How Much Can The Internet Be Greened?

The power consumption of the Internet is becoming more and more a key issue, and several projects are studying how to reduce its energy consumption. In this paper, we provide a first evaluation of the amount of redundant resources (nodes and links) that can be powered off from a network topology to reduce power consumption. We first formulate a theoretical evaluation that exploits random graph theory to estimate the fraction of devices that can be removed from the topology still guaranteeing connectivity. Then we compare theoretical results with simulation results using realistic Internet topologies. Results, although preliminary, show that large energy savings can be achieved by accurately turning off nodes and links, e.g., during off-peak time. We show also that the non-cooperative design of the current Internet severely impacts the possible energy saving, suggesting that a cooperative approach can be investigated further.