基于多重路由算法的波分复用网络通讯分析与研究

由于波分复用网络近年来蓬勃发展,在网络使用多重传输通讯可提供高质量的服务应用,如视频会议等。本文架构于稀疏光功率分裂的波分复用网络动态多重传输路由,解决架构于波分复用网络多重传输路由的选择问题。     

光通信网络中路由与波长分配的算法研究

光通信网络作为下一代网络的主要网络之一,在整个通信网中起着至关重要的作用。目前光通信中主要是采用基于DWDM(密集波分复用)技术组成的光网络,随着波分数量的增加,DWDM网络中的路由与波长分配问题显得十分重要,需要有一种有效的算法来使有限的波长资源得到充分地利用。本文根据原有的数学分析模型,提出了一种分层图模型,并根据此模型提出了一种用来解决DWDM网络中出现的波长分配问题的一种算法,并通过计算机仿真来表明此算法提高了波长资源的利用率,降低了网络的阻塞率。     

一种严格非阻塞Clos型波分复用光置换网络

波分复用光交换网络设计中的一个重要问题是如何在提供完全连接能力的同时保持最低的硬件代价.这里采用波长交换原理,提出一种能同时完成空间交换和波长转换的交叉开关,并将其作为基本模块构造出严格非阻塞Clos型波分复用光置换网络.与现有网络相比,该网络不需要额外的波长转换级,减小了信号衰减;降低了整体硬件代价,在空间交换代价和波长转换代价之间取得了很好的平衡,并具有较好的扩展性.     

发展中的光互联网技术

分析了光互联网的发展和应用情况,介绍了波分复用、光传输网络、WDM网络体系结构及光经联网多协议模型等相关技术。     

基于改进PCNN算法的光网络RWA问题的研究

针对波分复用光网络在动态业务下的路由和波长分配问题,本文将一种改进的脉冲耦合神经网络(PCNN——Pulse Coupled Neural Networks)算法引入到光网络路由选择中,并将波长分配与分层图模型相结合,通过改变PCNN神经元的点火方式以及控制自动波的传播时间模拟路径代价,使得网络路由选择具有了PCNN的并行处理特性。结合波长分配算法进行仿真,结果表明,本算法与传统的最短路径算法相比,总能得到全局最优解且计算量小,降低了网络的呼叫阻塞率,提高了对网络资源的利用。     

并非专用——北电网络谈光技术在企业网的发展前景

通常一说到光网络技术的应用,更多地是与运营商的网络联系起来,OFDM(正交频分复用)、DWDN(密集波分复用)、RPR(弹性分组环Resilient Packet Ring)等专有名词好像与企业网毫不相干。其实不然,随着企业网中用户数据量的增加,企业网规模的扩大,以及企业网用户在向着网络融合的趋势发展下,作为一种传输层的网络技术,光网络产品除在运营商网络中广泛应用之外。已经成功应用于银行、电力、教育等行业中,光     

一种用于并行计算系统的分级光环互连网络

介绍了大规模并行计算的一个新互连网络——分级光环互连,适用于多处理器与多计算机的可升级网络。分级光环互连由一个衡量无阻塞、容错的单跳可升级互连拓扑组成,并通过波分多址技术充分地利用了光纤的TeraHz带宽。此光网络融合了分级环的互连节点接口简单、节点度恒定、容错等各种吸引人的特征以及光通信的各种优点。提出了分级光环互连拓扑,分析了其结构特征并描述了光设计的方法,导出了一个简短可行的分级光环互连研究。     

基于博弈均衡的WDM光网络动态恢复策略

提出一种基于博弈论和D*思想的动态均衡启发式算法，求解波分复用(WDM)光网络中波长级恢复问题。算法将网络中的各边代价与当前波长使用情况综合考虑，运用博弈论原理动态构建估计函数，实现了WDM光网络的高效恢复。仿真结果表明，该算法能有效地降低光路阻塞，提高恢复率，其快速和智能特性能够满足恢复时间的要求。     

基于波长选择型可重构光分插复用设备的IP网络的传输长度设计

针对高速大容量波分复用(WDM)网络在多点故障、变更的情况下,运行效率低、维护成本高的问题,提出使用可重构光分插复用设备(ROADM)元件来构建灵活网络.首先,给出了所用的5节点网络配置模型;然后,研究了在动态网络条件下使用ROADM的光网络损耗与传输长度间关系,提出网络传输长度设计流程;其次,基于ROADM搭建一个5节点双向光纤环路实验网络,测量了光损失特性;最后,分析实验结果,得出损耗计算值与光纤实装损耗测量值近似相等(相差0.8 dB),验证了设计的可行性,保证了节点间的可靠传输.     

