WDM疏导网络中一种新的多播业务路由算法

研究了波分复用(WDM)网状网中动态多播业务量疏导,提出一种新的辅助疏导模型,其可以描述当前网络资源状况和节点分光特点,并动态更新.进而提出一种有效的多播业务量疏导启发式算法(MGA),将业务的多播选路和波长分配同时完成.仿真表明,该算法在波长连续性限制、网络波长和节点收发器数目有限的情况下,具有较低网络阻塞率.     

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业务量疏导网络中的动态共享通路保护算法

本文研究了WDM业务量疏导网状网中的生存性问题,基于分层图模型提出了一种动态的业务量疏导共享通路保护算法(SPPTG).该算法根据网络拓扑信息、资源使用情况和到达的业务连接请求动态调整波长通道的代价,在此基础上为到达的低速业务连接请求寻找两条链路分离的通路,分别作为工作通路和保护通路,并且保证保护通路尽量共享已有的保护资源,从而有效提高全网的资源利用率.仿真表明SPPTG算法具有很好的阻塞性能,同时可以充分共享保护资源.     

WDM中基于业务带宽的业务量疏导算法

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.文章提出了一种基于带宽优先级的启发式算法,将业务的选路与波长分配同时完成.仿真表明,该算法在波长连续性限制,网络波长数目有限的情况下具有较低的阻塞率.     

一种WDM网状网中基于共享保护的业务量疏导算法

在WDM网络中业务的带宽需求远低于一个波长所提供的带宽,业务量疏导可以聚集低速业务到大容量的光路中从而有效地利用波长带宽资源.目前大多数业务量疏导的研究限于环形网,考虑对WDM网状网中低速业务可靠疏导的文献更少.该文综合考虑WDM网状网生存性及业务量疏导,提出了基于波长分层图的共享保护业务量疏导算法(SPTG-LG,Shared Protection Traffic Grooming algorithm ba,sed on wavelength Layered-Graph),并对算法进行了仿真和分析.     

波分系统链、环状网络动态业务疏导的波长选择算法及仿真

针对基于业务疏导的WDM网络模型的两种不同的网络优化目标,提出并仿真了在已用波长优先情况下6种波长选择算法方案,计算机仿真结果表明,基于概率模型的业务疏导波长选择算法和基于业务起止位置的带宽负载度算法具有较好的性能。最后指出了这些算法的应用领域。     

WDM网状网中支持业务量疏导的区分共享保护算法

该文综合考虑WDM网状网生存性及业务量疏导,采用部分光路共享保护机制为低速业务提供满足其可靠性和带宽需求的连接,提出了一种基于波长分层图的支持业务量疏导的区分共享保护算法—部分共享保护业务量疏导算法PSPTG(PartialShared-pathProtectionalgorithmsupportingTrafficGrooming)。仿真结果表明:该算法可以较好地利用资源。     

一种新的基于集成图模型的综合疏导算法

在IP over WDM网络的业务疏导中,针对现有图模型的缺陷、设计了一种可用于各种疏导策略计算的集成图模型.它克服了分层图不能量化资源占用的缺点,以及LBAG图不能满足光路的波长连续要求的缺点.基于集成图模型,提出了一种考虑光收发器资源、波长资源以及路径上O/E/O次数等信息的综合疏导算法(Integrated Grooming Algorithm,IGA).仿真结果表明,相比VT-first和PT-first等只侧重于减少某种资源占用的疏导算法,IGA能提高网络吞吐量,减少O/E/O处理次数.     

WDM光网络的多优先级业务疏导机制

IP over WDM网络中,业务疏导能有效提高波长带宽利用率.然而,单一化的业务疏导机制难以满足不同业务的QoS要求,也很难做到经济合理地使用光路.提出了一种支持多优先级业务的疏导机制,该机制根据光路传输的时延和丢包特性来选择恰当的疏导路径,同时,该机制结合了抢占和流量分割技术,能有效地实现流量分割和多路抢占,降低了业务的阻塞概率.仿真结果显示,该疏导机制在保证业务QoS的同时,降低了高优先级业务的阻塞概率;在业务负载低时,能有效减少抢占.     

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 Routing in WDM Grooming Networks

Traffic grooming in optical networks has gained significant importance in recent years due to the prevailing sub-wavelength traffic requirement of end-users. In this paper, a methodology for dynamic routing of fractional-wavelength traffic in WDM grooming networks is developed. To evaluate the performance of routing algorithms, a new performance metric that reflects the network utilization is also proposed. The performances of shortest-widest path, widest-shortest path, and available shortest path routing algorithms are evaluated on a class of WDM grooming networks by considering traffic of different capacity requirements. The effect of dispersity routing, where higher capacity requests are broken into multiple unit capacity requests, is also investigated. The most interesting counter-intuitive result that is observed is that increasing the grooming capability in a network could result in degrading the performance of the widest-shortest path algorithm.     

