Improving the Cost-Effectiveness of WDM Optical Networks

这项提案是由乔治华盛顿大学和威廉玛丽学院的研究人员共同提交的。尽管有较低的误差率和更高的容量，WDM（波分复用）光网络还没有在市场上与电子网络竞争。主要原因是硬件成本过高，这使得除了少数用户外，所有人都无法接触到光网络。这里提出的研究针对这些令人望而却步的成本，旨在帮助网络设计者回答一些与尺寸和组件尺寸相关的问题，这些问题可以帮助降低硬件成本。本研究以全光电路交换多光纤波长路由环这一已被测试的技术为出发点，并提出“能否以更少的硬件获得高性能？”“虽然网络的许多方面（从可制造性到更高级的软件设计）构成了总体成本，但该项目的重点是通过限制光交换机的复杂性（交叉点）和通过时间间隔更有效地利用可用带宽来降低成本。从这些成本考虑中产生的三种类型的资源分配问题将被调查，执行资源分配的算法将被设计和评估。第一类问题涉及限制光纤对光纤交换机的灵活性，以降低制造交换机的成本。初步结果表明，即使交换机的连通性显著降低，也可以获得接近最佳的吞吐量。在这种情况下将解决的一些研究问题是：切换到光纤的限制如何在数量上改变性能？在这些限制下，波长分配是否有根本的不同？第二类问题涉及到用较小的环构造更大的网络。这个问题的研究问题包括：全光多环如何以经济有效的方式连接，特别是利用光纤交换的限制？在环间和环内会话中，波长应该如何划分（如果有的话）？第三类问题涉及到在带槽的光网络（时分多路复用）中有效地调度多速率会话。该技术的实际可行性已经得到证明。这里的重点是资源分配问题，通过更有效地利用光纤交换限制的带宽，降低总体网络成本。最后，当所有三种类型的设计特征都存在时，将采用综合方法来研究网络性能。研究结果旨在在不久的将来适用，因此最初的方法将使用模拟和建模的组合，而后来的pi将旨在对问题进行更深入的理论理解。

This proposal is a joint proposal submitted by investigators at the George Washington University and the College of William and Mary. In spite of lower error rates and far higher capacities, WDM (Wavelength Division Multiplexing) optical networks have yet to compete with their electronic counterparts in the marketplace. The main reason is the prohibitive cost of the hardware, which puts optical networks out of reach for all but a few users.The research proposed here takes aim at some of these prohibitive costs and is intended to help network designers answer some questions related to dimensioning and component-sizing that can help reduce hardware costs.The proposed research takes as a starting point an all-optical circuit-switched multifiber avelength-routing ring, a tested technology, and asks the question ``Can high performance be obtained with less hardware?'' While many aspects of a network (ranging from manufacturability to higher-level software design) make up the overall cost, this project focuses on reducing costs by limiting the complexity (crosspoints) of optical switches and from more effectively using available bandwidth by time-slotting.Three types of resource allocation problems that arise from these cost considerations will be investigated and algorithms that perform resource allocation will be designed and evaluated.The first type of problem involves limiting the flexibility of fiber-to-fiber switches in an effort to reduce the cost of manufacturing switches. Preliminary results indicate that near-optimal throughput can be obtained even with significant reduction in the connectivity of the switch. Some research questions that will be addressed in this case are: how does performance vary quantitatively with limitations in switching to fibers? does wavelength allocation differ fundamentally with these restrictions?The second type of problem involves constructing larger networks from smaller rings. Research questions for this problem include: how should all-optical multiple rings be connected in a cost-effective manner, especially by using fiber-switching limitations? how should wavelengths be partitioned (if at all) for inter-ring and intra-ring sessions?The third type of problem involves efficiently scheduling multi-rate sessions in an optical network with slots (time-division multiplexing). The practical feasibility of this technology has already been demonstrated. The focus here is on resource allocation problems that, by more effectively using bandwidth with fiber-switching limitations, reduce overall network cost.Finally, an integrative approach will be taken to study network performance when all three types of design features are present. The research results are intended to be applicable in the near future, and therefore the initial approach will use a combination of simulation and modeling, whereas later the PIs will aim for a deeper theoretical understanding of the problem.