基于相对容量损失的一种改进波长寻路算法

本文提出一种改进的基于相对容量损失（RCL）最小的波长分配和路由选择算法-DPRCL算法.该算法通过发送探测报文得到光路容量损失率,从而选择具有最小光路容量损失率的波长和路由建立连接.在不牺牲阻塞性能的情况下,DPRCL大大减小了实现复杂度以及网络开销,并适用于采用分布式控制的自适应路由的网络环境,而不限于RCL的固定路由方式.     

波分复用波长路由节点的阻塞特性分析

利用概率统计理论的方法，从节点层次上定量分析了节点规模、复用波长数目以及波长转换对波分复用(WDM)波长路由网络中波长路由节点的影响。提出了基于概率统计的节点阻塞模型。数值结果突出表明波长转换能力越强的全光节点，其性能越优。为了提高网络资源的使用效率并增强全光网络的灵活性，必须实现全光网络中的虚波长路由波长转换器。通过数值计算找到了阻塞性能和代价的折中，研究中发现配置较低波长转换能力波长转换器的波长路由节点将会具备更强的性价比优势，当前在构建光通信系统时使用弱波长转换能力的光节点更可行。     

一种波长转换范围受限全光网中的波长分配算法

本文研究了波长转换范围受限全光网中的动态路由和波长分配问题,提出了一种固定备选路由条件下新的路由和波长分配算法.算法引入了波长相关性的概念,用波长关联权值定量描述了各路由的前后链路上不同波长之间的相互依赖关系.在建立连接时首先使用那些依赖性强,对其他路由影响小的波长,从全局的角度出发选择最优的路由和波长分配方案.计算机仿真表明,本文算法能够适用于稀疏网络和网状网,在均匀业务强度或者大部分业务量来自于长跳路由的情况下,本文算法能够显著降低网络阻塞概率和使用的波长转换器数目,有效提高系统性能.     

一种波长转换受限WDM网络的动态路由和波长分配算法

本文基于分层图模型,提出了在节点波长转换范围受限和波长转换器数目受限情况下,解决WDM网络的动态路由和波长分配问题的一种算法.通过计算机仿真,研究了本算法的性能以及这两种波长转换受限情况对网络阻塞率的影响.     

WDM全光网自适应路由和波长分配算法

研究了无波长转换WDM全光网的路由和波长分配算法（RWA）。通过对已有算法的分析和比较,提出了一种自适应最小跳数路由算法（ADMH）。此算法以最小跳数路由为基础,同时考虑网络状态的变化,因而不仅能尽量少使用网络资源,也能使网络资源的分布保持均衡。计算机模拟仿真的结果表明,这种算法性能在各种网络参数条件下优于或等于已有算法。     

全光网络迂回路由的算法及性能分析

分别对波长通道（ＷＰ）和虚波长通道（ＶＷＰ）两种机制的全光网络迂回路由算法的阻塞性能进行了数值分析，并给出了一个任意拓扑全光网络的计算机数值模拟，对比了两种机制的网络阻塞性能。     

基于改进蚁群算法的卫星光网络波长分配方法

路由与波长分配是下一代光网络的需要解决的核心问题之一。本文采用智能蚁群算法,研究了卫星光网络的路由与波长分配问题,为通信请求寻找最优的数据传输光路径。基于请求区域受限策略(Restricted Request Area,RRA)和链路波长负载平衡策略,建立了考虑传输延迟和波长连续性约束的双主星分布式星群节点结构光网络系统模型。利用智能蚁群路由和波长分配(Smart Ant Colony Routing AndWavelength Assignment,SAC-RWA)算法求解系统模型,以找到具有稀疏波长转换的卫星光网络中最小成本波长路径。所提出的算法允许单个蚂蚁同时完成路由和波长分配,仿真结果表明,RRA能够明显改进卫星光网络的性能,以略微增加拥塞率的代价显著降低了计算复杂度。     

稀疏波长变换网络性能分析与研究

文章对动态业务模型下的稀疏波长变换网络性能进行了分析与研究，对波分复用（WDM）网络中引入波长变换器后的网络性能进行了系统的仿真，分析了波长变换器数量、波长变换器位置、波长变换范围以及路由波长算法等因素对网络性能的影响。     

波长路由网络选路时的光信号质量限制研究

光网络中,路由与波长分配(RWA)算法是最优化网络性能的核心问题之一,传统的RWA算法都假设光网络的物理层状态是理想的,即不存在光信号传输损伤的问题.通过对这个缺陷的分析,将光信号的传输损伤问题充分考虑到路由与波长分配算法中,从算法的角度来实现对光信号的传输保护,这样做不仅能有效防止业务的物理损伤阻塞,还能极大地提高光网络的性能.     

