共查询到19条相似文献,搜索用时 93 毫秒
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WDM光传送网的选路和波长分配算法 总被引:10,自引:1,他引:9
文章综述了波分复用(WDM)光传送网的选路和波长分配(RWA)算法;考虑了两种需求情况一种是从建立光路的需求出发,另一种是从运送分组业务的需求出发;还概述了RWA设计中要考虑的附加问题,包括波长变换、抗毁和服务策略. 相似文献
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研究了动态业务下,无波长变换的波分复用全光风采用固定选路时的波长分配问题,提出了一种中心式的波长分配算法-最小影响算法。该算法能精确地描述某个波长的分配对全网状态的影响,因而能够更有效地使用网络资源。计算机仿真表明,如果用阻塞概率来衡量,该波长分配算法优于文献中已有的典型算法。 相似文献
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波分复用光传送网及其关键器件技术 总被引:1,自引:0,他引:1
近年来通信流量增长非常快,尤其是以Internet为主的数据通信流量出现了爆炸式增长,保守的估计是每六个月翻一番。通信流量的急剧增长给传送网带来了很大的压力,许多光纤网络容量的使用率达到了70-80%,在某些情形严重的路由上,连备用容量也已经耗尽了。这迫使网络公司增加网络带宽,减小网络的拥塞。增加带宽的方法主要有: 相似文献
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研究了动态业务下,采用固定选路和备用选路的波分复用光传送网中的波长分配问题.提出了一种新的波长分配算法,新算法在已市算法的基础上进行了改进,与已有算法相比,该算法能更精确地描述波长分配对全厨状态的影响。计算机仿真表明,如果用阻塞率来衡量,该波长分配算法优于文献中已有的波长分配算法。 相似文献
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目前网络承载业务的趋势是以IP为中心的数据业务,从而促进了以WDM光网络向高速和宽带多波长的应用和普及,为了进一步提高网络的性能并提高资源利用率,出现了光网络控制面技术.路由选择与波长分配问题是WDM光传输网络控制面中非常重要的问题之一.目前实际应用最广泛的波长分配算法是First-Fir(FF)算法.本文基于FF算法,研究动态业务下波分复用光网络在固定选路下的波长分配问题,提出了一种新的波长分配启发式算法——Joint First Fit.计算机仿真试验表明,与常用的FF算法相比,该算法显著的降低了网络呼叫阻塞率,有利于提高网络资源的利用率. 相似文献
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Nilesh M. Bhide Krishna M. Sivalingam Tibor Fabry-Asztalos 《Photonic Network Communications》2001,3(3):227-236
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. 相似文献
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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. 相似文献
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Conventional optical wavelength division multiplexing (WDM) networks calls for optoelectronic conversion for each wavelength in every node plus a large management effort for proper packet routing. All-optical networks are still unavailable. Here, a new architecture is described where the optical transport is done without conversions (except at extreme nodes), and with minimal routing management effort. The present basic mechanism is, firstly, to gather (at any source node) the packets demanding for a certain destination node K. Secondly, all these packets are modulated onto wavelength K. Next, the wavelength is routed towards node K by passive directional devices. As other source nodes reuse wavelength K, an anti-collision mechanism is presented. This mechanism uses very economic and widely available components. The present arrangement seems to be pre-wired, conveying packets from source to destination nodes almost automatically. The present arrangement is simpler and far more economical than (G)MPL()S arrangements, for instance. Additionally, the present system does not demand for expensive wavelength conversions or central protocols. The disadvantage over (G)MPL()S is that the present arrangement limits its maximum number of operational nodes to the number of wavelenghts WDM is able to support. 相似文献
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Xiangqing Tian Xiaoqiong Qi Qiongfang Ma Xiaoping Zhang 《Photonic Network Communications》2006,11(3):271-276
A new design scheme for a distributed algorithm for routing and wavelength assignment (RWA) is developed in this paper, and
the communication rules between the nodes to exchange signaling packets are discussed. The Adaptive-Alternate-Routing-Least-Load
(AARLL) algorithm is implemented in the distributed scheme for the first time. Under dynamic traffic circumstances, the influence
of the race condition, which does not exist in centralized scheme, on the network performance is analyzed and the analyzed
results show that the race condition has a major impact on network performance only under light traffic load, while under
medium and heavy traffic load the impact is very small. To analyze the performance loss caused by adopting the distributed
algorithm for RWA, the capacity loss factor (CLF) is introduced and the calculated results show that CLF does not exceed 6%
under medium traffic load. 相似文献
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在WDM光网络中,在给定一组连接请求后,需要为之建立路由并分配波长,这被称为路由和波长分配问题(RWA)。由于当前光网络中的业务呈现爆炸式的增长,而光网络中的可用资源却是有限的,因此如何使用合理的RWA算法来优化网络资源的利用就显得尤为重要。目前已有很多文献提出了基于各种优化目标的RWA算法,也都通计算机仿真的方法测试和评估了算法的性能。计算机仿真是进行算法性能评估的主要手段,但是关于算法仿真的实现,—般的文献都涉及的很少,本文主要研究了WDM光网络中动态RWA算法计算机枋真的实现。 相似文献
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部分共享波长转换光网络动态路由的改进算法 总被引:4,自引:4,他引:0
提出了一种应用于部分共享波长转换(PWC)的波长路由光网络(WRON)中的基于节点阻塞的动态路由算法,它不需要共享复杂的波长转换信息,而是将各节点的阻塞特性考虑到路由过程中。为评价算法性能,在14节点的国家科学基金网(NSFNET)拓扑中进行了仿真。结果表明,新的路由算法显著改善了网络的阻塞性能和建路失败的概率,尤其是随着网络负载的降低,网络性能的改善更显著。 相似文献