Differentiated Reliability (DiR) in Multi-layer Optical Networks

多层光网络中的差异化可靠性 (DiR)

• 批准号: 0082085
• 负责人: Andrea Fumagalli
• 金额: $ 50.01万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0082085&HistoricalAwards=false
• 关键词: Differentiated; Reliability; DiR; Multi; layer

Current optical networks typically offer two degrees of service reliability: full (100%) protection (e.g., in presence of a single fault in the network) and no (0%) protection. This reflects the historical duality that has its roots in the once divided telephone and data environments, in which the circuit oriented service required protection, i.e., provisioning readily available spare resources to replace working resources in case of fault, while the datagram oriented service relied upon restoration, i.e., on dynamic search for and reallocation of affected resources via such actions as routing table updates. The current trend, however, is gradually driving the design of networks towards a unified solution that will support, together with the traditional voice and data services, a variety of novel multimedia applications. Evidence of this trend over the last decade is the growing importance of concepts, such Quality of Service (QoS) and Differentiated Services to provide varying levels of service performance in the same network. According to the fact that today's competitive networks can no longer provide only pure voice and datagram services, the historical duality between fully protected and unprotected (100% and 0% reliability in case of a single fault) is rapidly becoming obsolete. Modern networks can no longer limit the options of reliability only to these two extreme degrees. On the other hand, while much work is being done on QoS and Differentiated Services, surprisingly little has been discussed about and proposed for developing differentiated network reliability to accommodate this change in the way networks are designed. In this proposal, the researchers proposed to address the problem of designing cost effective multi-layer network architectures that are capable of providing various reliability degrees (as opposed to 0% and 100% only) as required by the applications. In the proposal, the concept of Differentiated Reliability (DiR) is for the first time formally introduced and applied to provide multiple reliability degrees (classes) in the same layer using a common protection mechanism, e.g., line switching or path switching. According to the DiR concept, each connection in the layer under consideration is assigned a minimum reliability degree, defined as the probability that the connection is available at any given time. The overall reliability degree chosen for a given connection is determined by the application requirements. In a multi-layer network, the lower layer can thus provide the above layers with the desired reliability degree, transparently from the actual network topology, constraints, device technology, etc. The cost of the connection depends on the chosen reliability degree, with a variety of options offered by DiR. The proposed research explores the multifaceted aspects of DiR-based design of multi-layer optical networks, with specific emphasis on the IP/WDM architecture. Optimally designing a DiR network is in general extremely complex and will require special techniques tailored to handle it with acceptable computational time. Therefore, along with research on the architecture and modeling of DiR-based networks the researchers propose a powerful novel discrete optimization paradigm to efficiently handle the difficult tasks. The optimization approach is based on adopting and adjusting the Fourier Transform technique for binary domains. This unique technique makes it possible to realize an efficient "filtering" of the complex design/optimization problem, such that the solution becomes computationally feasible, while still preserving sufficient accuracy.

当前的光网络通常提供两种程度的服务可靠性：完全（100%）保护（例如，在网络中存在单个故障时）和没有（0%）保护。这反映了历史上的双重性，这种双重性根源于曾经分开的电话和数据环境，其中面向电路的服务需要保护，即，提供容易获得的备用资源以在故障的情况下替换工作资源，而面向数据报的服务依赖于恢复，即，通过路由表更新等动作动态搜索和重新分配受影响的资源。 然而，目前的趋势是逐渐推动网络设计朝向统一的解决方案，该解决方案将支持与传统的语音和数据服务一起的各种新颖的多媒体应用。在过去十年中，这种趋势的证据是概念的重要性日益增加，例如服务质量（QoS）和区分服务，以在同一网络中提供不同级别的服务性能。根据今天的竞争性网络不再能够仅提供纯语音和数据报服务的事实，完全保护和不保护（在单一故障的情况下100%和0%可靠性）之间的历史二元性正在迅速变得过时。现代网络不能再将可靠性的选择限制在这两个极端的程度。另一方面，虽然很多工作正在做QoS和区分服务，令人惊讶的是，很少有人讨论和提出发展差异化网络的可靠性，以适应这种变化的网络设计方式。 在该提案中，研究人员提出要解决设计具有成本效益的多层网络架构的问题，这些架构能够根据应用程序的要求提供各种可靠性程度（而不是0%和100%）。在该提案中，区分可靠性（DiR）的概念首次被正式引入并应用于使用公共保护机制在同一层中提供多个可靠性程度（类别），例如，线路交换或路径交换。根据DiR概念，考虑中的层中的每个连接被分配最小可靠度，其被定义为连接在任何给定时间可用的概率。为给定连接选择的总体可靠性程度由应用要求确定。因此，在多层网络中，下层可以为上层提供所需的可靠性程度，与实际网络拓扑、约束、设备技术等透明。连接的成本取决于所选择的可靠性程度，DiR提供了各种选项。 拟议的研究探讨了基于DiR的多层光网络设计的多个方面，特别强调IP/WDM架构。优化设计DiR网络通常非常复杂，需要专门的技术来处理它，并具有可接受的计算时间。因此，沿着对基于DiR的网络的架构和建模的研究，研究人员提出了一种强大的新型离散优化范式来有效地处理困难的任务。优化方法是基于采用和调整二进制域的傅里叶变换技术。这种独特的技术使得可以实现复杂设计/优化问题的有效“过滤”，使得解决方案在计算上变得可行，同时仍然保持足够的精度。