全光网络管理信息传输研究

文章介绍了采用波分复用技术传输和波长路由的全光网络,然后针对它的管理特征提出了三种网管信息传输模式:寄生传输、OSC传输和光树传输;最大论述了光树传输将成为光网的一个技术发展趋势。     

新一代的光纤通信网--全光网

综述了全光网的基本概念，并介绍了全光网的网络拓扑结构、波长路由等关键技术和全光网的发展趋势。     

WDM网络分布式物理损伤感知RWA算法

随着传输速率的不断升级,在透明传送过程中,各种损伤的积累会对光信号的质量造成严重影响,因而不能保证高QoS(服务质量)地传输信号.文章提出一种物理损伤感知的分布式RWA(波长路由分配)算法,将物理层传输质量评估分布在中继段路由和波长信道中,分别由损伤感知路由、波长通道传输质量排序和按优先级分配3部分构成.仿真实例证明了...     

WDM网络中的动态路由波长分配

本文对 WDM全光网中的路由波长分配 (RWA )问题进行了分析和研究 ,详细阐述了面向各类业务的路由波长分配策略以及各种动态路由波长算法的设计思想 ,并对各种算法的性能以及时间复杂度等参数进行了分析 ,并在典型拓扑上进行了仿真     

新一代光纤通信网--全光网

本文综述了全光网的基本概念，并介绍了全光网的网络拓扑结构、波长路由等关键技术和全光网的发展趋势。     

自动交换光网络中路由问题的研究

在介绍自动交换光网络(ASON)路由体系结构的基础上,通过仿真分析,总体的衡量和把握了路由策略对网络性能产生的影响,其中考虑了波长转换能力和备选路由数等路由参数的影响.     

对智能光网的关键技术的研究

在网络技术日益提高的背景下,智能光网技术应运而生,并取得了理想应用效果,如进一步提高了网络资源的利用率。为推动智能光网技术的进一步发展,本文针对智能光网的关键技术进行研究,首先概述了智能光网的概念及优点,然后重点讨论了智能光网的关键技术,主要包括路由选择和波长分配技术、传送技术、控制平面技术等。     

多波长全光网络的新进展（上）

以波分复用技术为基础的多波长透明全光网络的研究是当今光通信领域中的研究热点，多波长全光网络的现场试验集中反映了与此有关的各个领域的研究水平和实用化进展程度。在简要回顾国际上光网技术的研究活动以后，本文重点分析归纳了具有代表性的三个光网试验项目：多波长光网、国家透明光网络和ＷＥＳＴ，包括网络结构、关键技术、试验情况和结果分析。     

全光网——光通信的发展方向

全光网(AON,all-opticalnetwork)以波长路由光交换技术和波分复用传输技术(WDM)为基础,它的网络节点由光分插复用器和光交叉连接器构成,能在光域上实现高速信息流的传输、交换、路由和故障恢复等功能。光交叉连接器(OXC)与光分插复用器(OADM)是全光网中最重要的网络器件,是真正实现全光网关键性功能的必要前提,也是目前国内外光通信器件厂商研究和开发的热点。本文结合全光网的发展,介绍了光交叉连接器(OXC)、光分插复用器(OADM)与掺饵光纤放大器(EDFA)的基本原理以及全光网的交换技术,对光通信网和传统通信网进行了比较与讨论,并介绍了我国和国外在全光通信网上的发展状况。     

WDM网络中的动态路由波长分配

本文对WDM全光网中的路由波长分配(RWA)问题进行了分析和研究，详细阐述了面向各类业务的路由波长分配策略以及各种动态路由波长算法的设计思想，并对各种算法的性能以及时间复杂度等参数进行了分析，并在典型拓扑上进行了仿真。     

Toward wide-scale all-optical transparent networking: the ACTSoptical pan-European network (OPEN) project

