光交叉连接器的光传输中的应用

目前以IP业务为代表的数据业务爆炸式增长,单信道传送速率从2.5Gb/s到10Gb/s到40Gb/s的快速增长,密集波分复用技术的使用,骨干网的电信级大容量快速交换需求,使得对光传送网交换节点的要求越来越高.网络的生存性、网络的恢复和自愈问题都变得非常重要.光交叉连接器(OXC)技术的发展,替代了复杂昂贵的电交叉连接,使空闲光纤数减少.同时,不需要光电转换,提供了比电交叉连接更高的交换效率.OXC能在光层解决网络恢复和自愈问题,极大地提高了网络的生存性和恢复速度.因此,光交叉连接器作为光传送网的关键设备,它的发展将对光传送网起到重大的推动作用.     

光传送网引入SDN的方案研究

近年来传送网技术发展迅速,分组传送网(PTN)技术、光传送网技术(OTN)相继部署,传送网从原来单一技术的网络发展到目前多种技术网络的融合组网,并且随着网络规模也不断扩大,网络变得越来越复杂.如此大规模的网络其管理和互操作性成为光网络发展的一大难题,不同厂家设备网络、不同域之间电路调度变得十分复杂且代价昂贵.SDN技术为解决该问题提供了很好的途经,本文就目前软件定义光传送网(T-SDN)技术相关标准化进程进行梳理,并对光传送网引入SDN的方案进行研究.     

光传送网络可靠性与安全性分析

文章概述了光传送网络技术的发展趋势,分析了影响光传送网可靠性和安全性的主要因素,并从传输设备到整个网络系统,运用层层推理的方法,基于常见的网络模型详细描述了传送网络可用率的计算过程。文章还就如何增强光传送网可靠性和安全性,描述了运用保护和恢复这两种机制在提高传送网可靠性中的重要意义。最后总结了不同因素对传送网可用性影响的敏感性,从而概括了传送网上实现差异化服务的思路。     

WDM光传送网生存性以及多层网络恢复策略

网络的生存性一直是传送网研究的重点。对于 WDM光传送网 ,可以在光层进行业务恢复 ,提高了网络抗故障能力。分析了光层恢复的特点和所存在的问题 ,以及多层网络恢复方案相互协调的策略     

面向未来的光传送网（OTN）技术

阐述了光传送网的特征、功能和分层、连接、生存技术、网络管理和连接监视技术，并对实现光传送网的关键技术进行了简要的介绍。     

面向未来的光传送网（OTN）技术

阐述了光传送网的特征、功能和分层、连接、生存技术、网络管理和连接监视技术，并对实现光传送网的关键技术进行了简要的介绍。     

光传送网弱光的影响因素和优化方法分析

针对光传送网（OTN）弱光严重影响家集客业务用户感知的现状背景，从网络规划、配套环境、装维工艺和构件质量4个方面分析光传送网弱光的主要影响因素，从加强网络规划的执行效果、提升配套环境的总体质量、强化装维工艺的现场监督和提高构件质量的采购标准4个方面解析光传送网弱光优化的主要方法，从降低光分配网络路由长度和减少光分配网络转换数量两个方面探索光传送网弱光的未来优化技术。研究结果表明光传送网弱光改善对家集客业务质量提升具有重要作用，通过近期和远期两个层面的技术优化，有助于实现光传送网网络质量提升，对家集客业务发展具有推动作用。     

光交叉连接器在光传输中的应用

目前以IP业务为代表的数据业务爆炸式增长,单信道传送速率从2.5Gb/s到10Gb/s到40Gb/s的快速增长,密集波分复用技术的使用,骨干网的电信级大容量快速交换需求,使得对光传送网交换节点的要求越来越高。网络的生存性、网络的恢复和自愈问题都变得非常重要。光交叉连接器（OXC）技术的发展,替代了复杂昂贵的电交叉连接,使空闲光纤数减少。同时,不需要光电转换,提供了比电交叉连接更高的交换效率。OXC能在光层解决网络恢复和自愈问题,极大地提高了网络的生存性和恢复速度。因此,光交叉连接器作为光传送网的关键设备,它的发展将对…     

