共查询到19条相似文献,搜索用时 109 毫秒
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疏导可以增加多播业务请求成功传输概率并提高光纤链路带宽利用率,但波分复用光网络中所有节点具有疏导能力则会增加网络造价和复杂度.本文研究了稀疏疏导网络中疏导节点选择策略,提出基于最小代价最大节点度数的疏导节点选择策略;根据疏导节点和非疏导节点功能差别,改进了稀疏疏导网络中多播请求的疏导传输方法.结合最小代价最大度数疏导节点选择策略和多播业务稀疏疏导传输方法,提出一种根据网络业务阻塞率限定值指标实现多播请求所需最少数目疏导节点的稀疏路由方法.仿真结果表明:在网络给定波长数和光收发器端口数目情况下,所提策略能够节约所需疏导节点数目并优化疏导节点位置,降低网络节点构造造价. 相似文献
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基于光纤光栅辅助耦合的WDM下话路研究 总被引:1,自引:0,他引:1
利用光纤光栅的反射特性和光纤耦合器的耦合特性,研究基于光纤光栅辅助耦合波分复用(WDM)下话路器.满足国际电信联盟(ITU-T)建议波长的WDM光信号从耦合器输入端口进入,其中与光栅中心反射波长一致的激光信号从耦合器的下话路端口输出,而其他波长的激光信号从耦合器输出端口输出,实现特定波长信号的下话路.选择中心波长分别为1554.248 nm,1555.859 nm,消光比为57 dB的两路光信号进行试验,光纤光栅的中心反射波长为1555.86 nm,实验结果表明,上述两路光信号分别从不对称光纤耦合器的输出端口和下话路端口输出,且在下话路端口输出光信号的消光比为48 dB. 相似文献
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光纤延迟线和可调谐波长转换器在光分组交换网络竞争解决结构中的性能分析 总被引:1,自引:1,他引:0
研究了光分组交换网络中的两种竞争解决方案.结合课题研究的进展,基于突发和非突发业务,对这两种竞争处理结构进行了深入分析,得出了几点重要结论,首先,在竞争处理上,对于非突发业务,光纤延迟线比可调谐波长转换器有效;而对于突发业务而言,可调谐波长转换器比光纤延迟线有效.其次,在突发业务下反馈式光纤延迟线结构(FFA)是一种较为理想的竞争解决结构,但对非突发业务而言,反馈式光纤延迟线和可调谐波长转换器结构(FFTA)在成本上和结构尺寸上比FFA要有效的多.随着平均突发长度的增加,FFTA中的可调谐波长转换器数目也要增加才能获得合理的分组丢失率。但无论是针对突发业务还是非突发业务,FFTA都是一种成本有效的竞争解决结构. 相似文献
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由于WDM网络中的传输和交换是以波长为粒度进行的。因此波长分配算法就成为光网络的研究热点。有效的算法可大大提高波长的利用率,并可充分挖掘WDM的带宽资源。介绍了WDM全光网络中静态和动态波长分配算法,尤其是结合大型网孔网络详述了几种动态波长分配算法。针对波长变换器在全光网络中的应用。提出了一种可以解决任意类型光网络的分层图算法,它可以一次性解决路由选择和波长分配问题,大大提高了该算法的效率。是未来光网络中非常有前景的一种波长分配算法。 相似文献
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光轨网络是一种能够利用成熟的光学器件实现带宽灵活分配和信息交换的新型网络.串扰是限制光轨网络的物理层性能及其扩展性的重要因素.本文讨论了典型的光轨网络节点中异频串扰和同频串扰的产生原因,理论分析了两者对光轨网络的物理层传输性能的影响.给出了3种串扰性能的评价方法.以密集波分复用技术为应用背景,分别搭建了器件隔离度为20 dB和30 dB的、具有3个节点5个波长且单波长速率为2.5 Gbps的光轨网络,仿真了串扰在光轨网络中的传播过程,并计算了光轨网络的误码率、功率代价和相对串扰.理论分析和仿真结果表明:光滤波器、解复用器和复用器是光轨网络中串扰产生的关键器件,且提高器件的隔离度等性能对于提高光轨网络的传输性能会有较显著的效果;在密集波分复用条件下,串扰对单波长速率为2.5 Gbps的光轨网络的误码率和功率代价具有显著的影响,从而限制了光轨网络实际可用的节点数目. 相似文献
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密集波分复用条件下的光轨网络串扰分析与仿真 总被引:1,自引:1,他引:0
光轨网络是一种能够利用成熟的光学器件实现带宽灵活分配和信息交换的新型网络.串扰是限制光轨网络的物理层性能及其扩展性的重要因素.本文讨论了典型的光轨网络节点中异频串扰和同频串扰的产生原因,理论分析了两者对光轨网络的物理层传输性能的影响.给出了3种串扰性能的评价方法.以密集波分复用技术为应用背景,分别搭建了器件隔离度为20dB和30dB的、具有3个节点5个波长且单波长速率为2.5Gbps的光轨网络,仿真了串扰在光轨网络中的传播过程,并计算了光轨网络的误码率、功率代价和相对串扰.理论分析和仿真结果表明:光滤波器、解复用器和复用器是光轨网络中串扰产生的关键器件,且提高器件的隔离度等性能对于提高光轨网络的传输性能会有较显著的效果;在密集波分复用条件下,串扰对单波长速率为2.5Gbps的光轨网络的误码率和功率代价具有显著的影响,从而限制了光轨网络实际可用的节点数目. 相似文献
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一种求解虚波长路径光网络波长资源优化问题的启发式算法 总被引:1,自引:0,他引:1
本文提出了一种虚波长路径光网络的启发式路由选择算法,它可以用来解决以最小化网络所需波长数目为目标的资源优化问题.该算法应用了基于最大概率路径的选路优化策略.对一个样例网络的数值分析结果表明该算法是有效的. 相似文献
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智能光网络中一种新型的分布式恢复方法 总被引:4,自引:4,他引:0
提出了一种基于固定备用路由和目的端触发的智能光网络中的分布式恢复方法,所选择的任一对源端节点和目的的端节点之间的固定备用路由包括该节点对之间的k条最短路径路由和基于部分链路无关的路由.目的端节点一旦探测到业务通道的失效将立即启动恢复进程,根据网络当前的资源使用情况,在这些备用路由中按照一定的次序选择一条恢复路由并为此分配一条可用的波长(对于没有波长变换器的光网络),然后将恢复通道的建立请求消息发送给该恢复通道的相关节点,这些相关节点可以锁定相关的网络资源,以避免来自其他恢复通道的竞争.所提出的算法增加了固定备用路由的数量,从仿真结果可以看出,该方法明显改善了失效连接的阻塞性能. 相似文献
