Green With Envy: Unfair Congestion Control Algorithms Can Be More Energy Efficient

Despite 40 years of active research on congestion control, there has been little or no consideration of how it impacts the energy usage of end-hosts or networking equipment. Particularly with the burgeoning energy consumption of data centers and wide-area networks, we argue that the time is ripe for the networking community to start thinking along these lines. To pave the way, we conduct lab experiments to measure the energy used by popular congestion control algorithms. We consider various aspects of congestion control and the rich research challenges that arise when we consider energy efficiency. Specifically, we find that fairness for the bandwidth allocated by congestion control can increase energy consumption by as high as 16%. We extrapolate these results to projected savings on the order of $10 million/year for large data centers.