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WDM网络中支持QoS的路由与波长分配算法 总被引:1,自引:1,他引:1
针对波分复用(wDM)网络中的路由与波长分配问题。提出了一种支持服务质量(QoS)的约束搜索算法。基于多目标规划模型,这种搜索算法可为网络各节点创建路由表,根据路由表信息求出非支配路径集合,从而一次性完成寻找路由和分配波长两项任务。仿真实例证明了该算法的有效性。 相似文献
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针对光突发交换(OBS)网络中已有的包括抢占和波长分离等服务质量(QoS)保证机制的不足,提出了一种改进的基于QoS的标签交换路径共享(QLS)算法。算法通过链路波长资源的统计复用,在保证高优先级业务传送的可靠性和有效性的同时,提升低优先级业务的QoS性能。使用开源离散事件仿真软件OMNeT++搭建了OBS/GMPLS仿真平台,对4×4对称型MESH网络和NSFNET网络分别采用WP算法和QLS算法进行了仿真。结果表明,QLS算法对于高QoS等级业务性能影响极小,MESH和NSFNET网络中class3业务的丢包率分别减少了近0.2和0.3,平均丢包率分别减少了约0.05和0.1。 相似文献
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This paper proposes a dynamic burst discarding scheme for deflection routing in optical burst switching networks. In general, deflection routing is effective in lightly loaded situations, whereas it has a contrary effect in congested networks because deflected bursts accelerate network congestion. Thus deflection routing should be employed in lightly loaded networks. Incoming traffic, however, varies in time and location, so that temporal and/or local congestion cannot be avoided. Our proposed scheme resolves this problem in the following way. Each node autonomously detects congestion with local information, and bursts to be deflected are discarded in a probabilistic manner, based on the degree of detected congestion and the numbers of elapsed and remaining hops of those bursts. Simulation experiments show that when congestion happens temporarily, the proposed scheme reduces the burst loss probability, and it utilizes network resources efficiently when local congestion happens. 相似文献
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在光网络中,光信号沿着路由与波长分配(RWA)算法选定的光通路传输的过程中会受到各种信号损伤的影响而导致信号质量的不断下降,严重影响着业务的服务质量(QoS).而光网络中多样化的客户层业务往往有着不同的QoS的需求,因此有必要根据不同的业务QoS需求对光信号损伤的影响进行不同程度的控制.针对这一问题,提出了一种能同时考虑信号损伤限制和服务质量区分的动态RWA算法,并通过计算机仿真的方法对其性能进行了分析和验证.结果表明:该算法既能克服光网络中信号损伤的影响又能为不同级别的业务提供不同的QoS保证,更贴近实际需求. 相似文献
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全光网静态路由选择和波长分配的分层图算法 总被引:1,自引:0,他引:1
文章提出一种将路由选择和波长分配结合起来的启发式的路由选择和波长分配(RWA)算法.通过这种新的分层图算法和限制光跳距的加权系数来优化全光网的静态路由选择和波长分配,使建立光连接时所需的波长数达到最少.最后对实际的ARPANet等5种光网络进行了计算机仿真,证明了本算法比以前的算法有更好的性能. 相似文献
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Reinaldo Vallejos Alejandra Zapata-Beghelli Víctor Albornoz Marco Tarifeño 《Photonic Network Communications》2009,17(3):266-276
Existing methods for handling routing and dimensioning in dynamic WDM networks solve the two problems separately. The main drawback of this approach is that a global minimum cost solution cannot be guaranteed. Given that wavelengths are costly resources, determining the minimum network cost is of fundamental importance. We propose an approach which jointly solves the routing and dimensioning problems in optical burst switching (OBS) networks, guaranteeing a target blocking per connection. The method finds the set of routes and the number of wavelengths per network link that minimise the total network cost. To accomplish this, an integer linear programming problem is solved. The proposed method was applied to ring networks, where the optimal solution achieves a reduction in the network cost of 10–40% (for traffic loads <0.4, compared to solving both problems separately). In the case of mesh topologies, to reduce the computational complexity of the method, we applied a variation of it which achieves a local minimum. Even so, a reduction of 5–20% (for traffic loads <0.4) in the network cost was obtained. This ability to lower network cost could make the proposed method the best choice to date for dynamic network operators. 相似文献
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文章分析了偏射路由对网络性能的影响,在分析发送端控制偏射路由技术的基础上,提出了基于阈值检测和数据更新的改进方案.边缘节点快速更新状态信息,并通过特殊控制分组传递链路拥塞的分布特征等信息;交换节点进行阈值检测,动态决定竞争时突发的传送方式,减少偏射路由对网络负荷的影响,进一步降低网络阻塞率,改善网络性能。 相似文献
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Amin Ebrahimzadeh Akbar Ghaffarpour Rahbar Behrooz Alizadeh 《Optical Switching and Networking》2013,10(4):354-365
Routing and wavelength assignment (RWA) is the most concern in wavelength routed optical networks. This paper proposes a novel binary quadratic programming (BQP) formulation for the static RWA problem in order to balance traffic load among a network links more fairly. Subsequently, a greedy heuristic algorithm namely variable-weight routing and wavelength assignment (VW-RWA) is proposed to solve the developed BQP problem. In this method, the weight of a link is proportional to the link congestion. Performance evaluation results for different practical network topologies show that our proposed algorithm can decrease the number of required wavelengths in the network, blocking rate and variance of used wavelengths in each link. Besides, it is shown that the number of required wavelengths to establish call requests for a given network topology can be reduced at lower cost compared to other heuristics. 相似文献
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Hoang‐Linh To Suk‐Hwan Lee Won‐Joo Hwang 《International Journal of Communication Systems》2015,28(11):1729-1740
We consider optical delay line buffer as a solution to reduce the number of lost burst in optical burst switching, one of the promising candidates for future networks. Such network takes burst loss as an important performance criteria in the design step. Network performance, however, cannot be captured efficiently using traditional queueing models, because they often ignore the impatience of messages traveling through optical switches which is one of the popular issues in communication networks. In this paper, we develop an analytic model for this system using queueing theory and considering special impatience features. Simulation results show that (i) the developed model with impatience features can decrease burst loss probability ( ? 10%) compared with other approaches, and (ii) applying that model, we demonstrate that shared buffer architecture in optical burst switching network with optical buffer often achieves lower burst loss probability than dedicated buffer way in several different scenarios. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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