光分组交换在下一代电力通信网中的应用

光分组交换是实现光传送网与电层IP网络无缝联接的理想技术.文章以电力通信网络为研究对象,对光分组交换技术在下一代电力通信网络中的应用进行深入探讨.首先,对光分组交换技术进行介绍,并分析了电力通信网的业务特性;然后,介绍了四种适用于电力通信网的光分组交换节点结构,即SMOP交换结构、FWBFWC交换结构、OFBFWC交换结构和RFWC-ROB交换结构.     

光分组交换网的TCP性能研究

与传统光网络相比,光分组交换(OPS)网络具有高速、大吞吐量、低时延和能高效地承载IP业务等突出优点.而作为支撑下一代Internet发展的最有希望的骨干光网络,OPS网与传输控制协议/互联网协议(TCP/IP)的兼容性和支持度是一个值得深入研究的课题.文章以光突发交换(OBS)网为模型,对OPS网络中的TCP传输性能进行了研究.     

全业务交换光分组传送体系架构研究

从网络平滑演进的角度看,基于分组传送同时兼容现有TDM传送技术的"全业务交换传送"的体系架构是实现光传送网向分组化方向演进的必然选择,也是电信运营商关心的主要问题之一.文章主要讨论了基于分组传送的全业务交换传送的体系结构及其实现方案,该体系结构的关键是在电层引入基于分组的T-MPLS交换技术,解决光传送网对分组业务的承载问题.该体系架构能够满足各种网络业务的传送需求,融合了数据、电路和光层传送功能于一体,支持数据/TDM/波长等不同技术信号的交换.     

光域上的几种交换技术

随着电传送网技术向光传送网技术的演进,光层联网能力愈来愈强,出现了几种粒度的光交换技术:线路交换(OCS)、光分组交换(OPS)、光突发交换(OBS)。本文将对这几种交换技术作一个说明,在此基础上介绍一种新颖的光交换技术:基于光分组流路由的光分组流交换(OFS)。     

面向IP的分组传送网发展思路

业务IP化触发了新一代光传送网——分组传送网的兴起,业务IP化对光传送网提出了更大带宽传送、更加灵活组网等新挑战。实现IP与传送融合的分组传送网定位于满足IP业务的高效传送、灵活组网、高可扩展性和高可靠性等方面。分组传送概念在不同发展阶段和不同网络层次所表现的形式不尽相同,在骨干网主要表现为IP over波分复用（WDM）／光传送网（OTN）／可重构光分插复用（ROADM）的大带宽传送,而在城域网范围主要表现为以传送多协议标签交换（T—MPLS）和电信级以太网（CE）为代表的分组交换和传送技术。     

基于OPS技术的超高速光孤子通信实现方案

通过对光分组交换(OPS)技术的讨论,实现了多交换节点的超高速光孤子通信传输方案.在详细阐述光孤子通信系统中光分组形式和OPS节点结构的基础上,进一步分析了传输方案实现的可行性,最后对该技术的优劣进行分析.指出,基于OPS技术的光孤子通信是实现未来全光网的首选.     

T-MPLS分组传送网分层体系结构的研究

文章首先针对传送业务从基于电路的时分复用(TDM) 业务向基于分组的业务转变对分组传送网的要求,说明了满足这一要求的分组传送网的总体分层结构,然后在此基础上给出了传送多协议标签交换(T-MPLS)分组传送网的分层结构,最后,分析了基于该结构的TDM和IP等业务的综合承载机制.     

