IP over WDM光网络中的业务疏导机制研究

针对当前IP overWDM光网络中业务量疏导技术研究的问题,提出了一种新的支持多优先级服务质量的业务疏导机制。该机制结合了抢占和流量分割技术,能够基于业务流QOS的需求选择恰当的疏导路径。仿真结果表明,该机制能有效降低具有时延约束的高优先级连接请求阻塞率。     

WDM光网络动态业务流量的可重构疏导

流量疏导是当今光网络研究中一个学术与商业价值并重的研究热点。在WDM(波分复用)光网络中使用流量疏导技术不仅能够有效地降低网络成本，也能够使网络性能得到必要的优化。为了适应当前网络中普遍存在的突发多变的业务分布，引入了一种称为网络可重构动态流量疏导的新型流量疏导概念，并对疏导进行了分类，较全面地论述和评价了近年来这方面的研究，最后对今后的研究作了一番展望。     

WDM光网络中动态流量的疏导

流量疏导是当今光网络研究中的一个前沿和热点问题,在波分复用(WDM)光网络中使用流量疏导技术能有效降低网络的成本,减少网络节点中业务信息的处理量.文章讨论了动态流量疏导的意义及其分类,分析了关于在各种网络结构中动态流量疏导的研究近况,最后对今后的发展方向做了一番展望.     

WDM光网络中的业务量疏导

波分复用（WDM）技术在主干传送网中巳广泛应用，WDM光网络的研究进展也非常迅速，光网络中的业务量疏导定义为复用、解复用和交换低速率业务流到大容量的光路中的行为。介绍了WDM光网络的业务量疏导的重要性，研究方法及其最新研究进展情况。     

业务疏导技术在WDM网络及OPS网络中的应用

在波分复用(WDM)光网络中,可使用业务疏导(Traffic Grooming)技术来提高网络性能,降低网络成本.详细阐述了WDM光网络中业务疏导的基本概念及主要目标,并对国内外研究现状进行了总结.最后介绍了OPS光交换网络中使用的业务疏导技术.     

WDM光网络多跳业务量疏导算法

针对具有多跳疏导能力的WDM光网络进行了研究,提出了一种基于固定备选路由的多跳业务量疏导算法（FO-HC-MH）。该算法对备选路由的跳数进行限制,因而可以节约使用网络的收发器资源。仿真实验表明,与FO-MH算法相比,在网络负载较低的情况下该算法节约效果明显。     

多播格状WDM光网络中流量疏导的一种启发性算法

波分复用技术的开发应用及网络业务信息的多样化促进了多播技术的应用和发展.由于网络中波长带宽与节点间业务信息需求之间的巨大反差,使流量疏导成为必要,以节约网络资源和成本.但多播的出现使流量疏导算法变得更复杂多样.本文提出了对多播格状网络中的静态流量进行有效疏导的一种启发性算法,并取得较为优化的结果.     

WDM网络的动态业务疏导算法

光网络普通用户大量的一般业务请求数目及波长通道带宽的不断增加,极大地增加了网络中电层和光层设备的处理负担,加大了网络成本.对低速电信号复用到高速光通道进行优化,减少网络电层设备的使用,降低网络成本的业务疏导技术成为目前光网络研究的一个热点.文章研究了网络节点具有光收发器数目限制及不具有波长变换能力时的动态业务下的选路与波长分配问题,提出了基于分层图模型的自适应算法并通过仿真实验证实了其有效性.     

WDM疏导网络中的基于连接的动态恢复

针对WDM网络中单链路出错的生存性流量疏导问题,提出了一种基于连接的动态恢复机制(DRAC).DRAC不预留任何资源,当链路出错时,通过在网络中动态的发现资源来对错误进行恢复,将一个出错连接转发到一条新的多跳路径.仿真结果显示,提出的这种动态恢复机制拥有很高的恢复概率.     

支持多优先级QoS的业务量疏导算法

针对当前业务量疏导研究中很少涉及的QoS约束的问题,提出并研究了一种支持多优先级QoS的业务量疏导算法（Differentiated Traffic Grooming Algorithm,DTGA）,该算法综合考虑了对不同等级业务QoS和网络资源利用率的优化。与目前实用的WDM光网络业务量疏导算法的性能仿真对比表明,DTGA能有效地降低高服务等级需求业务的阻塞率和节省网络资源。     

Grooming of Arbitrary Traffic in Optical WDM Mesh Networks Using a Genetic Algorithm

In this paper, a genetic algorithm is proposed for grooming of arbitrary traffic in optical mesh networks. Traffic streams are routed in the wavelength division multiplexing (WDM) grooming networks that comprise both fiber links and established lightpaths. Chromosomes are split into multiple versions when multiple shortest routes are found. The selection strategy is based on a comparison between chromosomes. A variety of cost functions are proposed for the routing algorithm and two comparison methods are considered in the selection procedure. Computer simulations are performed with randomly generated traffic patterns. The results show that the algorithm is effective for traffic grooming (TG) problems, and also for routing and wavelength assignment problems.     

