【作者】 陈祖平；

【导师】 朱娜；

【作者基本信息】 江苏大学 ， 计算机应用技术， 2009， 硕士

【摘要】 随着光通信技术的飞速发展,光网络向着大规模、复杂拓扑、面向业务的智能化网络方向发展,对网络的生存性提出了更高的要求。为了定义网络的管理边界、提高路由和信令的性能、提高网络的可靠性,可扩展性和安全性以及兼容不同系统间的技术差异,以ASON为代表的下一代光网络将被划分为多个路由域,采用分布式管理和分层的网络路由体系。为保证网络的可扩展性,各路由域的详细拓扑信息在域内散发,路由域间只交换汇聚后的拓扑信息。因此,网络节点不具有整网的详细拓扑及配置信息,如何在缺乏全局信息的条件下提供可靠的业务连接,提高网络抵制故障业务中断或干扰的能力是网络分域带来的一个新的且重要的研究课题。论文介绍了多域分层ASON体系结构和其路由技术,分析了光网络的生存性,并着重研究了多域分层ASON生存性的特点和当前研究现状。论文提出了一种新的混合分级计算共享子路径保护算法,对算法进行了数学描述,并详细介绍了其执行步骤和信令流程。最后在流行开源网络模拟器NS上编程实现了多域分层ASON仿真平台,并基于仿真平台对算法进行仿真测试和改进。论文的主要研究内容有:(1)分析多域分层ASON的路由机制,包括分层路由体系,路由方式和路由信令过程,并对其关键技术如路由信息的汇聚,路由信息的交换和更新,路由的计算进行了研究。(2)对多域分层ASON生存性策略进行了详细探讨。介绍了现有的网络生存性和ASON的生存性,研究了多域分层ASON在路由计算,保护恢复方式和故障处理等方面的特点,并分析比较了现有多域分层ASON生存性策略。(3)提出了一种混合分级计算共享子路径保护算法。算法在上层路由域中,分别为新业务计算出工作路径和保护路径。对于工作路径在下层路由域采取“按域分段,域内保护”的方式进行保护,对于恢复路径则采取“域间保护,域内恢复”策略。算法采用域平均最短路径长度和域平均资源利用率作为虚链路的代价权重因子,对虚链路的消耗进行了较为准确的估算。仿真结果表明,算法具有较快的保护倒换速度和较好的资源利用效率,对域内链路故障和域间链路故障都有较好的故障恢复性能。(4)编程实现了基于NS的多域分层ASON仿真平台。在仿真平台中实现了多域分层ASON体系,包括信令机制,连接建立过程,路由计算过程,路由信息的汇聚和更新。为了便于比较分析,仿真平台实现了两种故障恢复方式,一种是基于本文提出的链路权重分级计算共享子路径保护算法,另一种是基于路径保护,并对两种保护算法各种性能进行分析比较。更多还原

【Abstract】 With the rapid development of Optical communication technology, optical network develop toward the large-scale,complex topologies,the intelligent network of business-oriented direction,which demand higher and higher on network survivability.The next generation optical network will be divided into multiple routing domains to improve the performance of routing and signaling,network reliability,scalability and security.It will be essential to define the border of network management and to adopt the technology of distributed management and hierarchical routing. To ensure the network scalability,the detailed information of the connection and bandwidth allocation in one domain will be limited to itself,and only aggregated information will be exposed to the external domains.As a result,no node in the multi-domains has the global information about the whole multi-domain network.In such circumstance, how to provide reliable connections to the traffic and improve the reliability are crucial to the operation of multi-domain network.At first,this article introduces the multi-domain ASON hierarchical network architecture and its routing system,then the survival technology of traditional optical network and the survival of ASON is analyzed, what’s more the existing optical multi-domain hierarchical survival techniques is studied,lastly a new Compound layered sub-path share protection algorithm which is based on existing multi-domain optical network protection algorithm is put forward.This paper also does a detailed mathematical analysis for the algorithm theory and describes signaling process of the algorithm particular.At last,through the programming expansion of open source network simulator,a multi-domain hierarchical ASON simulation platform is realized and some improvements about algorithm strategy is achieved through simulation testing(1) ASON multi-domain hierarchical network structure is described cleared,which focused on multi-domain ASON hierarchical network topology and routing calculation process,what’s more,some of the key issues of multi-domain layered ASON is discussed in detail,such as the aggregation of routing information,the exchange of routing information and the update of routing information.(2) The survival of the existing network technologies is discussed in detail and the advantages and disadvantages of a variety of network survival mechanisms is analyzed cleared.What is more the characteristics of ASON survival technology and multi-domain hierarchical network survival technology is analyzed cleared.(3) Based on the existing hierarchical ASON multi-domain survival strategy,a new mixed-grade protection of shared sub-path algorithm is put forward.This algorithm computes two paths which are work path and protection path at the upper domain routing for operation.It use "segment by sub-domain,inner domain protection" to provide protection for work path,but to restoration path it use "protection between domains, restoration in inner domains" type to provide protection.Algorithm uses the average shortest path length of the domain and domain average resource utilization for the cost of virtual link weight factor,which estimate he cost of virtual link accurately.Simulation results show that the algorithm has a faster switching speed and better resource utilization efficiency,it provide good recovery performance for inter-domain and inner domain link failures.(4) Multi-domain ASON hierarchical simulation platform which in based NS is realized by programming,multi-domain hierarchical ASON is achieved in the simulation platform,what’s more,the signaling mechanism for connection establishment process,the aggregation and update of routing information is include in the simulation platform too.In order to compare,two Recovery approach is put forward,the one is mixed-grade protection of shared sub-path protection algorithm,the other one is path protection.A comparison of performances between two algorithms is performed.更多还原