Mathematical analysis of burst transmission scheme for IEEE 802.3az energy efficient Ethernet

Abstract

The IEEE P802.3az Energy Efficient Ethernet (EEE) protocol specifies a Low Power Idle (LPI) mode in which Ethernet device can save energy by turning off components when its queue is empty, and defines a scheme for coordinating the transitions between the LPI and active modes. Depending on when Ethernet devices enter and exit the LPI mode, two schemes have been proposed: the frame transmission scheme and the burst transmission scheme. P. Reviriego et al. proposed the burst transmission scheme (the same as the packet coalescing scheme by Christensen et al.) where the link becomes active when either a fixed number of packets have arrived or a fixed time is passed from the epoch that the first packet has arrived. They showed by simulation that the burst transmission scheme has significantly lower energy consumption than the frame transmission scheme of EEE. In this paper, we provide an analytic model of the burst transmission scheme and obtain its energy consumption and packet delay. Our analytic results match the simulation results. In numerical results, we find the maximal timer which minimizes the energy consumption while satisfying the maximal packet delay within a pre-determined level.