【作者】 尧昱；

【导师】 顾畹仪； 张永军；

【作者基本信息】 北京邮电大学 ， 电磁场与微波技术， 2010， 博士

【摘要】 随着互联网技术的蓬勃发展及宽带数据业务的爆炸式增长,传送网承载的业务正在从以TDM为主向以IP为主转变,传统的面向TDM业务的SDH传送网技术已难以满足IP化数据业务的传送需求,迫切需要一个智能的传送层面将各类业务高效、灵活地梳理到光纤巨大的带宽通道中,并保证业务的可靠性、可管理性和可扩展性。分组传送网(PTN, Packet Transport Network)正好满足了以上需求,使得TDM向分组化的平滑演进成为可能。分组传送网能够灵活智能地建立网络连接、合理高效地调度网络资源,并能提供快速、可靠的业务保护恢复手段。其中,生存性技术是保证分组传送网性能的关键技术,用于在网络发生任何故障后能尽快将受影响的业务重新倒换到备份或者空闲资源上以减少损失,其实现主要参考两方面因素——恢复时间和保护资源。本论文在国家863项目“基于T-MPLS的电信级分组传送网络”的支持下,从这两个方面对分组传送网生存性进行了深入研究,围绕资源优化的生存性技术取得了若干具有创新性的成果,主要的工作和创新点包括以下几个方面：第一,根据T-MPLS相关标准及技术原理设计了基于T-MPLS的分组传送网实验网架构,提出T-MPLS节点功能模型及多业务传送的封装/解封装解决方案,并在此基础上参与完成硬件传送平台及控制平面仿真软件,为分组传送网中各种功能及优化算法的研究提供分析验证手段。第二,等价多路径能有效地实现负载分担及流量均衡,但将引入网络管控上的困难。论文基于网络电信级的可管可控需求,分析不同的OAM功能在包含等价多路径域的分组传送网中的实现并提出相应的节点处理及帧扩展方案。笔者通过扩展OAM帧功能及节点对OAM帧的处理,在包含等价多路径的分组传送网中实现了端到端路径的OAM功能。同时提出OAM节点功能模型,通过OAM功能的实现,分析发送周期及网络拓扑等对OAM性能的影响。第三,针对快速重路由技术中用于保护的链路带宽消耗大的问题,基于共享风险链路组(SRLG)的共享保护思想,提出基于共享的资源预留及建路机制。并在此基础上,提出基于源节点计算的共享保护路由算法,以实现保护路径间资源共享最大化。另外,考虑工作路径对保护路径选择的影响,对提出的共享保护路由算法进行改进,实现工作路径与保护路径占用总资源更少。同时,考虑资源在权重中的影响比例,对链路权重进行修改,使提出的共享保护路由算法能够适应各种因素对链路权重的影响。第四,在分析分组传送网组播生存性的基础上,提出两种组播生存性技术。一种是探测重路由路径的快速组播恢复技术。该技术定义重路由探测消息,通过泛洪该消息完成重路由路径的快速寻找,实现在节约网络资源的同时尽可能缩短恢复时间。另一种是在组播快速重路由技术中,提出避免路径重复及回路的组播树保护技术。该技术通过扩展协议信令及节点处理,利用组播树中故障无关节点,以避免保护路径和组播工作路径重复或形成回路,达到减少资源浪费、实现资源优化的目的。更多还原

【Abstract】 With the rapid development of Internet technology, and the explosive growth of broadband data sevices, transfer of Service on Transport Network has happened from TDM to IP. Tranditional SDH transport network which is mainly for TDM cann’t meet the requirement of IP service’s transport. Then an intelligent transport layer is needed to pad the huge capacity of fiber with kinds of service efficiently and flexibly, and the transport layer should guarantee the reliability, manageability and expandability of service.Appearance of PTN (Packet Transport Network) transport layer meets the requirements above, and it made the smooth evolution from TDM to IP become possible. Packet Transport Network (PTN) can automatically establish dynamic traffic connections and effectively configure network resources. And also multiple schmes for rapid restoration are provided in PTN. These incredible network functions are realized due to control plane based on GMPLS. Survivability is the key technology which greatly impacts the performance of optical networks. It is used to switch the service interrupted to backup resource when fault happenes to reduce the loss of service. There are two mainly factors in survivability technology, one is protection time, and the other is protection resource. The survivability problems are investigated in depth in the above two aspects in this paper with the support of the High-Tech Research and Development Program of China. The main innovative contributions about survivability based on resource optimization are listed as follows.Firstly, According to the T-MPLS standards and theory, network architecture of Packet Transport Network (PTN) based on T-MPLS and the function of nodes are designed, including control unit, management unit and switching and forwarding unit. Adaptation and carrier of multi-service in node interfaces are researched to realize the access of multi-service. OAM function is implemented to manage and control the network and finish the functions of ring protection.Secondly, Equal cost multi path technology (ECMP) can realize load balance, but it will bring the problems of management in PTN. In the paper the carrier-grade management is considered, and OAM functions in ECMP domain are researched. OAM frames are expanded and sub-path identification is added, then the function in the source and end nodes of ECMP domain is modified, to finish end to end OAM function in the domain including ECMP.Thirdly, based on previous study, shared-bandwidth reservation and backup path establishment strategy is proposed to solve the problem of large resource consumption in fast reroute. RSVP protocol has been expanded to realize bandwidth sharing among backup paths of different service LSPs during the establishment of backup path. A routing algorithm for backup path computation and its enhancement are proposed to solve out the problem of sharing among backup paths that belong to different SRLG work paths.Fourthly, based on survivability of multicast, two aspects are researched according to the feature of multicast tree. On the one hand, protection time is considered. A restoration technology of finding backup path is proposed to reduce the protection time and speed up the protection. On the other hand, protection resource is considered. A fast reroute protection strategy of avoiding path repeat and loop is rased to implement resource optimization.更多还原