电信网的演进趋势和发展展望(上)

本文从网络业务应用和网络交换技术两方面讨论了向IP化和分组化的汇聚和演进,向分组化演进的路线,基础传送网的宽带化,MPLS技术的发展,核心网向光联网的发展,业务层核心网的宽带化,面临挑战的城域网,接入网的宽带化和IP化以及网络功能结构的扁平化趋势。     

对于OTN与PTN联合组网技术分析

随着网络通信技术的不断发展,光传输网在接入层、汇聚层、核心层的发展渐渐转变为PTN(分组传送网)与OTN(光传送网)技术。采用分组传送网与光传送网完成网络部署,具备很多优越性。若业务疏导容量较大,则可使用光传送网技术,如果需要精细化管理客户与业务,便能够使用PTN技术。分组传送网的主要特征为分组交换内核,它可将SDH技术取代,对WDM技术中存在的不足进行弥补,促使网络传送能力与光缆资源利用率大大提升,使网络通信变得全光化、IP化与智能化。文章主要分析OTN与PTN联合组网技术,并对其特点进行研究。     

电信网的演进趋势和发展展望（上）

本从网络业务应用和网络交换技术两方面讨论了向IP化和分组化的汇聚和演进,向分组化演进的路线,基础传送网的宽带化,MPLS技术的发展,核心网向光联网的发展,业务层核网的宽带化,面临挑战的城域网,接入网的宽带化和IP化以及网络功能结构的扁平化趋势。     

Optical services in future broadband networks

Optical transmission technology is progressing to the point where it can deliver data at rates that can strain conventional electronic broadband networks. We discuss how optical networks may play a role in relieving this strain. Different optical network architectures are discussed according to the services they provide, the technologies used to implement those services, and the geographical size of the network. We first discuss broadband network architectures and where optics might play a role in the protocol stack. We then discuss in detail the services optical networks can provide, the technologies used to implement those services, and some of the major technological limitations. Finally, we use this knowledge base to analyze the potential role of optics in WANs, MANs, and then local area networks (LANs)     

Next-generation optical networks as a value creation platform

In this article we discuss the role of the next-generation optical networks and introduce enabling technologies that support network evolution. The role of networks is undergoing change and is becoming a platform for value creation. In addition to providing new services, networks have to accommodate steady traffic growth and guarantee profitability. We envision a next-generation optical network as the combination of an all-optical core and an adaptive shell operated by intelligent control and management software suites. Possible technological innovations are introduced in devices, transmission technologies, nodes, and networking software, which will contribute to attain a flexible and cost-effective next-generation optical network. New values will be created by the new services provided through these networks, which will change the ways we do businesses and go about our private lives.     

Dense wavelength division multiplexing networks: principles andapplications

The very broad bandwidth of low-loss optical transmission in a single-mode fiber and the recent improvements in single-frequency tunable lasers have stimulated significant advances in dense wavelength division multiplexed optical networks. This technology, including wavelength-sensitive optical switching and routing elements and passive optical elements, has made it possible to consider the use of wavelength as another dimension, in addition to time and space, in network and switch design. The independence of optical signals at different wavelengths makes this a natural choice for multiple-access networks, for applications which benefit from shared transmission media, and for networks in which very large throughputs are required. Recent progress in multiwavelength networks are reviewed, some of the limitations which affect the performance of such networks are discussed, and examples of several network and switch proposals based on these ideas are presented. Discussed also are critical technologies that are essential to progress in this field     

IP over WDM光网分层体系结构

介绍了传统的 IP over WDM光网实现方案 ,指出各种方案的优缺点。阐述了 IP directly overWDM光网的分层结构实现方案 ,分析了各层功能 ,详细讨论了光层和光适配层。在指出分层结构实现方案的利弊后 ,讨论了波长标记和多协议波长交换方案。     

Optical crossconnects of reduced complexity for WDM networks withbidirectional symmetry

One promising approach to provisioning and restoration in long-haul wavelength-division-multiplexing (WDM) networks is to deploy a mesh of optical crossconnects that operate on individual wavelengths. As wavelength-count and traffic demand rapidly increase, however, this approach will likely require high-port-count optical crossconnects that severely strain the capabilities of known device technologies. Thus, it is critical to devise ways to build large crossconnects from a small number of constituent switches, each with reduced port count. We present a general means of accomplishing this for networks, such as current long-haul networks, that demonstrate bidirectional symmetry. We describe a broad class of symmetry-exploiting architectures that yield N×N crossconnects, both rearrangeably nonblocking and strictly nonblocking, using constituent switch fabrics no larger than N/2×N/2. By exploiting connection-symmetry, these architectures reduce the number of such N/2×N/2 fabrics by 30%-50% compared with corresponding fully connected three-stage Benes and Clos switch structures     

