弹性光网络中多播路由算法的研究

发布时间：2018-05-26 02:09

本文选题：弹性光网络 + 多播　；参考：《西安电子科技大学》2016年硕士论文

【摘要】：随着网络中业务量的急剧增长以及宽带业务的普及,网络中的频谱资源变得越来越宝贵,传统的波长路由全光网由于灵活性差、频谱资源浪费严重而面临严峻挑战。近些年提出的弹性光网络以灵活利用频谱为特征,通过采用以OFDM调制方式为基础的带宽可变技术,可以根据用户需要和业务量大小动态分配适量的频谱资源并配置相应的调制格式,有效克服了波长路由全光网的缺陷。同时,弹性光网络中的路由和频谱分配问题变得更加复杂。本文对弹性光网络中的多播路由算法进行了研究,所做的主要工作如下:(1)首先介绍了全光网的发展历程、弹性光网络的产生背景及技术特点,其次介绍了弹性光网络中多播技术的研究情况,并对多播技术的影响因素和主要问题进行了分析。(2)基于较优路径优先选用的思想对多播路由算法进行了研究。首先,基于对路径频谱可利用程度的评价提出了频谱连续度最大路径优先选用算法,其次,提出了多播树频谱连续度的概念,并基于这个概念提出了使多播树频谱连续度最大的路径优先选用算法,最后,从空隙频隙的角度对多播树频谱的可利用程度进行了评价,分别提出了业务相关一致空闲频隙算法和有效空闲频隙算法。对这几种算法进行了仿真,并与MPH多播路由算法进行了性能比较,结果表明,这几种算法具有良好的阻塞性能。(3)通过改变链路权值和路径权值的计算方式对Dijkstra算法进行了改进,使改进的Dijkstra算法计算出的路径的频谱有较大的可利用程度,同时保证路径不会太长。对基于改进的Dijkstra算法的多播路由算法进行了仿真和性能分析。另外,提出了基于不同路由策略再次寻路的有效路径接入算法,在多播树建立过程中因无频谱可分配而停止建树时,用改进的Dijkstra算法再次寻路,尽可能地保证多播树继续建立并最终建立成功。对提出的算法进行了仿真和性能分析。(4)对已有的基于分层策略的多播路由算法进行了改进,提出一种基于最小代价选层的多播路由算法,通过选取代价最小的多播树,可以有效节省频谱资源。仿真结果表明,该算法的阻塞性能显著提高。
[Abstract]:With the rapid growth of network traffic and the popularization of broadband services, the spectrum resources in the network become more and more valuable. The traditional wavelength routing all-optical network is faced with severe challenges because of its poor flexibility and serious waste of spectrum resources. In recent years, elastic optical networks are characterized by flexible use of spectrum, and the bandwidth variable technology based on OFDM modulation is adopted. Appropriate spectrum resources can be dynamically allocated and corresponding modulation formats can be configured according to user needs and traffic size, which effectively overcomes the defects of wavelength routing all-optical networks. At the same time, routing and spectrum allocation problems in elastic optical networks become more complex. In this paper, the multicast routing algorithm in elastic optical networks is studied. The main work is as follows: firstly, the development of all-optical networks, the background and technical characteristics of elastic optical networks are introduced. Secondly, this paper introduces the research situation of multicast technology in elastic optical networks, and analyzes the influencing factors and main problems of multicast technology. (2) based on the idea of preferred path selection, the multicast routing algorithm is studied. Firstly, based on the evaluation of the spectrum availability of the path, an algorithm of maximum path preference for spectrum continuity is proposed. Secondly, the concept of spectrum continuity of multicast tree is proposed. Based on this concept, a path preference algorithm is proposed to maximize the spectral continuity of the multicast tree. Finally, the availability of the spectrum of the multicast tree is evaluated from the point of view of the gap frequency slot. The uniform idle slot algorithm and the effective idle frequency slot algorithm are proposed respectively. These algorithms are simulated and compared with MPH multicast routing algorithm. The results show that these algorithms have good blocking performance. (3) the Dijkstra algorithm is improved by changing the calculation method of link weight and path weight. The spectrum of the path calculated by the improved Dijkstra algorithm has a greater degree of utilization, while ensuring that the path will not be too long. The multicast routing algorithm based on improved Dijkstra algorithm is simulated and its performance is analyzed. In addition, an effective path access algorithm based on different routing strategies is proposed. When the multicast tree is stopped due to no spectrum allocation, the improved Dijkstra algorithm is used to find the path again. Ensure as much as possible that the multicast tree continues to be built and eventually established successfully. Simulation and performance analysis of the proposed algorithm. (4) the existing multicast routing algorithm based on hierarchical strategy is improved, and a multicast routing algorithm based on minimum cost layer selection is proposed. By selecting the least cost multicast tree, a new multicast routing algorithm is proposed. It can save spectrum resource effectively. Simulation results show that the proposed algorithm can significantly improve the blocking performance.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN929.1

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