem can enter to save energy. Yet, none or little deployment of these technologies has been done. The aim of this work is to understand how much energy savings these technologies would allow to reach when deployed in real scenarios. To this goal we consider a large data set of ADSL line traffic profiles out of which we evaluate the efficiency of sleep mode policies. Results show that, on average, users are typically inactive for long periods of time. This permits to achieve significant savings even with very simple and not aggressive policies, with little or marginal impact on the QoS perceived by the users.