Architectures and technologies for high-speed optical data networks

Current optical networks are migrating to wavelength division multiplexing (WDM)-based fiber transport between traditional electronic multiplexers/demultiplexers, routers, and switches. Passive optical add-drop WDM networks have emerged but an optical data network that makes full use of the technologies of dynamic optical routing and switching exists only in experimental test-beds. This paper discusses architecture and technology issues for the design of high performance optical data networks with two classes of technologies, WDM and time division multiplexing (TDM). The WDM network architecture presented stresses WDM aware Internet protocol (IP), taking full advantage of optical reconfiguration, optical protection and restoration, traffic grooming to minimize electronics costs, and optical flow-switching for large transactions. Special attention is paid to the access network where innovative approaches to architecture may have a significant cost benefit. In the more distant future, ultrahigh-speed optical TDM networks, operating at single stream data rates of 100 Gb/s, may offer unique advantages over WDM networks. These advantages may include the ability to provide integrated services to high-end users, multiple quality-of-service (QoS) levels, and truly flexible bandwidth-on-demand. The paper gives an overview of an ultrahigh-speed TDM network architecture and describes recent key technology developments such as high-speed sources, switches, buffers, and rate converters     

Proposal of networking by PON technologies for full and ethernet services in FTTx

The construction of optical access networks is one of key issues to provide new broad-band services and emulation of legacy services. Passive optical network (PON) technologies realize sophisticated and economical optical access networks for these purposes. This paper summarizes requirements and technical and marketing trends for optical access networks. It also presents advantages of networking by PON technologies for optical access networks. Moreover, it clarifies issues to install and operate PON base optical access networks and proposes solutions for these issues.     

An architectural framework for seamless handoff between IEEE 802.11 and UMTS networks

In recent years, Cellular wireless technologies like GPRS, UMTS, CDMA and Wireless Local Area Network (WLAN) technologies like IEEE 802.11 have seen a quantum leap in their growth. Cellular technologies can provide data services over a wide area, but with lower data rates. WLAN technologies offer higher data rates, but over smaller areas, popularly known as ‘Hot Spots’. The demand for an ubiquitous data service can be fulfilled, if it is possible for the end-user to seamlessly roam between these heterogeneous technologies. In this paper, a novel framework is proposed consisting of intra-ISP network called ‘Intermediate Switching Network’(ISN) fused between UMTS and WLAN networks as well as data (Internet) services for providing seamless mobility without affecting user’s activities. The ISN uses MPLS and Multiprotocol-BGP to switch the data traffic between UMTS to IEEE 802.11 networks, as per the movements of the user. The ISN is integrated with the UMTS network at the GGSN-3G and at the Access Point for IEEE 802.11 network respectively. The simulation result shows the improved performance of the ISN based framework over existing schemes.     

Reconfigurable free-space optical cores for storage area networks

The role of the optical storage area network is becoming increasingly important in computer network architectures, with the amount of information being presented and requested on the Internet ever increasing. One of the key questions is what is the role of, and how do we control, an optical switch core within a SAN to optimize its performance. In this article we review two potential optical switch technologies and assess their performance as a SAN optical switch core.     

A broadband optoelectronic packet switching system

A novel architecture is presented for a optoelectronic hybrid packet-switching system (HYPASS) for the distribution of multiple-bit-rate broadband services. HYPASS is based on an input-buffered/output-controlled arbitration protocol. This packet switch uses novel multiwave-length optical networks to accomplish routing and transmission of the packets. This system is specifically adapted to utilize the strengths of both optical and electronic technologies