A Link Bundled Auxiliary Graph Model for Constrained Dynamic Traffic Grooming in WDM Mesh Networks

This paper addresses the two-layer dynamic traffic grooming problem in wavelength-division-multiplexed (WDM) mesh optical networks subject to resource constraints and the generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint which incorporates various kinds of wavelength conversion capabilities that exist in optical networks. As an improvement over the existing layered auxiliary graph (layered-AG) approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) model and propose the SAG-LB method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose the constrained integrated grooming algorithm (CIGA) based on the LBAG model. A grooming policy influences the resource utilization by determining the weight function of the auxiliary graph. We propose the least resource path first (LR) grooming policy, which is an improvement over the existing grooming policies in the literature, by integrating the wavelength and transceiver metrics together. Simulation results show that the LBAG model achieves a comparable blocking performance with the layered-AG approach while using a significantly less amount of running time. We also present the worst case time complexity analysis of the CIGA grooming algorithm and evaluate the performance of the LR grooming policy by simulation.     

IPoverWDM光网络中基于滑动调度业务模型的节能业务量疏导算法研究(英文)

In this paper,we investigate on the problem of energy-efficient traffic grooming under sliding scheduled traffic model for IP over WDM optical networks,so as to minimize the total energy consumption of the core network.We present a two-layer auxiliary graph model and propose a new energyefficient traffic grooming heuristic named Two-Dimension Green Traffic Grooming(TDGTG) algorithm,which takes both space and time factors into consideration for network energy efficiency.We compare our proposed TDGTG algorithm with the previous traffic grooming algorithms for scheduled traffic model in terms of total energy consumption and blocking probability.The simulation results in three typical carrier topologies show the efficiency of our proposed TDGTD algorithm.     

光组播路由代价与波长使用量的联合优化方法

为解决光组播路由中组播中路由代价和波长资源消耗单一化造成的组播路树路由的代价过高问题,在分光节点约束条件下,提出了光组播路由代价与波长使用量联合优化的长路优先(LPF)方法和短路优先(SPF)方法。算法通过检查最小光组播树是否存在节点分光约束的问题,根据设置的波长使用代价控制因子,使LPF或SPF的路由代价和波长使用量最小。LPF方法首先选择组播树最长路径或新波长通道重路由受分光约束的目的节点,SPF方法先选择组播树中最短路径或新波长通道重路由受分光约束的目的节点,仿真结果表明,本文提出的两种联合优化方法都能实现路由代价较低和波长需求较少的目的。     

WDM网络中静态流量的最少费用疏导策略

为了解决WDM网状网络中的静态流量疏导问题,基于收发器节约辅助图模型,该文提出了一种最少费用疏导策略。它同时考虑收发器和波长链路两种网络资源的费用,为每条流量计算出一条费用最少的路径,以获得网络总费用最少的解决方案。根据两种资源费用的比值关系,给辅助图中的每条边分配不同的权值,使得路径的总权值最小代表了该路径的费用最少,从而就能够轻易地实现该策略。仿真结果证明,不管两种资源的费用比值如何变化,该策略的网络总费用始终是最少的。     

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.     

弹性光网络中面向任播业务的节能路由算法

为提高数据中心间光互联网络的能效,面向任播业务提出一种具有业务持续时间感知的混合路径传输节能路由算法.为了减少新建光路和工作元器件数量,优先采用单路径传输;若业务阻塞则以传输能耗最小化为目标进行多路径传输.除此之外,引入基于频谱预留的业务疏导策略来降低保护带宽和光收发器的开销.仿真结果表明:与传统节能路由算法相比,所提算法在显著降低网络能耗的同时,有效避免了业务阻塞率的过度增加,实现了网络能耗与性能的平衡.     

Minimum delay algorithm based on time aggregated graph in DTN network

The DTN network has the characteristics of dynamic topology change,thus the routing algorithm of static network can not solve the routing problem of time-varying network,and can not support fast transmission of given tasks.The existing time-variant routing algorithm CGR (contact graph routing) uses the earliest contact to obtain the shortest path,but because of the influence of the order of the connectivity period,the CGR algorithm has low link utilization.To solve this problem,the method of finding the shortest path was proposed.Besides,in order to characterize the relation between the different connect periods of the same link,the time series of node cache was added to the time aggregated graph.Based on this,the end-to-end multi-path shortest delay routing algorithm for the known task requirements was proposed.Finally,the feasibility of the algorithm was proved by an example.     

A novel generic graph model for traffic grooming in heterogeneous WDM mesh networks

As the operation of our fiber-optic backbone networks migrates from interconnected SONET rings to arbitrary mesh topology, traffic grooming on wavelength-division multiplexing (WDM) mesh networks becomes an extremely important research problem. To address this problem, we propose a new generic graph model for traffic grooming in heterogeneous WDM mesh networks. The novelty of our model is that, by only manipulating the edges of the auxiliary graph created by our model and the weights of these edges, our model can achieve various objectives using different grooming policies, while taking into account various constraints such as transceivers, wavelengths, wavelength-conversion capabilities, and grooming capabilities. Based on the auxiliary graph, we develop an integrated traffic-grooming algorithm (IGABAG) and an integrated grooming procedure (INGPROC) which jointly solve several traffic-grooming subproblems by simply applying the shortest-path computation method. Different grooming policies can be represented by different weight-assignment functions, and the performance of these grooming policies are compared under both nonblocking scenario and blocking scenario. The IGABAG can be applied to both static and dynamic traffic grooming. In static grooming, the traffic-selection scheme is key to achieving good network performance. We propose several traffic-selection schemes based on this model and we evaluate their performance for different network topologies.