The European ACTS project optical pan-European network (OPEN) aims at assessing the feasibility of an optical pan-European overlay network, interconnecting major European cities by means of a mesh of high-capacity optical fiber links, cross-connected through transparent photonic nodes. Both the transmission links and the routing network elements rely on wavelength division multiplexing (WDM) all-optical technologies, such as wavelength translation. This paper presents results obtained in the following domains covered within the project: network topology considerations (optimization and dimensioning); network physical layer simulation; fabrications of packaged functional modules based on advanced optoelectronic devices; laboratory demonstrations of N×10 Gb/s transmission and routing; feasibility of an optical time division multiplexing/WDM (OTDM/WDM) interface; and the field implementation of a 4×4 multiwavelength crossconnect prototype, featuring all-optical space and wavelength routing. This implementation was realized in two cross-border field trials, one conducted between Norway and Denmark and the other between France and Belgium. The final results of the Norway to Denmark field trials are presented, featuring the successful cascade of three wavelength-translating optical crossconnects (OXCs), along with the transmission over 1000 km of a mix of standard/submarine cable links for four channels at 2.5 Gb/s     

Quality of service aware fuzzy dynamic routing and wavelength assignment technique in all optical networks

In this paper, a novel fuzzy dynamic routing and wavelength assignment technique is proposed for a wavelength division multiplexing optical network to achieve the best quality of network transmission. This paper proposes a novel quality of service aware fuzzy logic controlled dynamic routing and wavelength assignment algorithm (QoS-FDRWA), where the optimum path is chosen by a fuzzy rule-based inference system. The proposed fuzzy routing technique incorporates optical network transmission attributes such as latency, physical length of the link, data packet loss, number of hops, and wavelength availability status in the path.     

Distributed optical control plane for dynamic lightpath establishment in translucent optical networks based on reachability graph

In transparent optical networks, physical layer impairments (PLIs) incurred by non-ideal optical transmission media accumulate along an optical path, and the overall effect determines the optical feasibility of the lightpaths. In addition, transparent optical networks suffer from inefficient wavelength utilization, as a connection request may be rejected because of non-availability of a common wavelength on all the links along the chosen route. To increase optical reach, resource utilization, and average call acceptance ratio (and hence revenues), network operators are resort to translucent optical networks. In these networks a limited number of regenerators are placed at a selected set of nodes. In this scenario development of an optical control plane which is aware of PLIs, location and number of regenerators, is of paramount importance for on-demand lightpath provisioning. In this paper, we propose a novel approach of constructing a reachability graph of the physical network considering PLIs and regenerators. If there is no transparent path in the physical network, we route the connections with multiple transparent segments on the reachability graph. We propose efficient mechanisms and corresponding GMPLS protocol extensions for impairment and regenerator aware routing and wavelength assignment (IRA-RWA) in translucent optical networks. The simulation results suggest that our proposed approach together with LSP stitching signaling mechanism is feasible to implement and close to deployment.     

用波分复用技术设计和实现的双波长光纤环网

本文设计和实现了具有PCI总线峰值带宽传输能力的光互连网络接口卡。采用可编程门阵列实现硬件路由和同步流水线传输以减小数据包在网络中的通信延迟。为扩展网络规模,采用波分复用技术实现了双波长环网。通过无源光学器件实现双波长信号和合波和分束,通过探测器选择接收不同波长的光信号以实现波长路由。该网络结构扩展为多波长环网。     

Optical cross-connect system in broad-band networks: system conceptand demonstrators description

A network robust to future evolution in network topologies or transmission formats and bit rates, which would be achieved by introducing an all-optical transparent layer in the transport network hierarchy is considered. The transparency would permit use of physically common fiber lines and nodes for different transmission hierarchies and/or formats. A transparent network could be achieved by combining photonic switching with electronic switching technology in the network nodes. A combination of wavelength routing and space-division switching in the optical layer would increase the capacity, as well as the flexibility in a network, allowing routing with higher granularity within the optical layer. Two optical cross-connect demonstrators have been set up. One demonstrates protection switching and restoration of traffic in a future transport network, and the other demonstrates routing of subscriber signals to different service switches in a local exchange. Space switches, tunable lasers and filters are the key technologies used to obtain enhanced flexibility     

Impact of transmission performance on path routing in all-opticaltransport networks

The impact of transmission related issues on the routing strategies for transparent all-optical wavelength division multiplexed (WDM) transport networks is analyzed in this paper. Three different categories of routing algorithms are analyzed: algorithms based on the wavelength path (WP) strategy, based on the virtual wavelength path (VWP) strategy and requiring only a limited number of wavelength converters in the network partial virtual wavelength path (PVWP). It results that the PVWP allows a saving in network devices with respect to the WP similar those permitted by the VWP also attaining transmission performances near those attained by the WP that are quite better that those attained by the VWP     

