基于多物理层损伤限制的光网络RWA算法研究

在透明光网络中,如何在选路过程中自适应地规避物理层损伤进而实现高质量的传输服务是亟待解决的问题.提出了一种面向多物理损伤约束的RWA算法,改进原有损伤感知RWA算法考虑物理损伤单一不够全面的问题,尝试将多个物理损伤作为路径选择的多个约束条件,从而可以选择损伤最小的光路来完成光连接的请求,从而满足未来高传输质量的需求.     

电传送网向不传送网进化的过程

分两部分叙述了电传送网向光传送网进化的过程。第一部分叙述近年来以时分多路为基的电传送网的改进与发展,它采用同步数字体系,并在光纤传输线路上装用波分多路系统和光纤放大器。第二部分简单说明在不久的将来可能实用的、以波分多路为基础光传送网,其结构中的所有网络单元全是由光的代替电的。     

电传送网向光传送网进化的过程

分两部分叙述了电传送网向光传送网进化的过程.第一部分叙述近年来以时分多路为基的电传送网的改进与发展,它采用同步数字体系.并在光纤传输线路上装用波分多路系统和光纤放大器,第二部分简单说明在不久的将来可能实用的、以波分多路为基的光传送网,其结构中的所有网络单元全是由光的代替电的.     

A high-reliability optical network architecture based on wavelength division multiplexing passive optical network

A highly reliable wavelength division multiplexing passive optical network architecture for the fifth generation (5G) applications is designed by combining a tree topology with a dual-fiber ring. While the tree topology ensures the transmission quality of the network, the dual-fiber ring topology allows one to achieve flexible switching between the nodes, which aims to provide fault protection and network reliability. The signal transmission under the normal and three types of protection modes are analyzed. The performance analysis verifies the feasibility of the proposed architecture.     

WDM光网络中光层组播技术的研究

本文分析了光层组播原理。在物理层实现组播 ,使该技术在整个互联网实施实时交互音像通信和有效抑止“电子瓶颈”效应有着重大作用。文中对两种不同结构具有光层组播的OXC进行了分析比较。并且对WDM光网络中的无阻塞组播通信波长满足条件进行了分析探讨。     

基于SDN的光传送网研究

SDN作为目前通信行业热门技术,主要利用控制和数据相分离的思想,对网络和业务进行可编程,从而解决目前互联网技术的快速发展下带来的宽带需求量大、建设成本高、调度不灵活等问题,虽然SDN的网络演进还处于初级阶段,但SDN对整个光传送网带来的影响仍需要积极研究。     

基于开放光传送网络的域间故障定位技术研究与实践

目前,不同专业设备的网络管控系统相对独立,如何快速恢复域间光网络故障是当下网络运维需要解决的问题。针对域间光网络的故障定位方案展开研究,域间网络发生故障后,先通过链路自动发现协议和光模块调顶技术获取完整的链路信息和模块数据,再利用性能实时监控技术和根因分析功能找到当前故障的根告警。综合运用这些方法并通过开发的传输网络运行质量分析原型系统将光传送网络的管理域外延,从而形成包含远端客户侧在内的端到端的开放光传送综合管控系统。     

OTN和PTN的联合组网研究

在对光传送网(OTN)和分组传输网(PTN)进行分析的基础上,提出了OTN和PTN联合组网的问题,讨论了OTN和PTN的联合组网方案,着重研究了PTN业务在大带宽OTN通道中如何传送的问题,即PTN业务如何适配到OTN网络中。最后,对OTN和PTN联合组网的发展趋势进行了展望。     

面向TD-LTE的城域传送网核心层组网探讨

TD-LTE相比TD-SCDMA,对城域传送网提出了更高的要求。本文在分析了TD-LTE对城域传送网带宽需求和核心网设置方案的基础上,对城域传送网核心层不同场景下的组网方案进行了探讨,并给出合理化建议。     

光传送网的故障管理

用分层方法讨论了光传送网络的告警管理功能,着重分析了全光网络中缺陷指示信号的起源、传输与终结问题,此外还对光监控信道的故障情况的处理方法进行了讨论。     

光通信网开始实际运用

首选对光通信网的涵义作一概述,然后较明确地说明以波分复用为基础的光通信网的具体内容,最后,介绍欧洲近年开始筹建泛欧波分复用光通信网实际运用的情况。     

光传送网络成帧器设计

针对超高速率的光传送网络(Optical Transport Network,OTN)数据信号,在研究光传送网络帧结构的基础上,提出了一种适合高速率、大位宽的成帧器处理电路,将48比特的FAS信号分为两部分进行比较,第一部分为64个24比特比较器,第二部分为一个24比特比较器。将电路的规模降低了一半,提高了电路的处理速率。通过软件仿真后,使用综合工具综合的结果显示,电路处理速率可达到235.74MHz。     

光网逻辑层的生存性技术(本期优秀论文)

提出了生存性技术的基本分类原则和光网络生存性的分层视图,在此范畴内,分析比较了包括纯链路、纯路径、Meta-Mesh、p-cycles、SBPP、SLSP在内的逻辑层生存性技术,最后总结出逻辑层生存性技术所具有的灵活性和容量利用高效率的特征.     

