Performance evaluation of energy efficient policies for ethernet switches

Energy efficiency has emerged as a defining scientific and engineering challenge of our time. Ethernet, as the dominant wireline technology, has been a focus of intense research and development efforts with the goal of significantly decreasing its energy consumption. In 2010 the IEEE Std 802.3az, which uses a Low Power Idle (LPI) mode to reduce the energy consumption of a link when there is no data traffic, was approved. Recently, the major manufacturers have brought to market the first switches the implement the new energy efficient standard. In this paper, we make use of the first generation of hardware that support the IEEE 802.3az to get a better understanding of the behavior of energy efficient mechanisms for ethernet. Based on measurement on DLINK switches that are IEEE 802.3az compliant, we build a power model that reflects more accurately the power used by real hardware in practice. We use the measurement-driven power model to analyze the behavior of Lazy Start, the state of the art algorithm for energy efficient ethernet, in the ns-3 simulator. Based on our analysis, we provide recommendations for improvements and potential directions for future work.