Improving the Energy Efficiency of IEEE 802.3az EEE and Periodically Paused Switched Ethernet

It is estimated that networked devices consumed about 150 TWh of electricity in 2006 in the U.S. which has cost around $15 billion and contributed about 225 billion lbs of CO 2 to greenhouse gas emissions. About 13.5% of this energy is consumed by network equipment such as switches and routers. This thesis addresses the energy consumption of Ethernet, and designs and evaluates improvements on existing methods to reduce the energy consumption of Ethernet links and switches. Energy Efficient Ethernet (EEE) is an emerging IEEE 802.3 standard which allows Ethernet links to sleep when idle. In this thesis, a performance evaluation of EEE is completed. This evaluation replicates previous work by Reviriego et al. in an independent manner. The performance evaluation shows that EEE overhead results in less energy savings than expected. A new method based on Packet Coalescing is developed and evaluated to improve the energy efficiency of EEE. Packet Coalescing bursts packets such that EEE overhead is minimized. The results show that EEE with Packet Coalescing for 10 Gb/s Ethernet can achieve very close to ideal (or energy proportional) performance at the expense of an insignificant added per packet delay. Periodically Paused Switched Ethernet (PPSE) was previously proposed and prototyped by Blanquicet and Christensen in 2008. PPSE uses periodically sent notification packets to halt packet transmission into a LAN Switch and thus allowing the switch to sleep periodically. In this thesis, a first performance evaluation of PPSE is completed. The evaluation in this thesis shows that a PPSE for 10 Gb/s Ethernet LAN Switches achieves either significant energy savings at the expense of an excessive packet delay, or less than expected savings with a less than human response time added per-packet delay. An improvement to PPSE (Adaptive PPSE) is proposed and developed based on an adaptive policy. The adaptive policy considers past traffic load to determine whether to put the switch to sleep or not. The evaluation shows that Adaptive PPSE can achieve very close to ideal performance at the expense of an added average per packet delay which is less than half of the human response time