【作者】 陈文召；

【导师】 毛培法； 沈梁；

【作者基本信息】 浙江工业大学 ， 通信与信息系统， 2003， 硕士

【副题名】网状网故障恢复策略

【摘要】 随着社会的进步，人们对通信的需求和依赖日益增强。目前，干线传输网一般都采用SDH系统，以及承载SDH系统的WDM系统作为干线传输的主力，同时以ATM作为主要的交换平台，这使得网络的功能与业务都高度的集成化，即与以往相比，更多的业务量集中到了更少的网络元素之上。这意味着通信网，尤其是大容量的高速通信网的失效(包括节点和线路的失效)将会给人们带来巨大的经济损失；另外，随着人们生活水平的提高，人们对信息传送的质量的要求也越来越高，这使得通信网的生存策略研究显得很迫切；况且，中国已加入WTO，电信运营的竞争日趋激烈，为了在竞争中有一席之地，各电信运营商必需提供高质量、低成本的电信服务，这进一步促使通信网的生存策略研究提上日程。 通信网生存策略的研究，在国外始于1987年。我国在这个领域的研究起步较晚，90年代，国内的一些研究机构开始了对网络生存性问题的研究，但研究力量不足，这几年有明显改善。 本文主要研究了关于宽带传输网的生存性的一些问题，具体涉及网络物理拓扑生存性衡量指标、分布式自愈机制二次函数评估法、基于嵌入式信令的多线路失效恢复机制等三方面的内容。 在介绍了相关概念和回顾现有技术的基础上，从实际网络中的业务需求分布的角度，提出了一个可以用来衡量一个网络物理拓扑的生存性性能的指标——网络业务路由分布特性。该指标考虑到了网络中的具体业务需求分布情况，反映了网络需求节点对之间路由的分散特性，因此它比传统的网络连接度指标，更准确的体现了网络拓扑的生存性性能； 在分布式自愈机制的研究中，提出了一种改进的函数评估法，简称为二次函数评估法。该算法利用网络节点的先验网络拓扑知识和在恢复过程中积累起来的网络状态信息，两次构造消息评估函数以丢弃无用的消息包。同时以时钟驱动的方式驱动网络中各参与恢复进程的节点发送消息包，以确保所形成的恢复路由集合为KSP集合。另外在选择端采用简单的路由选择机制，避免了传统算法的多次消息广播的过程。计算机仿真表明，所提改进算法的恢复率和恢复速度都优于传统算法，比改进前的一次函数评估法也有所改善，尤其是在恢复过程中的消息数，得到了进一步的削减。 在考虑多线路失效的情况下，本文从理论上描述了预定模式下的带宽容量的浙江工业大学硕士学位论文一宽带传输网的生存策略研究分配方案:另外提出了基于嵌入式信令的恢复机制。该机制要求，在各节点对之间传送的消息包中，用固定的物理字段来传送网络的恢复控制消息。其缺点是，要有一个较为复杂的标准化过程;优点是，可以避免一些诸如排队延迟、网络拥塞等的常见网络问题。更多还原

【Abstract】 With the improvement of society, it becomes strong that people can’t live without telecommunication. At present, the backbone transport network in China mainly introduced the SDH transport techniques and ATM switching techniques, then the network functions and traffics are highly integrated. And the damage of transport link and/or node failures will become much more serious than that of existing networks. In addition, because of the increasing social dependence on communication systems and the growing importance of information, it is very important to study network survivability strategies, which is also one of the important criterions to evaluate transport networks.The studies of restoration strategies of transport networks have been concerned since 1987 internationally. In China, the research of this field began recently but great progress has been made. In this paper, a study of some problems in broadband transport network is conducted.On the basis of some conceptions relating to network and a brief survey of existing self-healing techniques, A norm named "the distributed character of traffic routes" is presented, which is used to judge that the survivability of a physical topology is good or not.On the research of the distributed self-healing techniques, An improved algorithm named "Function Evaluation Algorithm of 2-time" is proposed. By usingthe priori knowledge of network topology in nodes and the status information cumulated in the restoration processing, two evaluating function are constructed for every message, and the useless messages are thus discarded as fast as possible through computing these functions. Meanwhile the restoration processing in the nodes is drived by fixed clock-period. Then, by introducing a simple route selecting algorithm in chooser, a capacity-consistent restoration path set in one flooding wave can be obtained, so avoiding the multiple flooding waves in conventional algorithms. Thecomputer simulation shows that the proposed algorithm is better in both restoration ratio and restoration speed than the existed conventional ones. In the quantity of message during restoration processing, the improved algorithm is also better than the old one.This paper provides a scheme of distributing capacity resource under preplanned mode in theory in case of multi-link failure. In addition, a restoration technique based on embedding signaling also is proposed in this part. The lacks of this restoration technique is needing a complicated standard processing, and the advantages are that some normal network problems could be avoided, such as queuing delay and network congestion et al.更多还原