基于节点功能的WDM光网络分布式路由与波长分配算法

建立了一种具有节点功能区分的WDM多波长光网络模型,根据节点功能将其分为A、B两类,在此基础上提出了波长等价弧和等价网络等概念,并根据此类多波长光网络模型的节点和网络结构特点以及相应的选路和波长分配策略,提出了一种基于节点功能的多波长光网络分布式路由与波长分配算法——BONF算法,证明了算法的可行性,分析了算法的计算复杂度,比较了此算法与其它同类型算法的区别,指出了BONF算法的优点和不足。     

An Ant-Based Approach for Dynamic RWA in Optical WDM Networks

In this paper, we propose a new ant-based algorithm for the dynamic routing and wavelength assignment (RWA) problem in optical WDM networks under the wavelength continuity constraint. Unlike conventional approaches, which usually require centralized global network information, our new RWA algorithm constructs the routing solution in a distributed manner by means of cooperative ants. To facilitate the ants’ foraging task, we adopt in our algorithm a probabilistic routing table structure for route selection. The new algorithm is highly adaptive in that it always keeps a suitable number of ants in the network to cooperatively explore the network states and continuously update the routing tables, so that the route for a connection request can be determined promptly by the current states of routing tables with only a small setup delay. Some new schemes for path scoring and path searching are also proposed to enhance the performance of our ant-based algorithm. Extensive simulation results upon three typical network topologies indicate that the proposed algorithm has a very good adaptability to traffic variations and it outperforms both the fixed routing algorithm and the promising fixed–alternate routing algorithm in terms of blocking probability. The ability to guarantee both a low blocking probability and a small setup delay makes the new ant-based routing algorithm very attractive for both the optical circuit switching networks and future optical burst switching networks     

Routing Mechanisms Employing Adaptive Weight Functions for Shortest Path Routing in Optical WDM Networks

Optical dense wavelength division multiplexed (DWDM) networks are an attractive candidate for the next generation Internet and beyond. In this paper, we consider routing and wavelength assignment in a wide area wavelength routed backbone network that employs circuit-switching. When a session request is received by the network, the routing and wavelength assignment (RWA) task is to establish a lightpath between the source and destination. That is, determine a suitable path and assign a set of wavelengths for the links on this path. We consider a link state protocol approach and use Dijkstras shortest path algorithm, suitably modified for DWDM networks, for computing the shortest paths. In [1] we proposed WDM aware weight functions that included factors such as available wavelengths per link, total wavelengths per link. In this paper, we present new weight functions that exploit the strong correlation between blocking probability and number of hops involved in connection setup to increase the performance of the network. We also consider alternate path routing that computes the alternate paths based on WDM aware weight functions. The impact of the weight functions on the blocking probability and delay is studied through discrete event simulation. The system parameters varied include number of network nodes, wavelengths, degree of wavelength conversion, and load. The results show that the weight function that incorporates both hop count and available wavelength provides the best performance in terms of blocking probability.     

Fuzzy Least-Congested Path Routing and Improved Remote-Path Routing based on Hierarchical Information in WDM Networks

Although routing schemes based on global knowledge make most optimal routing decisions, they will occupy many resources to keep the state information of the network up-to-date. In this work, we describe a fuzzy least-congested path (FLCP) routing algorithm based on hierarchical information. Simulation shows that the blocking probability using FLCP is very near to the blocking probability using the least-congested path routing (LCP) algorithm based on global information. Under heavy traffic load, the FLCP algorithm is superior to the exhaustive algorithm (EA) and the LCP algorithm with unit information cost. The FLCP algorithm provides better routing, even with incomplete information. Thus, the algorithm requires less information of the network, particularly under heavy traffic load. In addition, an improved remote-path routing approach is provided to reduce the blocking probability of connection requests to a node that is many hops away from the source node.     