电信辞库

光交叉连接设备光交叉连接（OXC,OpticalCross－Connect）设备是光传送网中最重要的网元设备之一,是电的交叉连接器在光域内的实现。其主要实现光域内的交叉连接和本地上下路功能,为不同的光通道业务进行路由选择和波长指配,对汇接业务进行管理,对光传送网进行动态配置。OXC主要应用于格形骨干网、城域网和骨干网与城域网汇接处。通过波长路由优化算法（RWS）,OXC可以动态重构网络。当网络发生故障时,OXC可以为故障段的光通道重选路由,实现网络的自动恢复,从而提高了网络的生存性。OXC的交换核心可以在电域或光域完成。电…     

光网络的发展与展望

首先简要介绍了光网络的基本概念,然后阐述了光传送网的主要优势,接下来分别论述了IP业务量对传送网结构的影响、从点到点WDM向光联网演进的必要性和演进的步骤以及全光光交叉连接设备的现状与发展,最后阐述了光传送网络向ASON演进的必然趋势.     

Connection provisioning with guaranteed recovery time in survivable WDM optical networks

Optical networks employing wavelength- division multiplexing (WDM) are prone to failures. In case of a failure, the time to recovery is an important metric, since the amount of lost information and the performance of carried application strongly depends on the time of service interruption. Moreover, as the current trend in network development is moving toward a unified solution providing support for voice, data and various multimedia services, different application and users may tolerate different time of service interruption. Therefore, it is imperative to provide recovery-time guaranteed connections in WDM optical networks. In this paper, we propose a new shared-segment protection algorithm, called AGBSP-QoP, to provision connection requests according to their differentiated recovery-time requirements. Given a working path, AGBSP-QoP first computes all possible recovery-time guaranteed working-backup segment pairs, and then dynamically selects a least-cost eligible subset based on a dexterously constructed auxiliary graph. We conduct simulations under single class of service and multiple classes of service, and compare AGBSP-QoP with other protection algorithms. The results show that AGBSP-QoP yields the best performance and can properly provision connection requests according to their differentiated recovery-time requirements.     

Link-State-Based Algorithms for Dynamic Routing in All-Optical Networks with Ring Topologies

The increased usage of large bandwidth in optical networks raises the problems of efficient routing to allow these networks to deliver fast data transmission with low blocking probabilities. Due to limited optical buffering in optical switches and constraints of high switching speeds, data transmitted over optical networks must be routed without waiting queues along a path from source to destination. Moreover, in optical networks deprived of wavelength converters, it is necessary for each established path to transfer data from source to destination by using only one wavelength. To solve this NP-hard problem, many algorithms have been proposed for dynamic optical routing like Fixed-Paths Least Congested (FPLC) routing or Least Loaded Path Routing (LLR). This paper proposes two heuristic algorithms based on former algorithms to improve network throughput and reduce blocking probabilities of data transmitted in all-optical networks with regard to connection costs. We also introduce new criteria to estimate network congestion and choose better routing paths. Experimental results in ring networks show that both new algorithms achieve promising performance.     

A Pre-Planned Local Repair Restoration Strategy for Failure Handling in Optical Transport Networks

Automatic provisioning and recovery of lightpaths with selectable traffic engineering policies are considered basic features of near future optical transport networks (OTN). Worldwide researchers recognize generalized multi-protocol label switching (GMPLS) architecture as the viable control plane solution to achieve these issues in OTN. Growing effort is ongoing to find new recovery models for handling failure conditions in the networks, trying to set up alternative strategies to classical heavy-cost SDH/SONET protection techniques. In this paper, a pre-planned local repair recovery strategy is described. Allocation of primary paths is provided using the interference concept, in order to set a threshold between resources dedicated to working paths and those allocable for local backups in case of failure. Tests of the strategy are shown for a sample national optical transport network, aimed at valuing local-repair recovery times at different failure location and seriousness.     

