Finding WDM Network Topographies that are Nonblocking without Wavelength Interchange

现代长距离光网络能够承载波长的光（λ或光路）及其相关的比特流数千公里，而无需再生，从光信号到电信号的转换（OEO）。 这种长距离技术大大降低了光学系统的成本，因为OEO再生传统上是昂贵的。 它还提供了（尚未实现的）运行多种数据格式的承诺。 然而，当需要将相同波长的两个光纤插入到同一光纤上时，它们中的至少一个必须经历OEO以便改变其波长。 这被称为波长互换。 最小化波长交换的路由和波长分配（RWA）问题已经得到了深入的研究，本项目将研究一个不同的问题：什么类型的拓扑结构最小化波长交换的需要？ 这个问题预计将导致图形属性，最大限度地减少需要在物理网络中的波长交换。 通过采取不同的方法来理解波长交换的最小化，该项目将RWA问题与网络设计问题相结合。 反过来，这使得网络弹性问题与光层设计问题相结合。长距离光网络是现代经济的基本要素。 最大限度地降低网络成本以及网络的灵活性和复原力都是影响我们国家利益的问题。

Modern long-haul optical networks are capable of carrying a wavelength of light (a lambda or an optical circuit) and its associated bit stream thousands of kilometers without regeneration, conversion from an optical signal to an electrical one and back again (OEO). This long-haul technology has substantially reduced the cost of optical systems since OEO regeneration has traditionally been expensive. It has also offered the (as yet unrealized) promise of running multiple data formats. However, when two lambdas of the same wavelength need to be inserted onto the same optical fiber at least one of them must undergo OEO in order to change its wavelength. This is called wavelength interchange. The problem of routing and wavelength assignment (RWA) to minimize the number of wavelength interchanges has been deeply studied.This project will study a different question: what types of topologies minimize the need for wavelength interchange? This question is expected to lead to graph properties that minimize the need for wavelength interchange in physical networks. By taking a different approach to understanding the minimization of wavelength interchange the project couples the RWA problem to issues of network design. In turn this allows questions of network resilience to be coupled to questions of optical-layer design. Long-haul optical networks are a foundational element of the modern economy. Both network cost minimization and network flexibility and resilience are concerns affecting our national interests.