BitTorrentSW: A Sleep-and-Wake Approach to Reduce Energy Consumption in BitTorrent Networks

File sharing over peer-to-peer networks has been one of the most important Internet applications over the past twenty years. Given the very large number of hosts involved in peer-to-peer networks, reducing their aggregate energy consumption is an important challenge to be faced. In this paper, we study how the sleep-and-wake energy saving approach can be used to reduce energy consumption in BitTorrent, one of the most popular file sharing peer-to-peer networks. We introduce BitTorrentSW, a sleep-and-wake approach for BitTorrent networks that allows peers to cyclically switch between wake and sleep mode to save energy while ensuring good file sharing performance. The decision to get in sleep mode is taken independently by each peer based on local information about the composition of the peer-to-peer network. BitTorrentSW has been evaluated through PeerSim using real BitTorrent traces. The simulation results show that about 40% of energy is saved using BitTorrentSW, with only an increase of 5% of the average time needed to complete a file download compared to a standard BitTorrent network in which all peers are always powered on.