Sparse Regeneration in Translucent Wavelength-Routed Optical Networks: Architecture,Network Design and Wavelength Routing

In this paper we study an alternate network architecture, called translucent network, to the fully transparent and fully opaque network architectures. In a translucent wavelength-routed optical network, a technique called sparse regeneration is used to overcome the severe lightpath blocking due to signal quality degradation and wavelength contention in a fully transparent network while using much less regenerators than in a fully opaque network. In this paper, we present a node model and a network model that perform sparse regeneration. We address the problem of translucent network design by proposing several regenerator placement algorithms based on different knowledge of future network traffic patterns. We also address the problem of wavelength routing under sparse regeneration by incorporating two regenerator allocation strategies with heuristic wavelength routing algorithms. We compare the performance of different regenerator placement algorithms and wavelength routing schemes through simulation experiments. The benefit of sparse regeneration is quantitatively measured under different network settings.This work was supported by NSF grants (ANI-0074121 and EPS-0091900).Portions of this work have appeared in the Proceedings of the OSA Optical Fiber Communications (OFC 1999) Conference [6] and the Proceedings of the IEEE Global Telecommunications (GLOBECOM 2001) Conference [12].     

A distributed ant-based algorithm for routing and wavelength assignment in an optical burst switching flexible spectrum network with transmission impairments

This work describes a distributed algorithm inspired by ant colony optimisation for a solution to the problem of dynamic routing and wavelength assignment with wavelength continuity constraint in optical burst switched networks. The evaluation was conducted in a wavelength division multiplexed network environment with limited number of wavelength channels and in a flexible spectrum network environment undergoing transmission impairments. The simulations in the flexible spectrum network environment aim to replicate the effects of both linear and nonlinear physical layer impairments. Under these effects, an optical burst control packet could be lost during traversal of the network with no measure in place to notify the network of the loss or to free up optical resource reservations. The optical burst switching acknowledgement protocol has been modified in this work to account for a burst control packet failure by implementing a traversal acknowledgement to cater for its loss. The performance of the distributed ant-based algorithm has been extensively evaluated on several network topologies and compared with that obtained by shortest path routing and ant colony routing and wavelength assignment. The results show that the distributed ant-based algorithm significantly improves the burst transmission success probability in the wavelength division multiplexed network environment and provides a good solution in the flexible spectrum network environment undergoing transmission impairments.     

Routing and Wavelength Assignment in Multi-Segment WDM Optical Networks using Clustering Techniques

This paper studies the routing and wavelength assignment (RWA) problem in multi-segment optical networks. The notion of network segment is referred to any part of the network that requires special consideration of wavelength routing such as separate administrative domains in a large scale optical network, sub-networks run by various service providers, etc. In multi-segment optical networks, each segment has different resource availability or hardware characteristics. The differences between multi-segment optical networks and homogeneous optical networks are discussed. We then present a resource abstraction technique called blocking island and define a multi-segment blocking island graph (BIG) network model. Using a minimum splitting routing heuristic introduced in the context of the blocking island paradigm in conjunction with the multi-segment BIG model, we propose a general RWA algorithm that takes a combined view of the network resource to integrate routing, wavelength assignment and gateway selection in a single routing framework. In the simulation, we demonstrate the effectiveness of our proposed algorithm by comparing it with other state-of-the-art heuristics in this area.     

Optically transparent integrated metro-access network

High-capacity optical transmission technologies have made possible very high data rates and a large number of wavelength channels. Further, optical network functionality has made progress from simple point-to-point WDM links to automatically switched optical networks. In the future, dynamic burst-switched and packet-switched photonic networks may be expected. This paper describes a novel architecture of transparent WDM metropolitan area network (MAN) that is capable of switching on both packet-by-packet and burst-by-burst basis, thereby having the potential to achieve high throughput efficiency. The optically transparent MAN also includes a large part of the access network infrastructure. It is scalable, flexible, easy upgradeable and able to support heterogeneous network traffic. Some results of a preliminarly study on network performance are shown.