Energy-Efficient Peer Selection Mechanism for BitTorrent Content Distribution

In this paper, we evaluate the energy consumption of BitTorrent based peer to peer (P2P) content distribution systems in bypass IP/WDM core networks and compare it to client-server (C/S) systems. A Mixed Integer Linear Programming (MILP) model is developed to carry out the comparison. Our results for homogeneous peers with similar upload capacities show that the original BitTorrent, based on random peer selection, has comparable energy consumption to the C/S model. The results also reveal that the power-minimized BitTorrent model achieves 30% energy savings compared to the C/S model as it converges to locality. Furthermore, a heterogeneous BitTorrent system with two upload capacity classes is investigated and the results show a 50% reduction in energy consumption compared to a C/S model. For real-time implementation, we develop a simple heuristic based on the model insights. Comparable power savings are achieved with a reduction of only 13% in the download rate.