共查询到19条相似文献,搜索用时 109 毫秒
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由于IP业务的指数增长以及WDM在传送网中的主导地位,将IP业务直接承载于WDM系统的IP ver DM光网络成为理想的选择。IP over WDM光网络可分为三个阶段,即:点到点IPoverWDM、IP0ver可重构WDM、IPover光交换的WDM。 相似文献
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光网络中引入全光交换技术可以无需进行光电光转换和电信号处理,使网络具备透明性,大大降低节点的复杂性和节点成本。多粒度交换节点减小了交换矩阵的规模,降低了交换矩阵的复杂性,是波分复用(WDM)网络节点发展的一个方向。随着正交频分复用(OFDM)技术的引入,带宽可变的节点技术得到了越来越广泛的关注。文章介绍了传统的基于波长的光交叉连接器(OXC)交换结构、多粒度交换结构,以及基于正交频分复用/单载波频分复用(OFDM/SCFDM)的节点交换结构,并通过实验对基于带宽可变的可重构的光分插复用器(ROADM)、OXC节点技术进行了验证。在实验中提出的基于子波带的交换结构中,节点容量达到了P比特量级。 相似文献
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WDM光网络的透明性问题 总被引:2,自引:0,他引:2
透明和不透明的光网络波分复用(WDM)光网络可以在光域进行信号的复用、传输、放大、选路以及恢复,正成为光通信领域研究的热点。WDM光网络支持多种信号格式,具有兼容性、经济性、可扩展性、可靠性,能为各种业务提供综合传送的物理平台。根据WDM光网络节点是否进行光信号的电处理,光网络可分为透明(Transaaren)网络和不透明(OPaque)网络两种类型。对于透明光网络,信号在从源节点到满节点传送过程中始终以光信号的形式进行,并在光域完成信号的再生、交换和波长变换,相应的网络单元结构如图匕所示、不透明光网络有两种实现形… 相似文献
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多粒度交换技术利用波带级路由以及光纤级路由,可有效降低光交叉连接器的复杂度。但多粒度交换增加了光网络的逻辑层次结构,使得网络中的路由与资源分配问题更为复杂,因此,在多粒度全光网中实现多层联合路由是提高网络性能的关键。本文对多粒度交叉连接结构进行了分析,并对多粒度全光网中的多层联合路由问题进行了研究。 相似文献
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多粒度光交叉连接能够提供光纤、波带和波长三种粒度的光交换,这一机制能有效提高交换性能,同时通过交换端口数的减少来降低光交换的成本。在这种交换结构中,需要在下层进行交换的信号需要首先经过上层的交换,或者所有信号都需要被不加区分地解复用出来进行交换,这造成了信号的过大损耗和失真,以及交换端口的浪费。我们在介绍了现有的研究以后,提出一种改进后的多粒度光交叉连接结构。通过仿真分析,可以看出这一新结构能够比其他结构更灵活地配置交换端口,同时能够避免不必要的信号损耗和失真,降低交换成本。 相似文献
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Van Breusegern E. Cheyns J. De Winter D. Colle D. Pickavet M. De Turck F. Demeester P. 《Selected Areas in Communications, IEEE Journal on》1996,14(5)
To efficiently support the highly dynamic traffic patterns of the current Internet in large-scale switches, we propose a new hybrid optical network design: Overspill Routing In Optical Networks (ORION). By taking advantage of the reduced (electronic) processing requirements of all-optical wavelength switching, the electronic bottleneck is relieved. At the same time, ORION achieves a level of statistical multiplexing comparable to the more traditional point to point WDM solutions, circumventing the bandwidth inefficiencies of all-optical wavelength switched networks, caused by dynamic traffic patterns. The result is a true hybrid optical network design, forming a bridge between these two switching concepts. In this paper the generic concept of ORION is described. An example node design, based on current advanced optical technologies, is described in detail. The ORION concept is also evaluated, comparing it with its two composing technologies, optical wavelength switching and point to point WDM, as well as a third, more trivial, hybrid one, through several case studies. 相似文献
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对基于半导体光放大器(SOA)交叉增益调制(XGM)效应的全光波分复用一光时分复用(WDM—OTDM)转换后的两路时分复用输出信号的消光比(ER)特性进行了分析。研究了两路波分复用的输入抽运光和探测光的功率、波长、抽运光的消光比、数据速率以及半导体光放大器的偏置电流、腔长和模场限制因子对转换信号消光比的影响。模拟结果表明,增大抽运光输入功率,选择长波长抽运光,可以增加转换光相应信道消光比,但减小了相邻信道的输出消光比;增加抽运光消光比,可以提高转换光消光比,但各个信道增长幅度不同;减小探测光输入功率,选取短波长探测光波长,增加半导体光放大器的腔长和模场限制因子以及大的偏置电流可提高转换光消光比;对于两路或多路波分复用信号转换时分复用信号的过程中,一定要考虑转换光每个信道消光比的均衡。 相似文献
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The multi-hop multi-rate wavelength division multiplexing ring 总被引:1,自引:0,他引:1
Cerutti I. Fumagalli A. Tacca M. Lardies A. Jagannathan R. 《Lightwave Technology, Journal of》2000,18(12):1649-1656
Transparency of the optical layer offers the possibility to design a network that operates at varying transmission bit rates. While variable bit rate interfaces are being tested and will soon provide the possibility to optimally select the transmission rate for each optical channel, the potential advantages of relying upon multiple transmission rates in the optical network have yet to be fully explored. In this paper, we define the concept of multi-hop and multi-rate (M&M for short) network in which the tributary signal is transmitted over a concatenation of optical channels, with each optical channel operating at its own transmission rate. The optimal rate of each optical channel is determined by a number of factors including the end node's interface, amount of multiplexed traffic and cost of the network components. The potential advantages provided by the M&M network when compared to first generation optical networks (i.e., SONET/SDH), to single- and multi-hop (constant bit rate) optical networks, are discussed in general and demonstrated numerically in a WDM ring. Presented results show that the network cost reduction achieved by the M&M design is a function of the cost ratio between the optical bandwidth (wavelengths) and the optical terminals 相似文献
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We discuss design considerations for wavelength division multiplexing (WDM)-based packet networks. In the near term, such networks are likely to consist of WDM links connected using some form of electronic multiplexing. The focus of this article is on the joint design of the electronic and optical layer with the objective of simplifying the network and reducing the protocol stack. To that end, we discuss the benefits of optical flow switching, network reconfiguration, traffic grooming, and optical layer protection. We also discuss the state of all-optical packet networking with particular focus on local area network technology 相似文献
