Adaptive Frame Coalescing in Energy Efficient Ethernet with Model Predictive Control and Queuing Theory

Abstract

Frame coalescing is a well-established technique which manages the low power idle (LPI) mode supported by energy efficient Ethernet (EEE) interfaces. Generally, this technique enables EEE interfaces to remain in the LPI mode for a certain amount of time upon the arrival of the first frame (timer-based coalescing), or until a predefined amount of traffic accumulates in the transmission buffer (size-based coalescing). In this paper, we propose a novel open-loop dynamic coalescing technique that is based on model predictive control (MPC) and queuing theory. In contrast with the conventional timer-based coalescing, the proposed method enables the update of the timer parameter repeatedly throughout the duration of the LPI mode of a single coalescing cycle by taking into account the arrival instant and size of the frames waiting in the buffer. Two different methods, namely MPC-mean and MPC-tail, are proposed which attempt to minimize the energy consumption of the Ethernet link under constraints on mean and tail of the queue waiting time, respectively. The effectiveness of the proposed dynamic MPCbased coalescing algorithms are validated using simulations with synthetic and actual traffic traces.