Energy-efficient core networks

In this paper, we optimize core networks to minimize the embodied energy and the operational energy and introduce two measures for energy minimization in core content distribution networks: data compression in optical networks and locality in P2P networks. We investigate the impact of taking the embodied energy of network devices into account in the physical topology optimization and compare it to optimizing the physical topology considering operational energy only. The results show significant embodied energy savings up to 59%, resulting in a total energy saving of 47%. We also investigate energy-efficient data compression for optical networks and how to achieve a trade-off between the power consumption of computational resources and memory required to compress and decompress data and the network power savings. The results show that optimizing the data compression ratios in IP over WDM networks considering the non-bypass approach has saved up to 55% of the network´s power consumption. Furthermore, we evaluate the power consumption of BitTorrent, the most popular P2P content distribution protocol, over IP over WDM networks and compare it to client/server (C/S) systems. The results reveal that the power-minimized BitTorrent converges to locality in order to achieve lower power consumption, resulting in 36% power savings compared to the C/S model.