Ethernet Adaptive Link Rate: System Design and Performance Evaluation

The Internet and the devices that connect to it consume a growing and significant amount of electricity. The utilization of desktop-to-switch Ethernet links is generally very low and thus there is a potential for energy savings by using an adaptive link rate (ALR) protocol that matches link rate to utilization. In this paper, we design and evaluate a new ALR policy suitable for both bursty and smooth traffic. The policy uses output buffer thresholds and fine-grain utilization monitoring to determine when to switch link data rate. We develop a new traffic model for generating synthetic 1 and 10 Gb/s bursty traffic traces. Using this traffic model and simulation, we show that the new ALR policy is suitable for smooth traffic and also does not degrade performance for bursty traffic. Performance is measured in packet delay versus time in low (and energy saving) data rate