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.