【作者】 房超；

【导师】 陈雪；

【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】 随着数据业务的迅速发展,尤其是宽带、IPTV、视频等业务的出现,使得骨干传送网络不得不面对新的挑战。各个运营商的下一步发展方向是提供全业务支持能力,高效、可靠、灵活的大容量传送网将是推动未来电信技术发展的基础。因此,作为下一代传送网技术的OTN (Optical Transport Network)受到越来越多的关注。但是要具备承载多业务的能力,OTN中还有许多重要问题亟需解决,如OTN承载可变速率分组客户信号、OTN组播路由以及OTN共享网状网保护等就是其中的关键。这些关键问题的解决,将会提升OTN承载多业务的能力,大幅改善OTN的性能。因此,研究上述OTN的关键技术具有重要的现实意义。本文对上述OTN的关键技术进行了研究,论文的主要创新点和研究工作包括：1.为提高OTN承载速率可变分组客户信号的带宽利用率,提出了一种基于通用成帧规程(Generic Framing Procedure, GFP)的灵活光通道数据单元ODUflex (Optical channel Data Unit flexible)的带宽调整机制,仿真结果表明该机制能满足OTN承载速率可变分组客户信号的需要,并且能够显著地节约网络带宽。本文所设计的基于ODUflex(GFP)的带宽调整机制考虑了对未来应用的可扩展性以及实现的灵活性。经过仿真分析,当分组业务带宽变化幅度较大时,使用带宽调整机制的ODUflex连接比不使用时平均可以节约超过50%的带宽资源,而每条被ODUflex使用的高阶光通道数据单元(High Order Optical channel Data Unit, HO ODU)链路则可以平均节省14%以上的链路带宽。2.高效的OTN电层组播路由算法能有效地降低成本并提高带宽利用率,本文分别提出一种负载均衡链路共享最小代价启发式静态组播路由算法(Load-balancing Path Shared Minimum Cost Heuristic Algorithm, LPMH)和一种负载均衡时延约束最小代价启发式动态组播路由算法(Load-balancing Delay-constrained Minimum-cost Dynamic Heuristic Algorithm, LDMDH)。LPMH算法解决了经典的MPH (Minimum Path Heuristic Algorithm)算法未考虑链路共享和负载均衡的问题,适用于网络结构和组播组成员变化频率较小的准静态网络。仿真结果表明LPMH能够比MPH算法节省约5%的组播树代价,并且负载均衡度是MPH的6-8倍。LDMDH算法在满足时延约束下解决了负载均衡的问题,适用于网络结构和组播成员动态变化的网络。仿真结果表明在时延约束较低时LDMDH的组播树代价仅比MPH算法高约5%,而负载均衡度则是MPH的4倍以上。3.OTN中实现共享网状网保护能够节约网络带宽资源,论文提出了一种区分优先级负载均衡最小代价共享通道保护算法(Priority-differentiated Load-balancing Minimum Cost Shared Path Protection Algorithm, PLMC-SPP)和一种自动保护倒换(Automatic Protection Switching, APS)协议。用于OTN共享网状网保护的PLMC-SPP算法为优先级高的业务提供较短的工作和保护路由,在建立共享保护通道的同时提高了网络负载均衡。仿真结果显示PLMC-SPP在高业务强度时阻塞率比SPP算法(Shared Path Protection Algorithm, SPP)降低27%,保护资源共享度比SPP算法提高11%,网络负载均衡度是SPP的1.9倍。PLMC-SPP为高优先级业务所建工作和保护通道平均分别比低优先级的少约0.5跳和0.8跳。为推动OTN共享网状网保护机制的标准化,本文提出了OTN共享网状网保护的APS协议。通过仿真验证,OTN共享网状网保护APS协议能够在多种故障情况下完成保护倒换。更多还原

【Abstract】 With the rapid development of data services, especially the emergency of broadband, IPTV, and VOD services, the traditional transmission networks have to face new challenges. The future of operators is to provide full-service support capabilities, so the transport network of efficient, reliable and flexible high-capacity will promote the development of telecommunication. As the next generation transport technology, OTN has raised more and more concerns.However, there are many important problems havn’t be solved in OTN. For example, variable rate packet client signals over OTN, multicast routing in OTN and shared mesh protection of OTN, all of which need to enhance the capabilities of OTN. Thence, it is very important to research those key technologies for OTN. This paper has researched the above-mentioned key technologies and gained some innovative results. The main contributions of this thesis are following:1. To improve the bandwidth utilization of variable rate packet client signals over OTN, this paper proposes a mechanism to accomplish bandwidth adjustment of ODUflex(GFP), which can save considerable bandwidth by verification of simulation. The proposed bandwidth adjustment scheme considers the expandability and the flexibility of application. The simulation results demonstrate that ODUflex with the adjustment capability can save more than 50% bandwidth of ordinary ODUflex when rate variation range of packet service is large. In addition, each link used by ODUflex can save more than 14% of bandwidth.2. Electronic layer multicast of OTN can reduce costs and improve bandwidth utilization, so this paper proposes a load-balancing link-sharing minimum-cost heuristic algorithm for static multicast routing (LPMH) and a load-balancing delay-constrained minimum-cost heuristic algorithm for dynamic multicast routing (LDMDH). LPMH solve the problem of MPH that does not involve sharing of a link bandwidth and load-balancing. LPMH is suitable for the quasi-static network whose architecture and multicast group changes in low frequency. The simulation results of LPMH show that it is able to save 5% of cost than MPH, and its load-balancing degree is 6-8 times of MPH. LDMDH takes account of load balancing under delay-constraint, which is suitable for the network whose architecture and multicast group changes dynamically. The simulation results show that the tree cost of LDMDH is about 5% higher than MPH’s but its load-balancing degree is 4 times of MPH.3. The realization of OTN shared mesh protection will save network bandwidth resources, this paper puts forward a priorities-differentiated load-balancing minimum-cost shared path protection algorithm for protection routing (PLMC-SPP) and an APS protocol. PLMC-SPP provides shorter work and protection routings for the services with higher priorty, and considers the load-balancing while it constructs the shared protection path. The simulation results of PLMC-SPP show that its block probability is 27% lower than SPP’s, its shared degree of protection resource is 11% higher than SPP’s, and its load-balancing degree is 1.9 times of SPP. The work path and protection path of the service with higher priority, which are constructed by PLMC-SPP, are respectively 0.5 hops and 0.8 hops shorter than lower priority. The new APS protocol is designed to promote standardization of shared mesh protection in OTN. The simulation results of such protocol show that it can deal with the problems of multiple fault conditions.更多还原