多光纤ASON网络动态路由优化算法

本文研究了多光纤波分复用光网络中的动态路由和波长分配问题,提出了基于分层图模型的一种新的多光纤网络的动态路由优化算法,该算法将连接请求的建立转化为在分层图模型中为该请求寻找一条最优路径,这使得设计者可以同时考虑路由和波长分配的问题,从而取得更好的效果。模拟结果显示基于分层图模型的(MFD-RWA:Multi-Fiber Dynamic Routing and Wavelength Assigrment)算法优于传统的动态最短路径算法。     

基于蚁群算法的分布式卫星光网络波长路由分配技术研究

为了解决分布式卫星光网络波长路由分配复杂的问题,论文提出基于小窗口策略的蚁群优化算法。采用链路可持续时间和波长空闲率作为启发函数,在实现负载均衡的同时,降低网络的拥塞率;引入小窗口策略引导蚂蚁在最小路由请求区域内进行选路,提高了算法的收敛速度;通过计算相邻链路空闲波长的交集,实现了由单只蚂蚁同时完成路由选择和波长分配。对单主星和双主星两种场景下的算法性能进行了仿真分析,结果表明:与经典的Dijkstra+FF算法相比较,单主星和双主星时的网络拥塞率最高分别降低了0.5和0.7,网络资源利用率改善最高可达到0.45和0.50。     

多光纤ASON网络动态路由优化算法

本文研究了多光纤波分复用光网络中的动态路由和波长分配问题，提出了基于分层图模型的一种新的多光纤网络的动态路由优化算法，该算法将连接请求的建立转化为在分层图模型中为该请求寻找一条最优路径，这使得设计者可以同时考虑路由和波长分配的问题，从而取得更好的效果。模拟结果显示基于分层图模型的(MFD—RWA：MultiFiber Dynamic：Routing and Wavelength Assignment)算法优于传统的动态最短路径算法。     

多域光网络中基于优先级的波长路由分配算法

本文提出一种在多域光网络中基于优先级的路由波长分配算法.算法设计旨在解决复杂网络拓扑下,多任务请求路由波长分配问题.本文首先根据复杂网络拓扑情况与任务请求状况,完成多域的划分,对跨域任务的最短路由进行路由分裂;其次依据域内与域间优先级设定策略,完成多任务请求优先级设定;按照优先级顺序,采用模糊优化波长分配算法完成波长分配.仿真结果表明本算法在处理复杂网络拓扑、多任务路由波长分配问题上效果明显,有效的降低了网络请求阻塞率,提高了光网络资源利用率.     

软件定义卫星光网络蚁群优化波长路由技术

针对卫星光网络中网络拓扑动态时变和业务类型多样化的问题,研究了在软件定义网络架构下保障服务质量的路由技术,提出了一种基于多业务的卫星光网络蚁群优化波长路由算法。通过改进蚁群算法的启发函数,将波长空闲率、时延、时延抖动、丢包率作为蚂蚁选路的重要依据,为业务选择了满足多种服务质量的最优路径;采用分组波长分配方法对不同等级的业务进行了区分服务,为不同业务分配了不同的波长集。仿真结果表明:与CL-ACRWA算法和Dijkstra算法相比,降低了卫星光网络的平均时延、平均时延抖动、平均丢包率,提高了波长利用率,同时也降低了高优先级业务的网络拥塞概率。     

一种基于自适应蚁群算法的动态RWA算法

动态RWA(路由与波长分配)问题是智能光网络的核心问题,以蚁群算法为代表的启发式算法是解决此类问题的优选方案之一。文章提出一种基于ADACO(自适应蚁群优化)算法的RWA机制,针对信息素挥发系数ρ采取自适应策略,实现了对全局信息素更新态调节。理论分析和数值仿真结果表明,与Dijkstra+FF(首次命中)算法相比,改进的ADACO+FF算法可以有效地降低网络阻塞率,规则型Mesh网络和NSFNET(国家科学基金会网络)的阻塞率最高分别降低了0.3和0.2。     

一种基于改进蚁群算法的光网络动态RWA机制

动态RWA(路由与波长分配)问题是智能光网络的核心问题.文章提出一种解决动态RWA问题的改进蚁群算法,在转移概率中加入了链路的空闲率作为约束条件,同时还引入了随机扰动防止搜索过早收敛于局部最优路径.仿真结果表明,改进算法与传统Dijkstra+ FF(首次命中)算法相比,可以显著降低阻塞率,提高资源利用率.     