一种新型的动态路由和波长分配算法

本文讨论了WDM光网中，在动态业务流量和有限范围波长变换情况下的动态路由和波长分配（RWA）问题，基于Moone-Dijkstra算法，考虑到动态波长变换的可能和限制，提出了一种新型的、可实现动态最小代价路由和最佳虚波长通道的综合启发式算法（DMC－OVMP）。该算法对路由子问题和波长分配子问题既相互独立，又相互结合，优化了RWA，保证了网络信息传输的安全性。对中国教育和科研计算机网（CERNET）基于本算法进行了计算机仿真，实现了低的网络阻塞率。     

DWDM波长路由网络光链路负载均衡的波长路由算法

提出了一种应用于密集波分复用(DWDM)波长路由网络(WRON)中光链路负荷均衡的思想,并将其应用于优化Dijkstra算法的权值,同时将优化Dijkstra算法用于遗传算法求得了在不同的负荷条件下波长下限的网络所需波长数目。并将优化前后的算法分别对美国自然科学基金(NSF)网络的最优波长分配进行数值分析,发现基于负荷均衡思想的优化Dijkstra算法能够对网络的性能有很大提高：当遗传代数为20代时,采用优化Dijkstra算法阻塞率降低了约36％;当波长使用数为7个时,降低网络阻塞率10％。     

备用路由下一种新的WDM动态路由波长分配算法

基于波长转换度的空闲波长图模型,提出了一种用于WDM光网络在备选路由下的动态RWA算法。路由选择采用K条最短路径算法进行,备选路由集中首选最佳路由时考虑链路的代价、跳数和每一个链路上不可用波长数。通过计算机模拟,分析这3个参数对网络的阻塞率的影响,结果表明本算法中所选定研究的3个参数中选定路由的不可用波长数对网络阻塞率的影响程度比通道的代价,跳数对网络的影响程度大,这个结论对算法中这3个参数数值的选取提供了依据,使算法能够依据实际网络情况动态选取参数,降低网络阻塞率。     

Dynamic Routing and Wavelength Assignment in Optical Networks by Means of Genetic Algorithms

We propose a novel genetic algorithm for solving the dynamic routing and wavelength assignment (DRWA) problem in wavelength-routed optical networks. The algorithm not only obtains low call blocking probability, but it also employs a very short computation time. Moreover, it is capable of providing fairness among connections, that is, to offer approximately the same quality of service (in terms of blocking probability) for all source-destination node pairs. Since requirements on optical network availability are highly severe, we also propose an extension of the algorithm to provide fault-tolerance capability at the optical layer. It is achieved by means of protection, where each optical connection request is provided with a pair of lightpaths (a primary and a backup lightpath). Again, the genetic algorithm proves to be highly efficient, in this case, at performing routing and wavelength assignment of pairs of lightpaths.     

一种快速动态分布式光链路建立方法

提出一种改进的波长分配算法,用于波长路由光网络中快速动态分布式光链路的建立。该算法采用提前释放和超时释放两种波长和链路释放机制,减少了网络拥塞,更适合波长路由网络的实际运行规则。通过在美国自然科学基金网(NSF)上的仿真计算,与以前的研究结果相比,该算法可以减少网络的阻塞率8％,同时缩短了光链路建立的时间。     

Dynamic Routing and Wavelength Assignment in Survivable WDM Networks

Dense wavelength division multiplexing (DWDM) networks are very attractive candidates for next generation optical Internet and intelligent long-haul core networks. In this paper we consider DWDM networks with wavelength routing switches enabling the dynamic establishment of lightpaths between each pair of nodes. The dynamic routing and wavelength assignment (RWA) problem is studied in multifiber networks, assuming both protection strategies: dedicated and shared. We solve the two subproblems of RWA simultaneously, in a combined way using joint methods for the wavelength selection (WS) and wavelength routing (WR) tasks. For the WS problem in contrast to existing strategies we propose a new, network state based selection method, which tries to route the demand on each wavelength, and selects the best one according to different network metrics (such as available channels, wavelengths per fiber and network load). For the WR problem we propose several weight functions for using in routing algorithms (Dijkstra or Suurballe), adapting dynamically to the load of the links and to the length of the path. The combination of different wavelength selection and routing (WS&WR) methods enables wide configuration opportunities of our proposed algorithm allowing good adaptation to any network state. We also propose the extension of the RWA algorithm for dedicated and shared protection and a new method for applying shared protection in dynamic WDM environment. The detailed analysis of the strategies demonstrate that our RWA algorithm provides significantly better performance than previous methods in terms of blocking probability whether with or without protection methods.