【作者】 殷鹏程；

【导师】 谭献海；

【作者基本信息】 西南交通大学 ， 计算机应用技术， 2008， 硕士

【摘要】 随着Internet的快速发展,数据业务在骨干网上持续爆炸性增长,尤其是对IP业务的需求剧增。IP业务具有突发、多变、不确定、不可预见等特点,采用SDH、WDM技术的网络不能充分利用光纤带宽,且网络配置缓慢,操作复杂。为了适应网络发展的需求,人们将以SDH和WDM为基础的光层组网技术和以IP为基础的网络智能化技术结合起来,形成了自动交换光网络(ASON-Automatic Switched Optical Network)。ASON采用网状网的结构,引入了控制平面,提高了网络的生存性和智能性,因此ASON网络需要更加灵活、智能和高效的路由和保护恢复技术。本论文的工作围绕ASON网络的路由技术和保护恢复技术展开,主要工作及成果如下:首先,研究了ASON网络三个平面的功能、连接方式和网络模型;分析了GMPLS协议族对MPLS的扩展以及GMPLS与ASON的联系。对IP网络、SDH网络以及ASON网络的相关技术进行了分析和比较。其次,研究了ASON网络的路由模块和路由模式,对目前最常用的Bellman-Ford,Dijkstra和A-Star三种最短路径算法的性能进行了比较和分析。针对传统的路由算法的结果取决于路由业务的顺序问题,提出了一种顺序无关路由算法,使路由的结果只与网络带宽资源状态相关而与业务的路由顺序无关。新算法对需要路由的业务进行排序,然后按照最优的顺序对业务进行路由。实验证明新算法在相同的网络资源状态下能路由更多的业务,并且占用更少的带宽资源。最后,对目前ASON网络的保护机制和恢复机制进行了研究,研究了目前的保护和恢复技术,分析了保护和恢复技术的应用策略。共享风险链路组(SRLG-Shared Risk Link Group)是目前ASON网络保护恢复的标准技术,它能极大的减少工作路径和保护路径同时失效的风险。本文阐述了SRLG的概念和SRLG路径保护的原理,分析了现有的基于SRLG分离的路径保护算法,对SRLG分离的路径保护算法中常见的陷阱问题进行了研究,提出了一种新的基于陷阱发现的SRLG分离的路径保护算法。仿真表明,新算法能主动发现并绕过陷阱,降低阻塞率。更多还原

【Abstract】 With the rapid development of Internet, data traffic on backbone increases explosively, so does the demand of IP service. For the reason that IP traffic is burst, changeful, uncertain and unpredictable, the bandwidth can not be fully used in SDH or WDM optical networks, and it is hard to allocation and it is complicate to operate. To adapt the new demands of network, the optical network technology of SDH and WDM is integrated with the intelligent network technology based on IP and formed the Automatic Switched Optical Network (ASON). ASON uses mesh-network configuration, imports control panel, advances the survivability and intelligence of optical network, so ASON needs more agility, intellegent and efficient route and protection & restoration technologys.This thesis focuses on route technology and protection & restoration technology of ASON. The main works and results of this thesis are as below:First, the function of each panels, connection modes and network models of ASON are studied. GMPLS protocol’s extension of MPLS and the relationships between GMPLS and ASON are analyzed. And the relative technologys of IP network, SDH network and ASON are compared.Second, route modules and route patterns of ASON are researched, and the shortest path algorithms (Bellman-Ford, Dijkstra and A-Star) are compared and analyzed. To resolve the problem that the route results are decided by the route sequence encountered in traditional route algorithm, the thesis proposes a sequence-irrespective route algorithm. With the new algorithm, the route result is only decided by the network bandwidth status, not by the route sequence. New algorithm arranges traffics and computes routes with the best sequence. Experiment results show that this new algorithm can route more traffics and use less bindwidth resource under the same network status.Finally, the protection & restoration mechanisms of ASON are studied, the available protection & restoration technologys are discussed, and the application strategies of protection & restoration are analyzed. As a standard technology of protection & restoration, Shared Risk Link Group (SRLG) can extremely reduce the risk of both invalidity of active path and protection path. The concept and principle of path protection of SRLG are expounded, and the available SRLG-disjoint path protection algorithms are analyzed. Aimed at the common problem of "Trap" encountered in SRLG-disjoint path protection, a new SRLG-disjoint path protection algorithm based on "Trap" detection is proposed. The emulation results show that the new algorithm can detect and detour the "Traps", so as to decrease the congestion probability.更多还原