Network monitoring for energy efficiency in large-scale networks: the case of the Spanish Academic Network

The energy consumption due to information technologies is large and there are many ongoing efforts to cut it down. Previous studies have shown that there is a significant percentage of hosts which are left switched on in office buildings at night and weekend, whose energy consumption is significant. This motivates the development of techniques that can detect switched-on hosts in a simple and scalable way. This paper proposes detection techniques based on network traffic monitoring. The results show that such techniques can effectively detect switched-on hosts in small-medium campus networks and also in large country-wide networks that serve more than one million users. Interestingly, the proposed techniques can be implemented using the existing network monitoring infrastructure, specially for large networks, at a negligible additional investment.