Chapter 9 Energy Efficiency in P 2 P Systems and Applications

P2P systems and applications have achieved increasing popularity in the last years due to the characteristics of dynamicity and scalability of the peer-to-peer paradigm. Currently, P2P applications – especially file sharing and file distribution applications – generate a remarkable portion of the overall Internet traffic. However, many common P2P protocols do not consider the energy problem. Frequently, hosts are requested to stay on and connected to the network for long times. Therefore, they are very energy-consuming. In this chapter, we present a general taxonomy to classify possible approaches to the energy problem in P2P systems and applications. Then, we survey the main solutions available in the literature, focusing on two relevant classes of P2P protocols, namely file sharing/distribution protocols (e.g., BitTorrent and Gnutella) and epidemic P2P protocols.