【作者】 罗任翔；

【导师】 刘伟平；

【作者基本信息】 暨南大学 ， 通信与信息系统， 2005， 硕士

【摘要】 以太无源光网络(EPON)是实现宽带、多业务综合接入的最佳技术之一。本文对以太无源光网络的OAM子层功能进行深入的分析、硬件实现研究以及EPONOAM应用研究。 本文首先系统分析和总结了接入网的现状及发展趋势,分别对EPON系统的构成、工作原理及技术的优势进行了系统介绍和研究,对EPON的协议分层结构进行了全面深入的分析。 本文以IEEE批准的802.3ah EPON协议为参考,详细介绍了EPON OAM子层协议及其主要功能。包括EPON系统的远端故障指示、链路监控及回环测试。其中在EPON OAM协议研究中详细阐述了定义的OAM Discovery过程、OAM协议数据单元格式等内容。 针对EPON OAM子层的功能要求,本文依据协议提出的功能实现总体框架所划分的三大功能模块即Parser、Control、Multiplexer的功能要求,在对每一模块要完成的工作进行详细分析的基础上,结合基于VHDL语言的FPGA特点,设计出各个功能模块的实现流程图,在此基础上,以VHDL语言为工具,采用Xilinx公司的ISE5.1开发环境,进行EDA设计研究,设计了每一模块的外部电路接口图,得到这三个功能模块软件设计通过的仿真结果图,从仿真图上来看,完全实现了各模块功能设计的要求。在Multiplexer功能模块研究实现中,对来自Control模块的OAMPDU数据、MAC Client数据和Loopback数据等三种不同优先级的数据采用了中断优先级处理的关键技术进行输出处理,实现了功能设计的要求。该EPON OAM子层功能实现研究为下一步具自主知识产权的支持OAM协议的EPON MAC芯片的开发奠定了坚实的基础,并对EPON系统设备深入研究提供了有价值的参考。 最后研究了EPON OAM子层协议在基于SNMP的EPON网络管理中的应用,设计利用在EPON OLT内设置的Proxy Agent(代理的代理),作为SNMP网管系统和ONU之间的通信翻译装置,以获取网络设备的各种信息。设计了Proxy Agent功能实现流程图,及设计应用Proxy Agent作为ONU设备管理信息的代理来实现SNMP对EPON网元的管理方案。另一方面,对OAM在EPON系统组播的应用进行研究,讨论设计了在现有的EPON系统中实现组播传输的方案,包括提出组播过滤的基本方案,和应用扩展定义的OAMPDU来实现OLT组播的管理。组播技术的引入,可以大大提高EPON系统对多媒体业务的支持能力。 本论文的研究对下一步EPON芯片、设备及网络管理系统的开发和EPON系统新功能的拓展有一定的参考价值。更多还原

【Abstract】 EPON is one of the best technologies to realize broadband access and multi-service access in future. In this article, OAM, the sub-layer of EPON, is deeply analyzed in the terms of functions, hardware realizing and applications.As the beginning of this article, the present situation of access network and its development trend in future are analyzed and concluded, and separately, the structure, working principle of EPON and its advantages are introduced. Specially, the hierarchical structure of EPON is explained and analyzed deeply.Taken IEEE 802.3ah protocol as the reference, which is the standard protocol of EPON, the OAM sub-layer protocol and its main functions are introduced in detail, which including remote trouble indicating, link detecting and full circle testing. Specially, the OAM Discovery procedure and the data unit format of OAM protocol is explained in detail.According to the three function modules divided in the general function-realizing frame in the protocol, which are Parser, Control, Multiplexer, the working flow chart of each function module is designed. And based on this, the external circuit interface of each module is coding in VHDL language and designed by ISE5.1 tools of Xilinx company. Seen from the simulating charts of these function modules, the aim of the design is reached very well. Interrupt request level is adopted in Multiplexer function module, that is processing and inputting the OAMPDU data, MAC Client data and Loopback data sending from Control module in three different interrupt request level. The research on EPON OAM sub-layer’s functions ensures further development of EPON MAC chipset with our own property right, and is of reference value for the researches on EPON devices.In the end of the article, the application of EPON OAM sub-layer protocol in EPON management base in SNMP is discussed. A Proxy Agent is set in EPON OLT to translate communications between SNMP management system and ONU. As a result, SNMP management system can get all the information of network devices. The function realizing flow chart of Proxy Agent is designed as follows. Using Proxy Agent as the agent of ONU management can realize a SNMP management to each EPON unit.on the other hand, The application of OAM in EPON multicast is discussed. A scheme of realizing multicast in EPON is designed, including multicast filtering scheme and using extension defined OAMPDU to realizing multicast management of OLT. Introducing multicast can make EPON more capable of supporting multimedia services.This article is of reference value for further development of EPON chipset, EPON devices or network management system and as well as the new functions of EPON.更多还原