Routing, Restoration and Reconfiguration in Lightwave Networks

提出的研究目的是开发有效的解决方案，用于电路交换波分复用(WDM)网络中的光路的路由、恢复和重新配置。这样的网络对于下一代互联网的成功至关重要，下一代互联网将具有以更低的延迟承载比今天互联网大得多的流量的能力。网络层简单地使用光路作为虚拟链路，在其上执行存储转发分组路由。对光网络架构师来说，在其上进行电子分组传输的光层体系结构的设计是一个挑战。拟议的项目旨在通过提高光网络体系结构的容错性和适应性来为光层设计做出贡献。这个项目有两个主要组成部分。第一个组成部分是开发在链路发生故障时有效恢复光路的算法。这些算法不仅可以有效地利用网络资源，即波长和交换机，还可以提供快速恢复能力。这需要在资源分配时联合设计服务和恢复路径，从而减少在链路或节点故障的情况下重新路由光路所需的波长数量。研究人员将考虑基于网格的恢复算法，并从波长需求和恢复速度两个方面评估其性能。除了为每条光路确定服务和恢复路径外，路由/恢复算法还将指定有效的信令机制，以协调到恢复路径的切换和向这些路径分配波长。将分析所提出的信令机制的恢复时间和计算复杂性。基于光路的互联网主干通过改变光路集为逻辑拓扑的重新配置提供了独特的机会。这种重新配置必须基于对逻辑链路上的分组业务的实时测量，并且可以在分组网络的容量规划中提供额外的自由度。研究人员将设计用于确定拓扑重新配置的频率和性质的算法。在光层引入动态拓扑变换以满足网络层的动态业务需求是一个很有前途的概念，有望开辟许多有趣的研究方向。

The objective of the proposed research is to develop efficient solutions for routing, restoration, and reconfiguration of lightpaths in a circuit-switched wavelength division multiplexed (WDM) network. Such a network is fundamentally important to the success of a next-generation Internet which will have the capacity to carry a much larger amount of traffic than today's Internet at lower delays. The network layer simply uses the lightpaths as the virtual links over which store-and-forward packet routing is performed. The design of the optical layer architecture over which electronic packet transport takes place is a grant challenge for optical network architects. The proposed project aims to contribute to this optical layer design by improving the fault tolerance and adaptability of the optical network architecture. There are two major components to this project. The first component is to develop algorithms that efficiently restore lightpaths in the event of link failures. These algorithms will not only utilize the network resources, namely wavelengths and switches, efficiently, but also provide rapid restoration capability. This requires the design of service and restoration paths jointly at the time of resource allocation, thereby reducing the number of wavelengths required to reroute the lightpaths in the event of a link or node failure. The researchers will consider mesh-based restoration algorithms and evaluate their performance both in terms of wavelength requirement and restoration speed. In addition to determining service and restoration paths for each lightpath, the routing/restoration algorithms will also specify efficient signalling mechanisms to coordinate the switchover to the restoration paths and the allocation of wavelengths to such paths. Restoration times and the computational complexity of the proposed signalling mechanisms will be analyzed. A lightpath-based Internet backbone provides a unique opportunity for the reconfiguration of the logical topology by changing the set of lightpaths. Such reconfiguration must be based on real-time measurement of packet traffic on the logical links and can provide an additional degree of freedom in the capacity planning for packet networks. The researchers will design algorithms that will be used to determine the frequency and the nature of topology reconfiguration. The introduction of dynamic topological transformation at the optical layer to satisfy the dynamic traffic requirements at the network layer is a promising concept that is expected to open many interesting research directions.