浅析现代网络的通信技术

目前,通信业处于急剧变革的时代,业务的发展导致电信网产生巨大的变革,未来的业务发展也对传输网络的技术提出了新的要求。本文主要分析阐释了“多业务传送平台（MSTP）、自动交换光网络（ASON）、城域波分（DWDM）、光传送网OTN、末端接入技术”等五种主流技术及它们的应用。     

基于WDM的全光网结构与应用技术

介绍了基于波分复用（WDM）的全光网的概念、光交换技术及特点,讨论了WDM全光网的网络结构及关键部件,并给出一个基于WDM技术的ATM光交换机结构。     

Memory and Network Architecture Interaction in an Optically Interconnected Distributed Shared Memory System

This paper develops a performance model of an optically interconnected parallel computer system operating in a distributed shared memory environment. The performance model is developed to reflect the impact of low level optical media access protocol and optical device switching latency on high level system performance. This enables the model to predict the performance impact of supporting distributed shared memory with different address allocation schemes and media access protocols. The passive star-coupled photonic network operates through wavelength division multiple access. Two media access protocols are examined for this WDM network, both are designed to operate in a multiple-channel multiple-access environment and require each node to possess a wavelength tunable transmitter and a fixed (or slow tunable) receiver. A semi-Markov model has been developed to study the interaction of the distributed shared memory architecture and the two access protocols of the photonic network. This analytical model has been validated by extensive simulation. The model is then used to examine the system performance with varying numbers of nodes and wavelength channels and varying, memory and channel access times.     

A class of highly scalable optical crossbar-connectedinterconnection networks (SOCNs) for parallel computing systems

A class of highly scalable interconnect topologies called the Scalable Optical Crossbar-Connected Interconnection Networks (SOCNs) is proposed. This proposed class of networks combines the use of tunable Vertical Cavity Surface Emitting Lasers (VCSEL's), Wavelength Division Multiplexing (WDM) and a scalable, hierarchical network architecture to implement large-scale optical crossbar based networks. A free-space and optical waveguide-based crossbar interconnect utilizing tunable VCSEL arrays is proposed for interconnecting processor elements within a local cluster. A similar WDM optical crossbar using optical fibers is proposed for implementing intercluster crossbar links. The combination of the two technologies produces large-scale optical fan-out switches that could be used to implement relatively low cost, large scale, high bandwidth, low latency, fully connected crossbar clusters supporting up to hundreds of processors. An extension of the crossbar network architecture is also proposed that implements a hybrid network architecture that is much more scalable. This could be used to connect thousands of processors in a multiprocessor configuration while maintaining a low latency and high bandwidth. Such an architecture could be very suitable for constructing relatively inexpensive, highly scalable, high bandwidth, and fault-tolerant interconnects for large-scale, massively parallel computer systems. This paper presents a thorough analysis of two example topologies, including a comparison of the two topologies to other popular networks. In addition, an overview of a proposed optical implementation and power budget is presented, along with analysis of proposed media access control protocols and corresponding optical implementation     

基于WDM网络的光分组交换结构

介绍了基于波分复用（WDM）全光网的相关技术,提出了光分组交换机的总体结构及性质,并给出一个采用波长路由选择技术实现的光分组交换模型。     

A flexible optical switch architecture for efficient transmission of optical bursts

In this paper, we propose a new optical switch architecture for optical WDM networks. Flexibility and efficiency in terms of controlling and utilizing optical power are key features of the architecture. The architecture uses switching components which have increased flexibility of how optical power received on an input port is managed when switching optical signals. Like the traditional optical switches, optical power can be directed towards one output port only. Further, unlike the traditional switches, on need basis, the power can be split on a desired sub-set of output ports, thus reducing power wastage on unwanted ports. Such split power can be directed fully towards a single output port as and when it is needed. This flexible and efficient power management makes the architecture a potential candidate for optical networks with its usage in several dimensions. The dimensions include (1) switching methods such as circuit level switching and bursty level switching, (2) network types such as core, metro, and access networks, (3) support for technologies such as Light-trails and Light-trees, and (4) support for functionalities such as survivability and multicasting with new features. Importantly, there is potential that the architecture enhances adaptability based on the needs, and it supports co-existence and seamless integration of different environments.In this paper, our focus is on investigating bursty level switching using the proposed switch architecture. We use the flexibility of the switch and adopt a new switching method for data bursts. This switching method is efficient for switching bursts while introducing new challenges. Unlike the traditional switching method, it switches bursts arriving on an input link with zero (or very small) time gaps to different output links in certain scenarios. Further, it also switches bursts from different input links to the same output link when they arrive with zero (or very small) time interval. Adopting such switching approaches has potential benefits in terms of delay-load performance and blocking performance. While the bursts are switched from the same input link to different output links in this approach, it creates some unwanted signals. We investigate scenarios in which the unwanted signals create any problems and this poses some challenges. To address such challenges, we develop a transmission protocol. We investigate the performance of our solutions using simulation studies and verify the two significant gains: (1) networks’ capability to sustain traffic loads up to the maximum level in terms of the delay-load performance, which is similar to the performance seen for hypothetical ideal switches with zero switching time, and (2) improved blocking performance.     