Minimum connection count wavelength assignment strategy for WDM optical networks

In this paper, we have proposed one wavelength assignment strategy for optical networks which assigns the wavelength according to minimum connection count. The performance of proposed strategy is compared with the most commonly used strategy among the existing strategies in terms of number of searches to find the wavelength for connection establishment. The searching takes the time and directly affects the connection establishment time. The simulation is done using different network models. The results show that the proposed strategy is much better than existing strategy in terms of number of searches required to find a wavelength for establishing the connection and hence connection establishment time reduces.     

基于地址差额标记的光网络差别服务质量保证

提出了一种适用于哈密顿环保护(HCP)的地址差额标记(ADL)的光节点结构,并在此节点结构基础上实现了差别服务质量(QoS)的光网络保护策略。采用ADL光节点,保护机制可以在光层中直接完成,不需要光电转换。同时可实现对不同业务的QoS保证,进一步减少了对于备用保护波长的要求。分析了ADL光节点下的HCP网络阻塞情况,讨论了不同保护资源下的网络路由阻塞率Blocking—R和预保护资源不足造成的阻塞率Blocking—P以及它们之间的相互关联,并提出当Wp／W=1时基于ADL的HCP网络才能获得有效的服务质量保证。     

Effects of Optical Buffering on the Performance of Manhattan Street Networks

Multihop networks are strong candidates for the implementation of high-speed networks, ranging from back-plane networks for cluster computing to metropolitan-area networks. Besides using deflection routing for contention resolution, optical buffering may be used to enhance the performance of optical multihop networks and to reduce or even eliminate the need for optical-electrical conversions. The enhancements obtained by augmenting traditional MSN (Manhattan Street Networks) with optical buffering are evaluated. The MSN considered here is based on a novel 6 × 6 optical switching node with up to two fiber delay loops. Impact of the parameters associated with optical buttering, such as the number of delay loops and the loop length, are discussed in detail.     

CLEP——一种新的全光网络光路建立协议

本文提出了一种波长交换光网络中混合模式的光路建立协议CLEP,该协议充分利用现有基于正向预留的CR-LDP协议和基于反向预留的RSVP-TE协议各自的特点,通过使用混合模式的光路建立机制,使得信令协议在控制消息负载、实现复杂度、连接阻塞概率和连接建立时间等方面具有更好的性能.     

Enhanced Dynamic Segment Protection in WDM Optical Networks under Reliability Constraints

In this letter, we study the protection problem in wavelength division multiplexing (WDM) optical networks, and propose a novel dynamic heuristic algorithm called differentiated reliable segment protection (DRSP). Differing from previous work, DRSP can effectively avoid the trap problem and is able to find a feasible solution for each connection request. Therefore, DRSP outperforms the previous work. Simulation results have shown to be promising.     

Optical multicast over wavelength-routed WDM networks: A survey

With the rapid development of optical networking technology, it is now a realizable technique to support point-to-multipoint connections directly on the optical layer, giving rise to optical multicast. The topic of optical multicast has attracted much enthusiasm in recent years for the reason that it will not only make full use of the abundant bandwidth provided by optical fibers, but also take full advantage of multicast over the traditional point-to-point connection approach. In this paper, we present a comprehensive review of optical multicast over wavelength-routed WDM networks, covering the development of both data plane and control plane designs. In particular, we provide an up-to-date state-of-the-art review on the multicast routing and wavelength assignment problem. To the best of our knowledge, this is the most thorough and comprehensive review conducted so far on this topic in the literature.     

Connection Establishment of Label Switched Paths in IP/MPLS over Optical Networks

We propose and investigate three connection admission control policies for the establishment of label switched paths (LSPs) in IP/MPLS over optical networks. We show that the policy of establishing LSPs first in the optical layer achieves a better blocking performance. We examine the effect of the number of add/drop ports of optical cross-connects (OXCs) on the LSP blocking performance. We show that there exists a lower bound for the number of add/drop ports of OXCs for the network to achieve almost the best LSP blocking performance.