WDM 网络中基于优先级的多任务波长路由分配算法

提出了一种在WDM网络中基于优先级的多任务波长路由分配算法。算法设计旨在提高光网络资源的利用率、降低网络请求阻塞率。分析了任务请求的路由类型以及负载容量对请求优先级划分的影响方式,给出了网络请求优先级划分策略,结合网络的实时状态提出了一种基于优先级的多任务波长路由分配算法。仿真结果表明,该算法相比现有算法降低了网络请求阻塞率,提高了资源利用率。     

基于蚁群系统的分布式RWA算法研究

针对波分复用(WDM)光网络中动态选路和波长分配(RWA)问题，提出了一种基于蚁群算法的分布式动态RWA方法。将蚁群算法与分层图模型结合，实现了RWA的并行计算。仿真结果表明，与现有最短路径法相比，该算法能有效地降低光路阻塞率，促进波长资源的合理分配，同时分布式的计算方式也降低了现代频繁变化的大型光网络的通信开销。     

智能光网络中的路由和波长分配问题

随着下一代智能光网络概念的提出，应用于传统光网络的路由和波长分配方法面临着许多新的挑战。本以自动交换光网络为代表，分析了智能光网络中不同类型连接的特点和实现路由和波长分配的控制软件模块，并着重从路由模式、多粒度分层选路、路由和波长分配算法、信令路由协议等几个方面出发，对智能光网络中的路由和波长分配问题进行了深入的探讨。同时提出了相应的解决方案。     

Ant colony optimization based load balancing routing and wavelength assignment for optical satellite networks

An ant colony optimization (ACO) based load balancing routing and wavelength assignment (RWA) algorithm (ALRWA) was put forward for the sake of achieving a fairy load balancing over the entire optical satellite networks. A multi-objective optimization model is established considering the characteristic of global traffic distribution. This not only employs the traffic intensity to modify the light path cost, but also monitors the wavelength utilization of optical inter-satellite links (ISLs). Then an ACO algorithm is utilized to solve this model, leading to finding an optimal light path for every connection request. The optimal light path has the minimum light path cost under satisfying the constraints of wavelength utilization, transmission delay and wavelength-continuity. Simulation results show that ALRWA performs well in blocking probability and realizes efficient load balancing. Meanwhile, the average transmission delay can meet the basic requirement of real-time business transmission.     

A distributed ant-based algorithm for routing and wavelength assignment in an optical burst switching flexible spectrum network with transmission impairments

This work describes a distributed algorithm inspired by ant colony optimisation for a solution to the problem of dynamic routing and wavelength assignment with wavelength continuity constraint in optical burst switched networks. The evaluation was conducted in a wavelength division multiplexed network environment with limited number of wavelength channels and in a flexible spectrum network environment undergoing transmission impairments. The simulations in the flexible spectrum network environment aim to replicate the effects of both linear and nonlinear physical layer impairments. Under these effects, an optical burst control packet could be lost during traversal of the network with no measure in place to notify the network of the loss or to free up optical resource reservations. The optical burst switching acknowledgement protocol has been modified in this work to account for a burst control packet failure by implementing a traversal acknowledgement to cater for its loss. The performance of the distributed ant-based algorithm has been extensively evaluated on several network topologies and compared with that obtained by shortest path routing and ant colony routing and wavelength assignment. The results show that the distributed ant-based algorithm significantly improves the burst transmission success probability in the wavelength division multiplexed network environment and provides a good solution in the flexible spectrum network environment undergoing transmission impairments.     