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In this article we investigate the problem of efficiently provisioning connections of different bandwidth granularities in a heterogeneous WDM mesh network through dynamic traffic grooming schemes under traffic engineering principles. Due to the huge amount of traffic a WDM backbone network can support and the large geographic area it can cover, constructing and upgrading such an optical WDM network can be costly. Hence, it is extremely important for network operators to apply traffic engineering strategies to cost-effectively support different bandwidth granularity services using only the appropriate amount of network resources. This requires an optical WDM network to have multigranularity switching capability, and such a network tends to be a multivendor heterogeneous network. However, WDM network heterogeneity increases the difficulty and challenge of efficient traffic provisioning. In this article we present different TE issues that need to be carefully considered in such an optical WDM network, and propose possible solutions and extensions for the generalized multiprotocol label switching optical network control plane. We extend an existing generic graph model to perform efficient traffic grooming and achieve different TE objectives through simple shortest path computation algorithms. We show that our approach is very practical and very suitable for traffic engineering in a heterogeneous multigranularity optical WDM mesh network. 相似文献
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We report in this paper the architectural design and implementation of all-optical packet networks. Using photonic switches to route information, an all-optical network has the advantages of bit rate, wavelength, and signal format transparencies. Within the transparency distance, the network is capable of handling a widely heterogeneous mix of traffic. We will describe our research on the implementation of all-optical backbone switches. The switch components including frame synchronizers, frame delineation units, frame header over-writing units, wavelength converters, frame concentrators, and WDM buffers were constructed at 2.5 Gb/s. Their subsystem and device structure as well as preliminary performance are reported. 相似文献
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《Optical Fiber Technology》2002,8(1):43-70
To accommodate the explosive packet-based data traffic in WDM networks, intelligent optical routing and switching are required in optical transport networks. Optical multiprotocol label switching networks emerged to meet this demand. In this paper, different schemes for implementing an OMPLS network are introduced. An optical MPLS network using OOC/wavelengths as labels is proposed. Based on an all-optical code converter, the architecture of the optical core router is demonstrated. The fundamental limits on scalability of the proposed core router, namely the label capacity, and the blocking probability of the label switched path setup are investigated, and closed-form solutions are derived. 相似文献
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Huan-Lin Liu Xiang Xue Yong Chen Qiang Fang Sheng Huang 《Photonic Network Communications》2013,26(2-3):95-102
With the growth of multi-granularity multicast applications, there comes into being a huge gap between the bandwidth of a wavelength provided and a multicast traffic required in the wavelength division multiplexing (WDM) networks. The dynamic multicast traffic-grooming is an effective way for WDM networks to improve the wavelength utilization and decrease the traffic blocking probability. A novel switching node architecture with the multicast switching matrix and traffic-grooming fabric is studied in the paper. Then, an efficient dynamic multicast traffic-grooming algorithm is proposed for the architecture. According to the ratio of network available grooming port number to network transceiver number, the proposed algorithm estimates whether the traffic-grooming port is a scarce resource for input traffic and chooses the appropriate grooming strategy. If the traffic-grooming port is scarce, the minimized use grooming port strategy is designed for the coming traffic. On the contrary, the minimized use node transceiver strategy is applied for the coming traffic. Simulation results show that the proposed algorithm can groom traffic efficiently with low blocking probability and high network throughput constraint by limiting number of node transceivers and grooming ports. 相似文献
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Advances in photonic packet switching: an overview 总被引:26,自引:0,他引:26
The current fast-growing Internet traffic is demanding more and more network capacity every day. The concept of wavelength-division multiplexing has provided us an opportunity to multiply network capacity. Current optical switching technologies allow us to rapidly deliver the enormous bandwidth of WDM networks. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this article we present some of the critical issues involved in designing and implementing all-optical packet-switched networks 相似文献