Modeling and simulation of EPON with sleep mode enabled using OPNET

Passive Optical Networks (PONs) are assumed to be green access technology; however, there is still big room to maximize its energy saving. Therefore, there are significant research efforts in industries and academia. To evaluate and compare different types of energy efficiency solutions in PON, mathematical models are already studied energy efficiency. However, mathematical models are complex and require simple assumptions; so that, simulation models are preferred to obtain big picture and detailed analysis of PON. One of the widely applied approaches to make PON energy efficient is sleep mode mechanism, in which some of the components in PON equipment are turned off whenever possible. However, sleep mode could deteriorate Quality of Service (QoS) performance of PON traffic (e.g. packet might experience delay, throughput might be reduced). Therefore, it is significantly important to take into consideration these QoS factors while proposing any sleep mode algorithm. To the best of our knowledge, to date, there are a few existing research efforts to understand energy saving and TCP traffic performance in PON at the same time. In this paper, we develop a novel simulation and modeling framework for Ethernet PON (EPON) with sleep mode capability using OPNET Modular; so that, all network traffic performance could be analyzed and wide range of results could be produced. In this paper, we have analyzed the performance of TCP throughput under a very widely used sleep interval deciding algorithm used for TDM-PONs (e.g. EPON). Our findings show that depending on parameters used in sleep interval deciding algorithms and available traffic in EPON at a given time, sleep mode might affect TCP throughput remarkably.