基于强化学习的光传送网路由波长优化

针对光传送网中动态业务的路由和波长问题,提出一种基于强化学习的深度路由波长分配算法DeepRWA。算法基于软件定义网络架构,通过强化学习灵活地调整控制光传送网,实现光网络路由波长分配策略优化。针对路由选择问题,结合链路上的波长使用情况,使用A3C算法选择合适的路由,使得阻塞率最小;针对波长分配问题,使用首次命中算法选择波长。考虑阻塞率、资源利用率、策略熵、价值损失、运行时间及收敛速度等多个指标,利用14节点NSFNET网络拓扑仿真实验。结果表明:当信道中包含18个波长时,与传统KSP-FF算法相比,所提出的路由波长分配算法的阻塞率降低了0.06,资源利用率提高了0.02,但运行时间有增加;在波长数超过45以后,与传统KSP-FF算法相比,所提算法保持阻塞率和资源利用率的同时,运行时间开始降低;当信道中包含波长数为58时,与传统KSP-FF算法相比,所提算法运行时间减少了0.07 ms。由此可见,提出的算法使路由选择和波长分配得到了优化。     

Design of the optical path layer in multiwavelength cross-connectednetworks

We discuss the wavelength requirement for optical networks based on wavelength-division multiplexing (WDM). A mathematical model, to represent the routing and wavelength assignment in optical networks with or without wavelength conversion, is described, and metrics are defined to express the performance. A new heuristic for routing and wavelength assignment is proposed and compared with the Dijkstra algorithm and with a solution based on integer linear programming. The different techniques are applied to a variety of network examples with different traffic loads     

Routing and Wavelength Assignment in Multi-Segment WDM Optical Networks using Clustering Techniques

This paper studies the routing and wavelength assignment (RWA) problem in multi-segment optical networks. The notion of network segment is referred to any part of the network that requires special consideration of wavelength routing such as separate administrative domains in a large scale optical network, sub-networks run by various service providers, etc. In multi-segment optical networks, each segment has different resource availability or hardware characteristics. The differences between multi-segment optical networks and homogeneous optical networks are discussed. We then present a resource abstraction technique called blocking island and define a multi-segment blocking island graph (BIG) network model. Using a minimum splitting routing heuristic introduced in the context of the blocking island paradigm in conjunction with the multi-segment BIG model, we propose a general RWA algorithm that takes a combined view of the network resource to integrate routing, wavelength assignment and gateway selection in a single routing framework. In the simulation, we demonstrate the effectiveness of our proposed algorithm by comparing it with other state-of-the-art heuristics in this area.     

基于多条件约束的ASON动态组播路由算法

在将自动交换光网络(ASON)建模成着色多重图的基础上采用综合成本策略,设计了一种新的最小综合成本路径计算算法,并结合组播成员的动态变化特性提出一种满足多条件约束的动态组播路由(DMRMC)算法,使组播路由和波长分配在同一过程内完成,且尽可能使组播树的综合总成本最小,同时局部优化波长转换次数、分光次数和不同波长的使用数量。仿真实验表明,本文算法有效可行,与采用单成本策略的组播算法相比,其取得了更低的综合成本和更好的连接阻塞性能。     

Virtual-node-based multicast routing and wavelength assignment in sparse-splitting optical networks

This paper investigates several problems associated with optical multicast routing and wavelength assignment in sparse-splitting optical networks for interactive real-time media distribution. Unfortunately, the constrained multicast routing with optimized wavelength assignment leads to NP-complete condition. Thus, in this paper, a virtual-node-based multicast routing algorithm is first proposed to satisfy the requirements of interactive real-time multicasting as well as the constraints from underlying optical networks. For the constructed multicast tree, we then associate an effective wavelength assignment algorithm. The experimental results show that the proposed algorithm combination performs well in terms of (1) the wavelength channel cost, (2) the maximum variation of inter-destination node delays, (3) the signal quality, and (4) the number of wavelength conversions.