传统的传送网向自动交换光网络的演进

叙述了准同步数字传送网向同步数字传送网，同步数字传送网向波分复用(WDM)XX传送网的演进过程。阐明了传统的传送网必然向自动交换光网络(ASON)演进的观点。着重介绍了ASON的体系结构、网络结构、功能特点、控制平面的功能构件、标准接口以及实现ASON控制平面的关键控制协议规范。     

A transport layer for live streaming in a content delivery network

Streaming media on the Internet has experienced rapid growth over the last few years and will continue to increase in importance as broadband technologies and authoring tools continue to improve. As the Internet becomes an increasingly popular alternative to traditional communications media, Internet streaming will become a significant component of many content providers' communications strategies. Internet streaming, however, poses significant challenges for content providers, since it has significant distribution problems. Scalability, quality, reliability, and cost are all issues that have to be addressed in a successful streaming media offering. Streaming content delivery networks (streaming CDNs) attempt to provide solutions to the bottlenecks encountered by streaming applications on the Internet. However, only a small number of them has been deployed, and little is known about the internal organization of these systems. In this paper, we discuss the design choices made during the evolution of Akamai's CDN for streaming media. In particular, we look at the design choices made to ensure the network's scalability, quality of delivered content, and reliability while keeping costs low. Performance studies conducted on the evolving system indicate that our design scores highly on all of the above categories.     

OTN中FEC技术的应用

光传送网(OTN)是随着WDM技术的发展而产生的,ITU—T在2001年提出了其接口标准——G．709建议。该建议采用数字包封技术,定义了数据的封装格式,将前向纠错(FEC)技术引入光传送网标准接口中。文章分析了OTN的帧格式,着重介绍了其采用的FEC技术。将G.709标准应用到实际光接口盘的设计中,并通过实验验证了FEC技术的良好效果。     

A simple high-speed optical local area network based on flooding

The problem of interconnecting many high-speed terminal users via an optical local area network (LAN) is addressed. Space-division multiplexing (SDM) is used to provide point-to-point connectivity, so simple light sources and receivers are all that is required. The call setup between a source and a destination is based on the broadcasting of a short address packet called flooding, which is a simple topology-independent routing method that alleviates the need to have intelligent nodes (cross points). A simple protocol is used to establish an end-to-end path using flooding. Once a source/destination path is established, the actual call starts. The established path is not interrupted by other call setup flooding attempts and/or other cells. A performance analysis for a simple tree network indicates that a capacity of 66% can be achieved at reasonable average blocking delays. The network users can each access full electronics speeds, and the total throughput of the network is a multiple of full electronics speed, with concurrency achieved by SDM     

Photonic transport networks based on optical paths

This paper explores the technologies that will enable a further leap forward in transport network evolution. First, requirements of the future transport network are elucidated. Existing network cost is evaluated and the viable means to reduce transport network cost are identified. It is demonstrated that optical path technologies such as WP (wavelength path) and VWP (virtual wavelength path) will play a key role in this. They enhance not only transmission capacity but also cross-connect node throughput cost-effectively by capitalizing on the wavelength routeing scheme. Optical path realization technologies focusing on optical path cross-connect systems are examined. Requirements for the optical path cross-connect system are then elucidated, and a new cross-connect system architecture is evaluated. The architecture exploits PLC (planar lightwave circuit) and other commercially available technologies suitable for large-scale production. The evaluations include cross-connect node upgradability, modular growth capability, total node cost, optical loss and switching power consumption. It is proved that the architecture has significant advantages over existing switch architectures. The optical path technologies provided in this paper will pave the way for a new transport network paradigm, a ubiquitous, bandwidth-abundant and affordable broadband ISDN.     

基于强化学习的光传送网路由波长优化

针对光传送网中动态业务的路由和波长问题,提出一种基于强化学习的深度路由波长分配算法DeepRWA。算法基于软件定义网络架构,通过强化学习灵活地调整控制光传送网,实现光网络路由波长分配策略优化。针对路由选择问题,结合链路上的波长使用情况,使用A3C算法选择合适的路由,使得阻塞率最小;针对波长分配问题,使用首次命中算法选择波长。考虑阻塞率、资源利用率、策略熵、价值损失、运行时间及收敛速度等多个指标,利用14节点NSFNET网络拓扑仿真实验。结果表明:当信道中包含18个波长时,与传统KSP-FF算法相比,所提出的路由波长分配算法的阻塞率降低了0.06,资源利用率提高了0.02,但运行时间有增加;在波长数超过45以后,与传统KSP-FF算法相比,所提算法保持阻塞率和资源利用率的同时,运行时间开始降低;当信道中包含波长数为58时,与传统KSP-FF算法相比,所提算法运行时间减少了0.07 ms。由此可见,提出的算法使路由选择和波长分配得到了优化。