Energy profiling of ISP points of presence

Points of Presence (PoP), large aggregation nodes of a telecommunication network in which users lines are interconnected to the ISP backbone network, are relevant elements of the ISP network infrastructure. Motivated by the today interest of both ISPs and researchers to more energy efficient Internet, we investigate the power consumption of PoPs of FASTWEB, a national-wide ISP in Italy. Energy profiling spans a period of one year, and includes both ADSL and FTTH access technologies. This extensive and unique dataset allows us to shed light on energy consumption of ISP networks, which we profile against other measurements, such as external temperature and PoP handled traffic. Results show that energy consumption is independent on the traffic, while it is strongly correlated with both daily and annual variability of temperature, due to air conditioning energy cost. Starting from these results, we investigate some possible strategies to reduce ISP electricity bill. We consider the adoption of energy proportional architectures which are currently being investigated by both manufacturers and researchers. Moreover, we evaluate the possible energy savings using real traffic data and we obtain that simple PoPs energy saving models based on two-three energy operating configuration can achieve results comparable to fully energy proportional model.