M/M/1 model of Energy-Efficient Ethernet with byte-based coalescing

Abstract

Communication networks have been recognized as substantial energy consumer. However, the ubiquity of Ethernet links provides opportunity for energy savings with Energy-Efficient Ethernet standard and packet coalescing. So far, theoretical analysis of coalescing algorithms for Energy-Efficient Ethernet has assumed that the coalescing limit is expressed in packets; however, as Ethernet links are byte-congestible resources in nature, we argue that byte-based coalescing algorithms should be employed. To that goal, we propose an M/M/1 model for byte-based coalescing on Ethernet links compliant to Energy-Efficient Ethernet standard. The model is based on compound Poisson distribution and provides single formula for calculation of expected low-power state duration and, in turn, of energy savings. The model is applicable to 10GBASE-T Ethernet and to emerging 2.5GBASE-T and 5GBASE-T standards. Detailed simulation results show a good match of achieved energy savings to those predicted by the model. The paper discusses application of the proposed model for the evaluation of energy efficiency of 10GBASE-T Ethernet links in future IoT data centers within Smart Cities.