多层网络中的联合资源配置方案

在多层网络的资源配置中,为了实现备份资源在各网络层的最大共享,在综合考虑网络各层的资源使用信息和拓扑信息的基础上,提出了一种联合的资源配置方案.在建立资源分配方案的整数线性规划模型的同时,提出了适合解决大规模网络的遗传算法.数值结果表明:联合资源配置方案可以更好地共享各网络层的备份资源,从而使多层网络具有更高的带宽利用率和更低的运营成本.由于引入了各网络层的协调,从而防止了回路问题.     

多波长复用光传送网的生存结构

本文讨论了光传送网的传送和监控机制,按照传送网通用功能结构的定义,分析了光传送网几种保护交换方式内在的机制,讨论了各自应该属于路径保护还是子网连接保护.在此基础上给出了光信道保护环和光复用段保护环详细的功能结构,同时简要地介绍了这两种保护环信息建模中需要用到的对象类.     

波分复用全光通信网中的放大自发辐射噪声积累效应研究

给出了一种全光通信网波长域计算机模拟方法，模拟了波分复用信号经过３个光分插复用节点后的信号及放大自发辐射积累的光谱图，并与实验结果进行了对比。计算了波分复用信号经过５０个光分插复用节点极限情况下的信噪比，结果表明放大自发辐射噪声积累造成的信噪比下降仍然可以保证接收机在１０Ｇｂ／ｓ时的误码率小于１０＾－９。这些结果可以被应用到未来国家或地区级全光通信网中。     

熔锥平面型三光纤耦合特性分析

以线性耦合波方程为基础，分析了具有不同耦合强度的平面型三光纤耦合系统的模场特性和功率耦合特性，并与常规的平面型三光纤耦合系统的耦合特性作了比较，给出的耦合器谱响应实验结果与理论结果较为一致。     

时隙光分组交换网络中一种新的光缓存优化配置方案

研究了时隙光分组交换网中的光缓存配置方案,针对反馈共享式缓存结构,通过对传统的连续分布式光缓存结构中不同延迟粒度的光缓存丢包的分布情况仿真结果研究,发现在传统的连续分布式光缓存结构中,丢包主要发生在小粒度的光缓存上,为此,提出通过适当增加小粒度的光缓存的方法,达到有效地降低丢包率,仿真结果显示,这种光缓存方案可以明显降低节点的丢包率.     

Protection switching schemes of multi-granularity p-cycles in survivable WDM networks

In this paper, a novel concept of multi-granularity p-cycle is proposed. In conventional p-cycle concept, all on-cycle spans have the same capacity. However, in multi-granularity p-cycle, each on-cycle span could have different capacity. Resnlts show that multi-granularity p-cycles are much more capacity-efficient and cost-effective than conventional p-cycles. We also propose two protection switching schemes for all types of p-cycle networks. One is wrapping protection, in which only two end nodes do real-time switching when a span failure happens. The other is steering protection, in which at most four nodes do real-time switching when a span fails. In steering protection switching scheme, the restoration path for the failure traffic demand has the least hops.     

WDM多纤环网的优化设计

本文讨论了WDM多纤环网(MFR)的优化设计问题,为解决该问题提出了新的整数线性规划公式.所采用的优化目标是最小化平均结点端口数目,以此为优化目标可以保证所设计的多纤环网具有最大的经济有效性.利用所提出的算法,我们定量分析了采用不同路由方案(波长通道和虚波长通道)的几种MFR结构(单向和双向)的网络性能.本文所获得的结论可作为选择合适MFR结构的参考.     

Dynamic protected lightpath provisioning in mesh WDM networks

This paper investigates the problem of dynamic protected lightpath services provisioning in optical mesh networks employing wavelength division multiplexing (WDM). A variety of schemes for dynamic protected services provisioning have been proposed, supporting a range of tradeoffs among restoration speed, capacity efficiency, and scalability. In this paper, we propose a novel scheme, called p-cycles-based maximum protected working capacity envelope (PC-MPWCE), which can offer an attractive combination of features: ring-like speed, mesh-like capacity efficiency, and good scalability. To evaluate the performance of PC-MPWCE, we compare it via simulation with 1 + 1 automatic protection switching (APS) and two well-known shared backup path protection (SBPP) on NSFNET. Our simulation results show that PC-MPWCE can achieve much better blocking performance than 1 + 1 APS, and perform the similar blocking performance and capacity efficiency as SBPP.     

Cross-phase modulation-induced penalties in multichannel DWDM optical transport networks

In dense wavelength division multiplexing (DWDM) optical transmission systems, cross-phase modulation (XPM) due to Kerr effect causes phase shift on each channel, which will ultimately be transformed to amplitude noise that leads to power penalties. In this letter, the XPM-induced penalty in multi-channel DWDM systems is investigated theoretically and an applied algorithm that can be practically used in engineering design is proposed.     

A new prediction method at the edge of optical burst switching network

To achieve lower assembly delay at optical burst switching edge node, this paper proposes an approach called current weight length prediction (CWLP) to improve existing estimate mechanism in burst assembly. CWLP method takes into account the arrived traffic in prediction time adequately. A parameter 'weight' is introduced to make a dynamic tradeoff between the current and past traffic under different offset time. Simulation results show that CWLP can achieve a significant improvement in terms of traffic estimation in various offset time and offered load.