Software Design And Implementation Of GPON-based ONU

With the rapid development of broadband networks, xDSL, mixed access, fiber access,wireless access are the main types of access network. In the field of cable access, fiberaccess gradually becomes a mainstream technology of access network due to the largebandwidth of optical fiber technology, attenuation and other advantages. Fiber to replacecopper wire is a trend. Gigabit Passive Optical Network (GPON) is an importanttechnology of the fiber access, it gets a lot of attention because of its high bandwidth, highefficiency and support full-service features.Optical Line Terminal (OLT), Optical Network Unit (ONU), Optical DistributionNetwork (ODN) are the three parts of GPON system. OLT places in the center room use,while ONU usually places on the user side. ONU is the client-oriented core unit of GPONsystem, its implementation techniques and cost directly affect the capacity of the opticalfiber users, thus OLT also affects the development and application prospects of the GPONtechnology.This paper explores the functions, working principle and key technology of eachGPON system based on studying the specification of ITU-T G.984GPON and analysingGPON network architecture and protocol hierarchy, to provide theoretical principles for thedesign of ONU. Then ONU is studied in three aspects by hardware overall framework, thefunction and structure of the main chip and the realization of the service processes, toprovide the technical basis for software design and design thinking of the ONU system. Onthe basis of theoretical principles and techniques, this work focuses on the ONU softwaredesign program and develops the software design of the ONU by analysing the ONUsoftware hierarchical layers function. The relationship between the various softwaremodules in the ONU system and the specific implementation principle and programs ofmain modules are described in detail. Finally, ONU unicast, multicast, and other basicservice functions, Quality of Service (QoS) functionality, performance statistics, and Access Control List (ACL) function are validated by experiment.