Design of Energy-Efficient EPON: A Novel Protocol Proposal and Its Performance Analysis
Economical and environmental concerns necessitate network engineers to focus on energy-efficient access network design. The optical network units (ONUs) are predominate sources of the energy consumption of Ethernet passive optical network, which motivate us toward designing a novel protocol for saving energy at ONUs. The proposed protocol exploits different low power modes (LPMs) and opts for the suitable one using traffic prediction. This scheme provides a significant improvement of energy-efficiency especially at high load (~40%) over existing ONU-assisted protocols. A better understanding of the performance and a deeper insight into several design aspects can only be addressed through a detailed mathematical analysis. The proposed protocol involves traffic prediction, which infringes the Markovian property. However, some pragmatic assumptions along with a proper selection of observation instances and state descriptions allow us to form a discrete time Markov chain (DTMC) of the proposed algorithm. Thus, the primary objective of this paper is to propose a novel scheme for achieving energy-efficiency at ONUs and mathematically analyze the performance of it with the help of a DTMC. The analysis reveals that the energy-efficiency is more sensitive to the power consumption of doze mode as compared to other LPMs. Further, the effect of sleep-to-wake-up time of all LPMs is minor.