【作者】 王伟伟；

【导师】 何荣希；

【作者基本信息】 大连海事大学 ， 通信与信息系统， 2008， 硕士

【摘要】 在IP业务的高速增长和WDM(Wavelength Division Multiplexing)技术提供超大容量带宽资源的双重刺激下,传统光网络正在朝着适于传输IP业务的新一代光网络——WDM全光网络演进。全光网络(AON,All Optical Network)采用端到端的全光通路,中间没有光电转换。全光通信网以光交换技术和波分复用传输技术为基础。目前,光交换技术包括光路交换技术、光分组交换技术和光突发交换技术三种方案。这三种方案由于目前技术上的限制或者自身的不足都不能很好的适应IP突发业务,因此,一种技术上可行且有利于现有网络平稳升级的新方案——光轨技术应运而生。如何有效地选路和分配波长(Routing and WavelengthAssignment,RWA)是光轨网络的核心问题。本文将研究光轨网络的动态RWA算法,即光轨网络的光轨和光连接的动态建立算法。光轨(Light-trail)是两个节点间建立的一条单向光通道,它允许其中间节点(在不同的时间,分时复用)用它来传输数据,因此,光轨能有效地使用光网络的带宽资源。光轨方案还具有一系列的特性和优势。在第2章中,主要介绍光轨网络的节点结构,分析光轨的建立/拆除、维护等相关的信令协议机制,为第3章和第4章提供理论基础。另外,第2章还将分析光轨方案的研究现状、不足和发展前景。由于光轨中信号的下路-继续(drop-and-continue)功能,光轨所经节点越多,信号能量损失越严重。虽然可以通过SOA(Semiconductor Optical Amplifier)进行能量补偿,每条光轨的长度仍然受到限制。光轨的长度一般可用光轨经过的物理链路数(物理跳数)描述。在第3章中,我们提出一种基于长度限制的动态光轨建立算法,通过网络仿真比较算法的阻塞率性能和长度限制对建立光轨的影响。由于在光轨网络中建立光轨存在光连接重叠现象,会造成光轨利用率下降。为了有效建立光连接,改善光连接重叠现象以提高光轨的利用率,第4章将提出一种基于优先权的动态光连接建立算法,并通过仿真研究验证算法的有效性。第5章对本文所用的仿真平台、仿真模块以及仿真伪码等进行了简要介绍。更多还原

【Abstract】 With the fast growth of IP services and the ultra large bandwidth provided by WDM (Wavelength Division Multiplexing) technology, the traditional optical network develops toward the next generation optical network-All Optical Network (AON). In AON, signals are transmitted in end-to-end all optical channels without electro-optical transformation.The AON takes the wavelength switching technology and the wavelength division multiplexing transmission technology as a foundation. At present, the wavelength switching technology have three kind of solutions which are the optical circuit swiching technology, the optical packet switching technology and the optical burst switching technology. All these technologies cannot enable IP burst service due to the limit of their technologies. Therefore, a new solution called light-trails has been proposed for catering to dynamic traffic in the optical domain. Routing and Wavelength Assignment (RWA) is one of the key problems in light-trails networks. So this paper mainly studies on dynamic RWA problem in Light-trail networks, i.e., the problem about how to create light trail and how to establish light connection dynamically.The light-trail is a unidirectional optical channel between any chosen source and destination node, which permits its middle nodes (in different time, time division multiplexing) to transmit traffic within it. Therefore, the light trail can effectively utilize the optical network’s bandwidth resources. The 2nd chapter mainly introduces the light-trial networks’s node structure, the light trail’s establishment/demolition, and the maintenance and related signaling protocols, which will provide the rationale for the 3rd chapter and the 4th chapter. Moreover, the 2nd chapter gives a brief review about the up-to-date research results about the light-trail networks.Because the light trail has the drop-and-continue functionality for the signal passing it, the signal energy loss is very serious when the signal passes through the nodes in the light trail. Although the SOA can compensate the energy which the signal loses, the light trail’s length is still restricted. The light trail’s length can be represented by the physical hop number which light trail passes. In the 3rd chapter, we propose a light trail design algorithm based on length limit. We compare the performance of the algorithm by extensive simulations and study on the influence of the light trail’s length.Although the RWA problem in WDM networks has received more attention, the current research on the light connection’s design is at the initial stage. Overlapping of light connection in the light trail has reduced the utilization rate of light trail. In the 4th chapter, we will analyze the effective design of the light connection in the light-trail networks, and propose a dynamic light connection design algorithm based on priority.Lastly, we introduce the simulation platform used in this paper, and gives the simulation modules, program pseudo codes, and so on.更多还原