【作者】 张笑宇；

【导师】 林金桐；

【作者基本信息】 北京邮电大学 ， 电磁场与微波技术， 2008， 硕士

【摘要】 LOBS是一种新型的光交换技术,结合了OCS与OPS的长处,并使用了MPLS技术,是当前光交换网络研究的热点。本文首先介绍了一个LOBS实验平台,并在原有平台的框架和层次结构上进行了重新设计。新加入的FPGA管理模块用于协调和优先处理包括GMPLS接口模块、MPLS控制、网管等多个应用程序的请求,并在FPGA驱动模块中进行相应的修改以支持相应的硬件读写操作。经过调整后实现了LOBS与GMPLS域的互联,并加强了系统从硬件错误恢复的能力,整体稳定性得到了提高。论文利用基于NS2的仿真平台从理论上研究了LOBS网络中RBUDP的传输性能,分析了RBUDP的传输过程并提出了LOBS网络中的RBUDP传输模型,然后针对不同的组时延、突发帧丢失率等参数,利用NS2仿真环境与LOBS实验平台进行了传输实验。仿真和实验结果表明,对不同的组帧时间门限(1ms～100ms)和长度门限(100Kbytes～500Kbytes),RBUDP吞吐量仅取决于可用带宽;并且在高组帧时延(100ms)及高突发帧丢失率(1%)情况下,保持很高的平均带宽利用率(95%)。总传输时间主要受突发帧丢失率影响,并与负荷大小近似呈线性关系。此外,针对核心节点竞争下的突发帧丢失(0.1%～1%)、不同发送速率(100Mbits/s～1Gbits/s)、负荷大小(200Mbytes～2Gbytes)的实验中,结果与理论模型误差低于2%。论文第一章首先介绍了研究背景、光突发交换原理及其关键技术,其次介绍了TCP的现状及所遇到的问题,在此基础上比较了几种常见的UDP类协议。第二章介绍基于NS2的仿真环境和LOBS实验平台,并详细介绍了后者的设计思路和系统结构。第三章介绍了RBUDP原理,分析该协议在LOBS网络中的传输模型,并给出了不同条件下的仿真及实验结果。第四章总结所做工作,并对下一步LOBS网络中传输协议研究方向提出一些观点和意见。更多还原

【Abstract】 Labeled Optical Burst Switching (LOBS), which combines the best of the OCS / OPS and takes advantage of MPLS, is a promising optical network infrastructure. It is the focus of the research of optical switching. Firstly a practical LOBS test bed is presented in this paper. The framework and the layouts of the system are redesigned. A new FPGA management module is added to handle the requests from different application modules, which include GMPLS interface, SNMP agent and MPLS control module. FPGA driver is also updated with new read/write operation. Modifications enable the system to connect with GMPLS region and to recover from hardware errors, by which global stability is improved.In this paper, the performance of RBUDP over LOBS networks is theoretically investigated based on the NS2. The principle of RBUDP is analyzed and a transmission model of RBUDP in LOBS networks is proposed. Simulations and Experiments are processed with different parameters, such as assembly parameters and burst loss probability over LOBS test bed. With different burst assembling time threshold (1ms-100ms) and burst assembling length threshold (100Kbytes -300Kbytes), the results show the throughput of RBUDP client only depends on the available bandwidth of the network. Experimental results also show RBUDP features high (95%) average utilization efficiency of bandwidth and insensitivity to large assembly delay (100ms) and high burst loss probability (1%). The total transfer time is mainly affected by the burst loss probability, and increase linearly with the payload. Under the condition of burst loss probability of 0.1%-1%, sending rate of 100Mbits/s-1Gbit/s and payload size of 200Mbytes-2Gbytes, the differences between the experimental results and the simulation results is less than 2%.The first chapter introduces the basics and the key technology of LOBS networks. Then the transmission problems of TCP over high-bandwidth network are explored. Meanwhile several UDP-based protocols are introduced and compared. The second chapter presents a simulation environment based on NS2 and a LOBS test bed. The detailed designation of the FPGA management module and FPGA driver is described. In the third chapter, the principle of RBUDP and its transmission model in LOBS networks is analyzed. The results of simulations and experiments are given out. In the last chapter, the works are summarized. Several viewpoints and ideas are proposed for the future research on transmission protocols over LOBS networks.更多还原