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构建了一种五端口聚合物光路由器,由于四种不同半径的交叉耦合双环谐振器的谐振作用,该器件可完成二维平面内对四个信道波长的定点路由功能。由于聚合物材料和左右覆层材料具有较大的折射率差,四种微环的半径可小至14μm,波导模式振幅弯曲损耗小于10-4 dB/cm。当不同信道波长沿不同端口输入时,得到了波长与路由链路的关系。计算结果表明,各信道波长沿各路由链路的插入损耗为0.03~0.62dB,各路由链路on端口和其他off端口的最大串扰小于-39dB,器件的尺寸约为626μm×495μm。与已报道的硅光路由器相比,该聚合物器件具有相似的微环半径和封装尺寸,且由于零静态功耗、低串扰、低损耗和处理工艺简单、价格低廉等优势,该器件在光片上网络中具有潜在的应用价值。 相似文献
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In this paper dynamic routing and wavelength assignment strategies have been proposed for multiclass WDM optical networks. Multiclass optical networks provide multiple classes of services to the subscriber according to the requirement, which in turn increase operational profitability. Each class of service could be characterized by parameters like number of wavelengths, expected call holding time and average arrival rate of request. The proposed strategies have been analyzed and compared with existing strategies on the basis of blocking probabilities for multiclass traffic scenarios. Simulation results on different network topologies demonstrate that the performance of proposed strategies “Fixed shortest/alternate shortest path routing with wavelength reservation (FSASWR)” and “Fixed alternate shortest path routing with least priority wavelength assignment (FASPL)” are much better as compared to existing strategies. Proposed strategies minimize blocking probability of the multiclass network using limited number of wavelengths. 相似文献
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The blocking probability in wavelength-routed all optical networks is very important measure of performance of the network, which can be affected by many factors such as network topology, traffic load, number of links, algorithms employed and whether wavelength conversion is available or not. In this paper, we have proposed a mathematical model to reduce the blocking probability of the WDM optical network for wavelength-convertible networks. The model can be used to evaluate the blocking performance of any network topology also it can be useful to improve its blocking performance of the given network topology. The blocking probability variation of the network for a particular load (per link) has been studied based on the load variation and total number of wavelengths used in the network. This model gives good results for high load (per link). 相似文献
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This paper proposes a wavelength assignment method for all-to-all broadcast in wavelength reusable multi-carrier distributed (WRMD) wavelength division multiplexing (WDM) linear array and ring networks with wavelength reuse. An expression on the minimum number of wavelengths required to establish all-to-all broadcast is also derived for the networks. It is observed that one carrier regeneration per wavelength significantly reduces the number of wavelengths compared to that without carrier regeneration. The results also show that regenerating carriers more than once has little effect on the required number of wavelengths. 相似文献
