A simple WDM Add-Drop Multiplexer (ADM) Consisting of a set of Er-doped fibers (EDF) and a shared pump is proposed. The chief benefit of the module is that the interchannel power spread does not accumulate from stage ...A simple WDM Add-Drop Multiplexer (ADM) Consisting of a set of Er-doped fibers (EDF) and a shared pump is proposed. The chief benefit of the module is that the interchannel power spread does not accumulate from stage to stage in a cascaded WDM system. Moreover, the power differences caused by different component losses existing in the WDM networks can be automatically compressed. The cost will not increase a lot since the pump source is shared in the module. The performance of a cascaded system constructed from the modules has been carefully studied by computer simulation.展开更多
IP over WDM is being envisioned as one of the most attractive architectures for the next generation Internet. This paper introduces two novel backbone node structures for IP over WDM networks. These node structures ca...IP over WDM is being envisioned as one of the most attractive architectures for the next generation Internet. This paper introduces two novel backbone node structures for IP over WDM networks. These node structures can be used as improvement approaches to DPDP (default path and dedicated path) method. The flow classifiers, which are the main components of these node structures, and the performance metrics of these structures, are also discussed.展开更多
Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is no...Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as 'mixture' of WR and OBS. We believe the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, efficiency and etc. simultaneously. However, many related problems still need to be further researched.展开更多
针对容量有限的透明IP over WDM网络模型,该文提出一种基于路径的整数线性规划(ILP)方法来优化网络的能耗。相对基于连接的整数线性规划方法,该方法可以在光层提供更多的路径选择组合。仿真结果显示,基于路径的整数线性规划方法能够通...针对容量有限的透明IP over WDM网络模型,该文提出一种基于路径的整数线性规划(ILP)方法来优化网络的能耗。相对基于连接的整数线性规划方法,该方法可以在光层提供更多的路径选择组合。仿真结果显示,基于路径的整数线性规划方法能够通过选择更优的光路组合进一步降低网络的能耗。展开更多
对IP over WDM的虚拓扑设计算法进行了研究,选择网络整体流量的均衡性作为优化目标,提出了一种新型的虚拓扑构造算法。在算法中,选择负载分布方差作为评价流量均衡性的指标,并给出其定义和计算方法。主要针对拥塞概率性能,在光层和IP层...对IP over WDM的虚拓扑设计算法进行了研究,选择网络整体流量的均衡性作为优化目标,提出了一种新型的虚拓扑构造算法。在算法中,选择负载分布方差作为评价流量均衡性的指标,并给出其定义和计算方法。主要针对拥塞概率性能,在光层和IP层将提出的新型虚拓扑构造算法与其他算法进行比较。在光层的算法比较部分,选择负载均衡启发式路由算法(RLBH,routing with load balancing heuristics)与提出的算法进行比较;在IP层的算法比较部分,选择固定路径最小拥塞路由算法(FPLC,fixed-path least-congestion)与提出的算法进行比较,并对比较结果进行了讨论。比较结果显示在拥塞概率性能方面,提出的新型虚拓扑构造算法优于RLBH算法和FPLC算法。展开更多
讨论了在IP over WDM directly分层结构下,IP层网络与光层网络的三种基本融合方式—静态重叠模型、动态重叠模型和动态对等模型,这三种融合方式体现了IP over WDM directly的演变过程。同时还对各种融合方式中网络的组成结构及相应的控...讨论了在IP over WDM directly分层结构下,IP层网络与光层网络的三种基本融合方式—静态重叠模型、动态重叠模型和动态对等模型,这三种融合方式体现了IP over WDM directly的演变过程。同时还对各种融合方式中网络的组成结构及相应的控制平面技术作了详尽的阐述。展开更多
为了优化利用IP层和WDM层网络资源,在WDM网络集成辅助图模型的基础上,提出了一种面向IP/GMPLS over WDM网络的基于代价的优化综合路由算法,即CIR(Cost-based Integrated Routing)。该算法将IP层和WDM层资源可用信息以代价函数形式给出,...为了优化利用IP层和WDM层网络资源,在WDM网络集成辅助图模型的基础上,提出了一种面向IP/GMPLS over WDM网络的基于代价的优化综合路由算法,即CIR(Cost-based Integrated Routing)。该算法将IP层和WDM层资源可用信息以代价函数形式给出,并将因网络拓扑结构和网络负载分布不均衡等产生的瓶颈链路以及带宽碎片问题也统一纳入考虑,由此将LSP建立问题转化为在集成辅助图上找出一条源、目的节点之间的最短通路问题。仿真结果表明:CIR算法有效地实现了IP和WDM两层资源的联合优化,提高了网络资源利用,降低了网络阻塞率。展开更多
