【作者】 倪文达；

【导师】 李艳和；

【作者基本信息】 清华大学 ， 电子科学与技术， 2010， 博士

【摘要】 骨干网正向着IP over WDM的两层结构演进，其中，WDM层广泛应用基于线路交换的大容量智能光网络并向着突发交换的交换模式探索。在这一发展趋势的引领下，围绕着资源利用与服务质量的矛盾对立关系，论文从资源优化和服务质量两个角度对智能光网络演进过程中所面临的两大关键问题——线路交换光网络的生存问题及突发交换光网络的路由问题开展了基础研究。针对提供专用路径保护和共享路径保护服务的恢复时间区分光网络，论文提出了不影响连接恢复时间(单链路战障下)的资源优化供给机制。数值结果表明，与传统供给机制相比，资源优化供给机制显著降低了两种保护类型的阻塞率(专用保护>20％；共享保护>40％)和网络的总体资源冗余(>25％)。论文将备用路径再优化机制应用于共享路径保护光网络的网络工程问题中，对于预约业务，周期性的保护路径调整有效地降低了网络的平均备用容量消耗。对于半动态业务，通过对高等级连接请求引入考虑重路由保护路径灵活度的后路径计算过程，实现了两等级连接请求之间阻塞率区分的光路供给。作为对“备用路径再指配如何定量地影响连接可用率?”问题的首次探索，论文通过汁算机模拟定量地评估了备用路径再指配光网络的连接可用率。数值结果表明，带启动故障驱动备用路径再指配的共享路径保护降低了连接的不可用率，而当网络中具有充足的可用波长时，运用任意故障及修复事件驱动的备用路径再指配实现非返回的共享路径保护将具有吸引力。在IP over全光透明网络中，论文提出了一种新的生存映射机制，即在寻找生存光路时，最大化光路的物理层战障定位潜能。数值结果表明，新生存映射实现了准确或近乎准确的单链路故障定位。在基于偏置时间的丢包率区分突发交换光网络中，论文提出了等级感知路由，在不引入突发包再序的前提下实现业务分叉以降低突发包丢包率。数值结果表明，与传统等级遗忘路由相比，等级感知路由进一步降低了各等级突发包的丢包率，特别足当网络处于轻负载或中负载时。更多还原

【Abstract】 Backbone transport networks are evolving into a two-layer architecture of IP overWDM networks. In the WDM layer, circuit-switching-based intelligent optical net-works are/will be widely deployed, with the optical burst switching envisioned as apromising switching paradigm for future WDM networks. To catch up with this trend,this dissertation studies from the resource optimization perspective and the service per-spective two key issues during the architecture migration, i.e., survivability of opticalcircuit switching networks and routing in optical burst switching networks.In recovery-time-di?erentiated optical networks employing dedicated path pro-tection and shared path protection, resource-e?cient provisioning scheme is proposedwithout deteriorating the recovery time of either protection type (in the predominantsingle link failure scenarios). Numerical results show that compared with traditionalscheme, resource-e?cient provisioning scheme reduces the blocking probability ofboth protection types as well as the overall resource overbuild of the network.Next, backup path reoptimization scheme is applied to the network engineering(NE) problems in shared-path-protected optical networks. For scheduled tra?c, peri-odic rearrangement of protection paths reduces the average spare capacity consumptionof the network. For semi-dynamic tra?c, blocking-di?erentiated lightpath provision-ing between two classes of connection requests is achieved by introducing the proposedpost path calculation process for high-class requests, during which the ?exibility ofrerouting backup paths is considered.As a first attempt to address the problem of“how does backup path reprovision-ing a?ect connection availability?”, this dissertation quantitatively evaluates the con-nection availability in a network employing backup path reprovisioning. Numericalresults show that shared path protection with startup-failure-driven backup path re-provisioning reduces connection unavailability. Moreover, results show that arbitraryfailure-arrival-and-failure-repair-events-driven backup path reprovisioning is an attrac- tive approach for non-revertive operations of shared-path-protected connections whensucient free wavelengths are available in the networks.In IP over all-optical transparent networks, a new survivable mapping problemis proposed that the physical-layer failure-localization potential is maximized in find-ing the survivable mapped lightpaths. Numerical results show that accurate or near-accurate failure localizations are achieved with the new survivable mapping design.In oset-time-based loss-di?erentiated optical burst switching networks, a class-aware routing scheme is proposed to reduce the burst loss probability by splitting traf-fic while avoiding the introduction of burst reordering mechanism. Numerical resultsshow that compared with traditional class-oblivious routing, class-aware routing fur-ther reduces the burst loss probability of multiple classes especially when the networkload is light or moderate.更多还原