A Novel Multistage Network Architecture with Multicast and Broadcast Capability

In this paper, a new class of optical multistage interconnection network (MIN) architecture is presented, which is constructed utilizing a modularization approach rather than the traditional recursive or fixed exchange pattern methods. The modified architecture consists of an input module, an output module, two point-to-point (PTP) modules, and one modified multicast/broadcast (M/B) module(s). We also implement the multicast/broadcast module with WDM technique, which reduces the hardware cost required for multicast and the re-computation cost for a new connection. We show that it has the best application flexibility and provides multicast function without imposing significant negative impacts on the whole network. A new multicast connection pattern is also proposed in this paper, which makes it practical and economical to apply amplification in space-division networks. Compared with existing multicast architectures, this new architecture with Dilated Benes PTP modules has better performance in terms of system SNR, the number of switch elements, and system attenuation in point-to-point connections. Moreover, the multicast/broadcast module adopts wavelength division multiplexing (WDM) technique to increase its multicast/broadcast assignment. As a result, given m available distinguished wavelengths, one M/B module can support at most m M/B requests at the same time. The new proposed M/B module with WDM is more practical and economical to apply amplification in space-division networks.     

构建网络的新方法：基于环路的混合交换光网络*

为了能够更好地支持突发性数据业务,提出了一种新型网络交换结构——基于环路的混合交换光网络（cyclebased hybrid switching optical networks,CHSON）。该网络结合了光电路交换（OCS）和光突发交换（OBS）两种交换技术,不仅可以有效地降低网络节点的分组转发压力,而且能够较好地承载突发性数据业务。首先介绍了CHSON的网络结构和虚拓扑设计,然后阐述了节点设计及其执行流程。仿真表明,CHSON具有比OCS网络更低的丢包率,而且在丢包率和平均分组延时方面,CHSON较     

Computational intelligence in photonics technology and optical networks: A survey and future perspectives

The continuous growth of broadband communications, multimedia services and Internet is absolutely related to the deployment and operation of optical networks. Despite optical fibers’ enormous physical bandwidth the development of optical networks for today’s advanced, reliable and guaranteed-type services, require an efficient management of the bandwidth together with an orthological and careful use of optical components given their high manufacturing cost. These requirements have lead to the need for sophisticated photonic devices and to optical networks’ implementations of increased functionality and associated thus complexity. For the efficient consideration of those problems different design and optimization techniques have been applied to date. However, as the complexity increases, the use of computational intelligence (CI) in those problems is becoming a unique tool of imperative value. In this paper we review in a unified approach the applications of CI starting from the physical layer and ending to services layer, given that here there is a strong relation and unique interplay between components’ technology and network issues, being sharing the common target of physical bandwidth’s efficient utilization. The applicability of different CI classes (genetic algorithms and evolution strategies, fuzzy systems, and artificial neural networks) in optical wavelength division multiplexing (WDM) networks is identified and evaluated. Furthermore specific optical networks’ optimization problems are categorized. Being a rapidly growing area, new trends, such as evolutionary game theory, in understanding and design of large scale Optical Network are also identified and discussed. The paper seeks to review the aforementioned areas, identify new problems and trends, triggering this way new research efforts for interdisciplinary cooperation between researchers.     

Dynamic routing and resource allocation in WDM transport networks

This contribution concentrates on dynamic routing in Wavelength Division Multiplexing (WDM) networks. It is shown that a strategy based on pre-calculated alternatives and an adaptive dynamic path search performs very well over a wide load range. Moreover, specific effects for the impact of resource allocation strategies in photonic WDM networks are highlighted, especially the influence of wavelength converter usage strategies in networks with partial conversion. The paper also investigates the way non-Poisson traffic behaviour affects performance of routing strategies and presents how the results from dynamic routing investigation can help to optimise the network planning process.     

Building Ultralow-Latency Interconnection Networks Using Photonic Integration

Ultralow-latency interconnection networks have become a necessity in modern high-performance computing systems. recent advances in photonic integration technology are paving the way for a disruptive step in the design of these networks. We present SPINet, an optical interconnection network architecture designed for implementation using photonic integration, providing an end-to-end photonic path while completely avoiding optical buffering. SPINet resolves contentions through message dropping, but facilitates message recovery using a novel physical-layer acknowledgment protocol.