NS Based Modeling And Performance Analysis Of Ethernet Over Passive Optical Network

The evolution of computer networks has recently become more and more rapidly. Core backbone networks have reached a very high bandwidth, so does QoS(Quality of Service). But user access network in the meantime presents as a bottleneck. Passive Optical Networks(PON) can solve the bandwidth and QoS problem. FTTH comes to be Telecom Company's best solution to both high bandwidth and high performance QoS. Much has been done in FTTH academically and preliminary attempts in its commercialization.There are several kinds of PONs, among which EPON and GPON are the most popular. EPON devices are less expensive than GPON, but pre-distribution of EPON is less high than GPON. Bandwidth and QoS of EPON is also promising. EPON has a brighter market future than GPON, and seems to prevail in dense user area.In order to optimize EPON system to reduce prophase investment, we studied NS, having made a simulation platform of EPON in NS for researchers to investigate their performance as a function of different algorithms. Before the work shown in the paper, many researchers have to spend a significant amount of time building a model of EPON system on one platform or another, however, this thesis provides an EPON model named EPONns, offering an open source model based on NS software, and it is hoped that it will provide researchers with great convenience.This thesis begins from NS, followed with a study on IEEE 802.3ah protocol. EPONns designs a complete EPON structure, and builds every object with details. Each object has different schemes, and a particular algorithm is applied to various objects, which finally are integrated to a complete system.The thesis also analyzed Ethernet traffic using Pareto heavy-tailed distribution ON/OFF traffic. EPONns simulates a long range dependence of self-similar traffic, and demonstrated a successful Ethernet traffic simulation. Using queue management, the simulation platform manages the buffer of ONU and OLT, applying Random Early Detection algorithm to solve the traffic congestion of Ethernet.In conclusion, this thesis creates the EPONns model in NS, and supplied many experiments to validate the EPONns model with validity and eifectiveness, making great effort in both theoretical study and practical system analysis in EPON.