Minimal Delay Traffic Grooming in WDM Optical Star Networks

All-optical networks face the challenge of reducing slower opto-electronic conversions by managing assignment of traffic streams to wavelengths in an intelligent manner, while maximizing the bandwidth resources utilization. This challenge becomes harder in networks closer to the end users that have insufficient data to saturate single wavelengths as well as traffic streams outnumbering the usable wavelengths. Traffic grooming has been proposed as a possible solution in the network closer to the end users. However, it requires costly traffic analysis at access nodes. We study the problem of traffic grooming that reduces the need to analyze traffic, for a class of network architecture mostly used by Metropolitan Area Networks; the star network. We first prove that the problem is NP-hard, then provide an efficient greedy heuristics that can be used to intelligently groom traffics at the LANs to reduce latency at the access nodes. Simulation results show that our greedy heuristics achieves a near-optimal solution.     

Heuristic Algorithms for Grooming of Arbitrary Traffic in WDM Ring Networks

In a wavelength division multiplexing (WDM) network, sub-wavelength traffic streams can be elaborately arranged in wavelength channels to minimize the number of required electronic end systems, known as the traffic grooming problem. In this paper, a modified genetic algorithm without crossover operation is proposed to solve the problem using a permutation-based chromosome representation and using a selection strategy of reproducing the best chromosomes, thereby minimizing the number of electronic devices and requiring less wavelengths. Then, three methods are developed to improve the performance of the algorithm and a hill-climbing algorithm is proposed for the same purpose. Computer simulations were performed with plenty of randomly generated traffic patterns in unidirectional rings. The results show that these methods can improve the algorithm considerably. The relationships between the minimized network cost and the number of nodes are also presented.     

Effective Traffic Grooming Algorithms in SONET/WDM Ring Networks

Much work has focused on traffic grooming in SONET/WDM ring networks. Previous work has considered many aspects of traffic grooming, including minimizing the number of ADMs, minimizing the number of wavelengths, considering different traffic models, using different network architectures, incorporating switching capability and so on. In this work, we study traffic grooming in unidirectional ring networks with no switching capability under both uniform traffic and non-uniform traffic models to reduce electronic multiplexing costs. Based on the clustering notion, we derive a general and tighter lower bound for the number of ADMs required in traffic grooming under the uniform all-to-all traffic model. This bound reduces to special cases obtained in previous work. We also derive general, tighter, and closed form lower bounds for the number of ADMs required under two non-uniform traffic models: the distance-dependent traffic model and the non-uniform symmetric traffic model. Cost-effective multi-phase algorithms that exploit traffic characteristics are then designed and studied to efficiently groom traffic streams under different traffic models. Our numerical and simulation results show that the proposed multi-phase algorithms outperform existing traffic grooming algorithms by using a fewer number of ADMs. Our algorithms in several cases also achieve the lower bounds derived.     

WDM光网络中的业务疏导

目前WDM光网络普通用户大量的一般业务请求数目及波长通道带宽的不断增加极大的增加了网络中电层和光层设备的处理负担,增加了网络成本。对低速电信号复用到高速光通道进行优化,减少网络电层设备的使用,降低网络成本的业务疏导(TrafficGrooming)技术成为目前光网络研究的一个热点。本文主要介绍了WDM光网络中的业务疏导问题的基本概念、技术特点、国内外研究现状进行了总结。     

Dynamic Grooming Algorithms for Survivable WDM Mesh Networks

Within a WDM grooming mesh network and under the constraints of the number of transceivers per node and wavelength continuity, we propose a novel dynamic grooming graph which models the number of transceivers per node in addition to the usage of wavelength and bandwidth resources. Based on the grooming graph, we first propose a dynamic traffic-grooming algorithm called integrated grooming algorithm (IGA). And we also propose two dynamic survivable traffic-grooming algorithms, which are called protection per lightpath traffic-grooming algorithm (PPL) and protection per connection traffic-grooming algorithm (PPC). These algorithms are evaluated via simulations.