Unifying Top-Down and Bottom-Up Approaches to Evaluate Network Energy Consumption

A novel method for estimating energy consumption of networks at the national scale is presented. Accurate estimations of network energy consumption are increasingly important because of continuously increasing network traffic and the need to assess emerging energy technologies to achieve overall energy efficiency. However, direct estimations are not practical because of the complex, widely diverse, and undisclosed configurations of actual networks. The impact of each network´s energy overhead, which is the energy consumed above that required to accommodate network traffic, on the energy consumption associated with these complex configurations must be inferred. In the proposed method, the energy overhead is quantitatively evaluated and introduced as overhead factors by comparing the energy consumption estimated from network configuration models (bottom-up methods) with reports of actual energy consumption (top-down methods). This proposed “unified” method is capable of long-term predictions of future technology trends, including network architecture changes. In this paper, we consider different overhead factors that serve as fitting parameters for different network areas, and demonstrate the procedure for determining each of these parameters through an estimation of the fixed broadband Internet in Japan. This unified method consistently estimates the long-term evolution of energy consumption from 2000 to 2030.