基于以太网交换机的IEEE1588V2时钟同步协议研究与实现

发布时间：2018-06-08 05:28

本文选题：时钟同步 + 交换机　；参考：《杭州电子科技大学》2014年硕士论文

【摘要】：随着通信网络的飞速发展，移动宽带业务的不断扩张，移动网络全IP化势在必行。而在对分组网络建设时，一个关键技术要求就是要实现时钟同步。在3G无线通信领域，WCDMA需要支持频率同步，而TD-SCDMA和CDMA-2000则需要在支持频率同步的基础上还需要支持时间同步。移动运营商在进行IP无线接入网(IP RAN)建设时，明确提出了在IP RAN中实现时钟同步，也就是实现IEEE1588V2的时间同步协议。以太网没有提供网络时间同步的能力，对于时间敏感的应用（如语音视频，工业自动化）和发布精确的频率参考（手机基站），这样的功能不能很好地支持。为了达到时钟同步的功能，目前主要是通过在各基站节点设备上安装GPS(Global Position System)来获取精确时间，使得各接入设备间实现时钟同步。这种实现方案系统可靠性低，结构复杂，施工难度比较大，而且很容易受到干扰等。而在下一代网络的核心交换设备以太网交换机上实现IEEE1588V2协议标准正好解决了该问题。“IEEE1588”协议的全称是网络测量和控制系统的精确时钟同步协议，通常称为精密时间协议(Precision Time Protocol，PTP)，，该协议定义了一套精确的时钟频率及绝对的时间同步机制，用于解决成本过高和精度不足等问题。本文详细介绍了IEEE1588V2时钟同步标准协议中定义的PTP时钟同步协议在以太网交换机中的实现，并介绍了该协议的模型及以太网交换机各功能模块的实现，用于替代目前使用高成本的GPS时钟同步机制。此外，还通过交换机和测试仪结合给出了组网测试结果，并做了简要分析。最后，本文还指出了该时钟同步精度的不足和改进方案。
[Abstract]:With the rapid development of communication network and the continuous expansion of mobile broadband services, it is imperative for mobile network IP. In the construction of packet networks, one of the key technical requirements is to achieve clock synchronization. In the 3G wireless communication field, WCDMA needs to support frequency synchronization, while TD-SCDMA and CDMA-2000 need to support time synchronization on the basis of frequency synchronization. In the construction of IP wireless access network (IP ran), mobile operators clearly put forward the implementation of clock synchronization in IP ran, that is, the time synchronization protocol of IEEE 1588V2. Ethernet does not provide the capability of network time synchronization. For time-sensitive applications (such as voice and video, industrial automation) and the release of accurate frequency references (mobile base stations), such functions are not well supported. In order to achieve the function of clock synchronization, at present, it is mainly by installing GPS Global position system on each base station node device to obtain accurate time, so as to realize clock synchronization among access devices. This scheme has the advantages of low reliability, complex structure, difficult construction and easy interference. The implementation of the IEEE 1588V2 protocol standard on the Ethernet switch, the core switching device of the next generation network, solves this problem. The full name of the "IEEE 1588" protocol is the precise clock synchronization protocol of the network measurement and control system. The precision time protocol, commonly known as the Precision time Protocol, defines a set of precise clock frequency and absolute time synchronization mechanisms. This paper introduces the implementation of PTP clock synchronization protocol defined in IEEE 1588V2 clock synchronization protocol in Ethernet switch. This paper also introduces the model of the protocol and the realization of each functional module of Ethernet switch, which is used to replace the current high cost GPS clock synchronization mechanism. In addition, the network test results are given through the combination of the switch and the tester, and a brief analysis is made. Finally, the paper points out the shortcomings of the clock synchronization accuracy and the improvement scheme.
【学位授予单位】：杭州电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN919.34

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