The low power idle mode implemented by Energy Efficient Ethernet (EEE) allows network interfaces to save up to 90% of their nominal energy consumption when idling. There is an ample body of research that recommends the use of frame coalescing algorithms—that enter the low power mode as soon as there is no more traffic waiting to be sent, and delay the exit from this mode until there is an acceptable amount of traffic queued—to minimize energy usage while maintaining an acceptable performance. However, EEE capable hardware from several manufactures delays the entrance to the low power mode for a considerable amount of time (hysteresis). In this paper we augment existing EEE energy models to account for the hysteresis delay and show that, using the configuration ranges provided by manufacturers, most existing EEE networking devices are unable to obtain significant energy savings. To improve their energy efficiency, we propose to implement frame coalescing directly at traffic sources, before reaching the network interface. We also derive the optimum coalescing parameters to obtain a given target energy consumption at the EEE device when its configuration parameters are known in advance.

节能以太网（EEE）实现的低功耗空闲模式使网络接口在空闲时最多可节省其标称能耗的90％。有大量的研究建议使用帧合并算法-一旦没有更多的流量等待发送，便进入低功耗模式，并延迟退出该模式，直到有可接受的流量为止排队—在保持可接受的性能的同时，最大程度地减少能耗。但是，来自多个制造商的具有EEE功能的硬件将进入低功耗模式的时间延迟了很长时间（磁滞）。在本文中，我们扩充了现有的EEE能量模型，以解决滞后延迟问题，并表明，使用制造商提供的配置范围，现有的大多数EEE网络设备都无法节省大量能源。为了提高其能效，我们建议在到达网络接口之前直接在流量源处实现帧合并。当预先知道其配置参数时，我们还可以得出最佳合并参数，以在EEE设备上获得给定的目标能耗。