Energy Efficient Content Distribution

In this chapter, the authors investigate the power consumption associated with content distribution networks. They study, through Mixed Integer Linear Programming (MILP) models and simulations, the optimization of data centre locations in a Client/Server (C/S) system over an IP over WDM network so as to minimize the network power consumption. The authors investigate the impact of the IP over WDM routing approach, traffic profile, and number of data centres. They also investigate how to replicate content of different popularity into multiple data centres and develop a novel routing algorithm, Energy-Delay Optimal Routing (EDOR), to minimize the power consumption of the network under replication while maintaining QoS. Furthermore, they investigate the energy efficiency of BitTorrent, the most popular Peer-to-Peer (P2P) content distribution application, and compare it to the C/S system. The authors develop an MILP model to minimize the power consumption of BitTorrent over IP over WDM networks while maintaining its performance. The model results reveal that peers co-location awareness helps reduce BitTorrent cross traffic and consequently reduces the power consumption at the network side. For a real time implementation, they develop a simple heuristic based on the model insights.