NeTS: Small: Collaborative Research: Cross Layer Survivability to Cascading Failures in Layered Networks

WDM（波长复用）光网络是所有现代通信网络和系统的关键支柱。因此，这些网络的容错设计和运行引起了人们极大的兴趣。在过去的十年左右，有关容错、保护和恢复问题的几个基本进展已经出现在文献中。这些进步大多是在某一层失败的背景下取得的。但是，现代通信系统由通过分层协议进行通信的多个物理实现组成。因此，一层的单个故障可能导致级联故障，即物理层的故障导致逻辑层的故障。跨层生存能力这一领域的研究仍处于起步阶段。在这个基础研究项目中，主要研究人员将进行跨层网络生存能力的研究，以处理分层网络中的级联故障。该研究将在ip over wdm光网络的背景下进行。重点将放在物理层（光）中的多重故障及其在更高层（即IP层）的后果上。具体而言，项目的广泛范围将涵盖i)多种故障下的可生存逻辑拓扑映射，ii)保证生存性的逻辑拓扑映射，iii)多种约束下的逻辑拓扑映射，以及iv)跨层流的广义理论，可生存逻辑拓扑的容量和相关算法挑战。该项目旨在发展统一的理论和方法，这将使我们对跨层生存能力问题的理解取得重大进展，并为跨层设计和优化的一般领域的未来发展提供理论基础。这些理论将基于图论、数学规划（如网络阻断）和算法设计的现代进展。主要研究人员将开发基于先进数据结构和计算机算法的创新算法技术，如近似技术，以及跨层流动的广义理论，这将远远超出广泛使用的单层流动的经典理论。更广泛的影响：尽管IP-Over-WDM网络将为研究提供背景，跨层流理论和将开发的算法（特别是近似）技术将具有跨计算机科学、电子工程、图论和数学规划的多学科价值。这项研究亦具有重要的教育价值，有助培训高技能的研究人员，在资讯科技的不同范畴进行尖端科技的研究和发展。

WDM (wave-length multiplexing) Optical networks form the critical backbone of all modern communication networks and systems. Therefore, there has been a great deal of interest in the fault tolerant design and operation of these networks. In the past decade or so several fundamental advances relating to the fault tolerance, protection and restoration issues have appeared in the literature. Most of these advances have been in the context of failures in one layer. But, modern communication systems consist of multiple physical implementations communicating via layered protocols. As such, a single failure at one layer may lead to cascading failures, i.e., failures at the physical layer lead to failures at the logical layer. Research in this area of cross-layer survivability is still in its infancy. In this basic research project the principal investigators will carry out a study of network survivability across layers to deal with cascading failures in layered networks. The research will be in the context of IP-over-WDM Optical networks. The focus will be on multiple failures in the physical (optical) layer and their consequences at the higher layer, namely the IP layer. Specifically, the broad scope of the project will cover i) survivable logical topology mapping under multiple failures, ii) Logical topology mapping for guaranteed survivability, iii) Logical topology mapping under multiple constraints, and iv) A generalized theory of flows across layers, capacity of survivable logical topologies and related algorithmic challenges.The project seeks to develop unifying theories and methodologies that will make significant advances to our understanding of cross-layer survivability issues, and providing the theoretical foundation for future advances in the general area of cross-layer design and optimization. These theories will be based on modern advances in graph theory, mathematical programming (e.g., network interdiction) and algorithm design. The principal investigators will develop innovative algorithmic techniques based on advanced data structures and computer algorithms such as approximation techniques as well as a generalized theory of cross layer flows that will go well beyond the widely used classical theory of single layer flows. Broader Impact: Although IP-Over-WDM networks will provide the context for the research, the theory of cross-layer flows and the algorithmic (in particular approximation) techniques that will be developed will have multidisciplinary value spanning computer science, electrical engineering, graph theory and mathematical programming. The research will also have significant educational value in training highly skilled researchers for research and development in cutting edge technologies in different areas of information technology.