【作者】 张会彬；

【导师】 张杰；

【作者基本信息】 北京邮电大学 ， 电磁场与微波技术， 2011， 博士

【摘要】 随着互联网与物联网应用的高速发展,通信网络业务容量爆炸式增长,光传送技术面临越来越严峻的挑战。以OTN/PTN为代表的新一代光传送技术正在取代传统DWDM、SDH技术的统治地位,逐渐成为新一代光传送网的主流,光传送网络的大容量、分组化、智能化趋势日益明显。OTN/PTN技术标准日益成熟,组网应用大规模展开,由于节点能力约束引起的网络性能受限问题也越来越突出。针对OTN网络,主要是电交叉能力受限引起的资源预留失败问题和光交叉结构不平衡性造成的建路阻塞问题；而针对PTN网络,则主要是调度机制、资源预留和路由的协同性导致的业务QoS性能劣化问题。以这些问题为出发点,在国家863课题“新一代光网络标准、测试和组网应用研究”的支持下,本文重点研究新一代光传送网的关键技术,特别是研究OTN/PTN网络的资源优化和约束路由问题,并取得了若干具有创新性的研究成果。主要工作和创新性成果如下：第一,针对OTN多层网络中由于电交叉资源限制导致的资源预留失败问题,参考标准节点模型定义,提出了OTN电结构约束节点模型,并基于此提出了一种基于OTN节点电结构约束的动态路由优化算法。根据光层建路和电层建路的不同模式,算法分为光层建路优先、电层建路优先和光电混合算路优先三种策略,并利用OMNeT++仿真工具对三种策略进行了仿真实验。实验结果表明,相对于其他两种策略,电层建路优先策略在阻塞率性能方面具有较大优势。第二,针对OTN节点光交叉结构不平衡性造成的建路阻塞问题,研究了OTN有阻光节点的内在结构,分析了节点光结构约束模型,提出了基于OTN节点光结构约束的冲突感知波长分配算法,以有效降低网络阻塞率,并利用OMNeT++仿真工具进行了仿真实验。实验结果表明,考虑节点光结构约束后,之前广泛使用的波长分配算法的性能发生了很大异化,在所研究的网络模型中,本文提出的M&R、R&M方案的性能要优于传统方案。第三,围绕OTN多层网络节点电结构约束模型,针对OTN节点电交叉资源中LIU资源和AIU资源配比不平衡性问题,研究了骨干OTN多层网络中LIU资源和AIU资源配比关系对网络性能的影响,揭示了在流量荷载的各个阶段,LIU配置率在60%-70%的时候OTN网络性能最佳的特性,为骨干OTN网络建设提供了重要参考。并在此基础上提出了一种启发式算法来解决任意OTN网络的电交叉资源优化配置问题,并基于线性逼近策略和阻塞率逼近策略利用OMNeT++仿真工具进行了仿真实验。实验结果表明,阻塞率逼近策略相对于线性逼近策略在资源利用率方面性能有更大的提升,在满足相同阻塞率的情况下大幅降低了LIU资源的配置量。第四,MPLS-TP网络面向传送的特性使其对业务QoS的保证有更高的要求。本文针对MPLS-TP网络中调度机制、资源预留和路由的协同性问题,研究了调度机制的不公平性对业务QoS特性的影响并将这种不公平性作为重要约束引入到路由计算过程中,提出了一种基于调度机制不公平性约束的分布式路由优化算法,并利用仿真工具对算法进行了仿真实验。实验结果表明,基于调度机制不公平性约束的分布式路由算法能有效提高高等级业务的QoS特性。第五,针对传统光传送网络资源管理优化过程中存在的交互性与管控能力不足和资源配置不均衡等问题,提出了光传送网络资源管理优化平台的方案,在这个方案中论文提出了任务管理中心的架构,结合虚拟化构建了一个开放的、可重构的、交互式网络资源管理优化平台,有效解决了多方接入、数据共享与安全、统一管控和均衡资源配置等问题。在此框架内开发实现了MPLS-TP网络中同步网络规划／优化模块,移植实现了网管模块和传输仿真模块,将网络的规划优化、传输的性能分析和网管有机结合,将前台展示和后台运算实体分离,实现了数据的实时更新和资源的优化配置。更多还原

【Abstract】 The rapid growth of Internet and other data applications (such as digital video broadcasting, cloud computation, cloud storage, and so on) has become a huge challenge for the optical transport networks. Optical transport networks should be able to carry the full-service, including voice and data services, multimedia services and other business carrying requirements, providing flexible, efficient and reliable bandwidth. OTN and PTN technologies, which are replacing SDH and DWDM, are the inevitable evolution trends. Although data transport can be solved by OTN and PTN, there is still a validity requirement. Under the driven of the validity requirement, there are still a series of problems in optical transport networks, such as service complexity, routing cooperation and network efficiency. To solve these problems, this paper mainly researches on the key technologies in optical transport networks, especially the problem of routing and resource optimization, with the support by the project of the national high-tech research and development program "next generation optical network standards, testing and networking application". A number of innovative research achievements have been gained. The main contribution and innovation of this dissertation are described as follows.Firstly, in order to solve the unbalance problem caused by the structure of the OTN node, an OTN numeric model is proposed to analyze the structure constraints problem of the OTN node. Based on the numeric model above, three multi-layer traffic grooming algorithms (OC-DKI, OC-DIK and OC-DIKP) are also proposed, in which the OTN capacity constraint is taken into account. Furthermore, five wavelength assignment algorithms are also proposed. Numeric results show that OC-DKI and M&R/R&M algorithms have better performance.Secondly, based on three multi-layer traffic grooming algorithms proposed above, LIU placement problem in the backbone OTN network is simulated and analyzed. Numeric results show that the best LIU placement ratio is 60%-70%. Furthermore, two heuristic algorithms called MBPO and LAO are proposed for solving the cross-connects capacity management problem. All simulations have been done on a simulation platform implemented using disperse event simulation tool OMNeT++, and the proposed algorithm has been implemented using Perl language. Numeric results showed that the MBPO algorithm has better performance than the LAO algorithm, and the resultant scheme enables the operators to decrease the CAPEX.Thirdly, QoS sensitive routing is a very important component of traffic engineering in DiffServ MPLS-TP networks. Based on studies of characteristics of packet scheduling algorithms and the problem of unfairness when QoS routing does not consider the mix of traffic classes, a new routing scheme STE-QOSPF-Mix, which takes the reserved bandwidth supported WFQ algorithm into account, is proposed. To determine the QoS route for a flow request, STE-QOSPF-Mix considers the effective available bandwidth instead of residual bandwidth of the path, which is more suitable in DiffServ MPLS-TP networks. The simulation results show that our proposed STE-QOSPF-Mix scheme outperforms other schemes in terms of end to end delay.更多还原