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针对可利用的有限信道波长数对基于单纤连接节点的WDM星形单跳网容量限制问题,本文提出了一种有效的解决方案-波长重用.根据该方案,在信道波长数一定的条件下,至少可使网络所支持的节点数-网络容量扩大一倍;在网络节点数不变时,则可大大减少网络节点的排队时延,缓和网络中各通信节点对数据信道波长使用权的竞争矛盾,使网络吞吐量增加1~3倍,有效地改善网络性能.本文首先论述了该基于单纤连接节点的波长重用WDM星形单跳网结构,接着分析了网络的波长重用特性,进而对所要求的光放大器增益和输出功率进行了计算;最后计算了网络的最大节点数和最大信道波长数. 相似文献
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This article describes three network protection strategies for a single link failure using spare wavelengths in multiwavelength all-optical transparent networks. The use of spare wavelengths is shown to be effective and can be economical when a path restoration technique is used. It is also particularly suitable for high-bandwidth optical crossconnect nodes where the number of input and output ports are generally small. Based on the simulation results, the amount of redundancy required for fill protection is dependent on the protection approach employed. Two algorithms for finding and allocating spare wavelengths are introduced. The algorithms are based on the genetic and heuristic algorithms. 相似文献
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In IP over WDM networks, since there is a large bandwidth gap between a wavelength capacity and the actual bandwidth required by each user, it is necessary to multiplex low-rate traffic streams (LRSs) into lightpaths by traffic grooming. However, with the number of wavelengths increases, a large number of all optical (OOO) transmitting ports are consumed. Meanwhile, the multi-hop grooming with incorporating full-wavelength conversion capacity in each node requires too many optical-electrical-optical (OEO) ports inevitably. To solve theses problems, waveband switching and intra-band wavelength conversion are proposed. By integrating traffic grooming and waveband switching, this paper devises a new multi-granularity traffic grooming mechanism with the function of intra-band wavelength conversion. Based on the proposed mechanism and integrated grooming policy (IGP), a new heuristic routing algorithm called multi-granularity traffic grooming based on integrated auxiliary graph (MGIAG) is also proposed since the traffic grooming problem is NP-hard. Simulation results show that, compared to traditional integrated grooming algorithm (IGA), MGIAG can save more ports and obtain lower blocking probability. Compared to traditional single-hop traffic grooming algorithm (SHA), lower blocking probability and more savings in transmitting ports can be achieved by multi-hop grooming in MGIAG and IGA although they consume more OEO ports. 相似文献