On IEEE 802.3az energy efficiency in web hosting centers

This letter presents results from our measurement campaign conducted in a web hosting center in Madrid. We collected traffic data to evaluate the potential power saving that could be achieved by replacing the company's gigabit wired links with the newly released Energy Efficient Ethernet connections (IEEE 802.3az standard). Using traffic traces collected with high precision timestamps, we feed a simulator and use an analytical model to compute the potential power saving achievable for the monitored link. We reveal that at least 80% of the power, consumed by links and network interfaces, can be saved more than 40% of the time. Furthermore, we show the importance of precise arrival time measurements by post-processing the collected traces to introduce random noise to the original timestamps. © 2012 IEEE.