IP over WDM网络是下一代网络的核心,生存性则是保证服务质量(QoS的关键要素。当网络中出现故障时,选择在IP层还是光层进行保护和恢复是非常重要的课题。文章在论述IP层和光层的保护和恢复机制的基础上,提出了多层联合恢复机制的思想,...IP over WDM网络是下一代网络的核心,生存性则是保证服务质量(QoS的关键要素。当网络中出现故障时,选择在IP层还是光层进行保护和恢复是非常重要的课题。文章在论述IP层和光层的保护和恢复机制的基础上,提出了多层联合恢复机制的思想,针对多层联合恢复机制中各层之间如何协调进行了仔细的分析,并提出了自己的见解。展开更多
基金Supported by State Science and Technology Commission of China
文摘A simple WDM Add-Drop Multiplexer (ADM) Consisting of a set of Er-doped fibers (EDF) and a shared pump is proposed. The chief benefit of the module is that the interchannel power spread does not accumulate from stage to stage in a cascaded WDM system. Moreover, the power differences caused by different component losses existing in the WDM networks can be automatically compressed. The cost will not increase a lot since the pump source is shared in the module. The performance of a cascaded system constructed from the modules has been carefully studied by computer simulation.
文摘IP over WDM is being envisioned as one of the most attractive architectures for the next generation Internet. This paper introduces two novel backbone node structures for IP over WDM networks. These node structures can be used as improvement approaches to DPDP (default path and dedicated path) method. The flow classifiers, which are the main components of these node structures, and the performance metrics of these structures, are also discussed.
文摘Integrating IP and WDM is an attractive direction for research. Many solutions have been presented but it is noted that the existing switching technologies still need more concern. Since optical packet switching is not practical yet, there are just two possible solutions left. One is wavelength routing(WR), which is circuit switching in essence and the other is newly proposed optical burst switching (OBS). In this paper, characteristics of WR and OBS are first described, then, compared in several aspects. It is notice that in many aspects, the wavelength routing and burst switching are complement. This stimulates us to propose a new switching architecture, which may be considered as 'mixture' of WR and OBS. We believe the network built on new switching structure can accommodate the requirements of practicability, flexibility, robustness, efficiency and etc. simultaneously. However, many related problems still need to be further researched.
文摘对IP over WDM的虚拓扑设计算法进行了研究,选择网络整体流量的均衡性作为优化目标,提出了一种新型的虚拓扑构造算法。在算法中,选择负载分布方差作为评价流量均衡性的指标,并给出其定义和计算方法。主要针对拥塞概率性能,在光层和IP层将提出的新型虚拓扑构造算法与其他算法进行比较。在光层的算法比较部分,选择负载均衡启发式路由算法(RLBH,routing with load balancing heuristics)与提出的算法进行比较;在IP层的算法比较部分,选择固定路径最小拥塞路由算法(FPLC,fixed-path least-congestion)与提出的算法进行比较,并对比较结果进行了讨论。比较结果显示在拥塞概率性能方面,提出的新型虚拓扑构造算法优于RLBH算法和FPLC算法。
文摘为了优化利用IP层和WDM层网络资源,在WDM网络集成辅助图模型的基础上,提出了一种面向IP/GMPLS over WDM网络的基于代价的优化综合路由算法,即CIR(Cost-based Integrated Routing)。该算法将IP层和WDM层资源可用信息以代价函数形式给出,并将因网络拓扑结构和网络负载分布不均衡等产生的瓶颈链路以及带宽碎片问题也统一纳入考虑,由此将LSP建立问题转化为在集成辅助图上找出一条源、目的节点之间的最短通路问题。仿真结果表明:CIR算法有效地实现了IP和WDM两层资源的联合优化,提高了网络资源利用,降低了网络阻塞率。
文摘IP over WDM网络是下一代网络的核心,生存性则是保证服务质量(QoS的关键要素。当网络中出现故障时,选择在IP层还是光层进行保护和恢复是非常重要的课题。文章在论述IP层和光层的保护和恢复机制的基础上,提出了多层联合恢复机制的思想,针对多层联合恢复机制中各层之间如何协调进行了仔细的分析,并提出了自己的见解。
