SDH/SONET CES over Ethernet技术

本文简要介绍了SDH/SONET over Ethernet技术的优势和SDH/SONET CES仿真原理,重点介绍了SDH/SONETCES over Ethernet面临的技术挑战、分组包结构及系统时钟提取和同步.     

POS技术及发展趋势

本文介绍了通过ＳＤＨ直接传送ＩＰ分组的方法－ＰＯＳ。文章详述了ＰＯＳ所涉及的两个主要问题：协议数据的封装,高速路由器的实现。文章还针对其它ＩＰ五ＡＴＭ结合的方案,给出了ＰＯＳ技术几个突出的优点,即高效率,可扩展性和简单可靠,并结合数据运营商的实际,描绘了ＰＯＳ技术的应用前景。     

弹性分组环与SONET/SDH融合技术的研究

目前,IEEE802.17工作组正在进行弹性分组环(Resilient Packet Ring,RPR)的标准化工作,初步定义了弹性分组环的特性、功能,最后的标准将是一个MAC层协议并且独立于物理层。结合当前城城传输网中广泛应用的SONET/SDH技术,分析了弹性分组环和SONET/SDH平滑融合的实现方案,对于指导弹性分组环WAC层、融合子层(Reconciliation Sublayer,RS)设计以及实现弹性分组环组网具有重要意义。     

在SONET／SDH架构上实现以太网透明传输

技术与经济领域永远是充满理性的战场.过去几年在密集波分复用(DWDM)、10G SONET/SDH等技术上的突破,使得通信市场的竞争主要专注于长途干线领域,高速、宽带成了唯一的要素.喧嚣过去,加之全球经济遭遇挫折,使人们开始更多思考较为现实的问题,城域网由此成为新的竞争焦点.     

基于SDH/SONET的IP数据传送技术分析

SDH/SONET是目前最主要的传输技术,网络应用则以IP业务为中心,IP在SDH/SONET上的传送是一个重要问题.本文讨论IP在SDH/SONET上传送的传统PoA和PoS技术的基础上,详细分析了两种新的协议--简单数据链路(SDL,Simple Data Link)协议和通用成帧规程(GFP,Generic Framing Procedure),研究了各种协议技术的优缺点.     

SONET/SDH的软着陆

业务提供商和运营商们正在寻求一种方案,帮助他们从现有的静态ＴＤＭ复用时代过渡到动态ＩＰ业务网时代。 人们对接入网的要求正经历着戏剧性的变化。导致这种变化的主要因素有两个：第一、终端用户要求更多的廉价带宽、更多的控制能力与灵活性;第二、许多骨干网提供商正在建设具有难以置信的容量的长途网络。这种潮流加速了传输带宽价格的降低,其结果是对终端用户的带宽需求又起到了推波助澜的作用,为了满足这些新的需求,运营商和业务提供商对系统生产商提出了３个“简单”的要求： ＊帮助运营商和业务提供商大规模地扩展自己的网络以…     

Initial implementations of point-to-point Ethernet over SONET/SDH transport

There is considerable interest in using Ethernet over SONET/SDH (EoS) for Ethernet transport in a wide area network. EoS leverages the existing SONET/SDH infrastructure to provide efficient Ethernet transport with excellent OAM capabilities. In our initial evaluations and deployments of EoS, we have encountered some issues, as is common with any new technology. These issues include non-transparent transport of Ethernet information, lack of carrier-class performance monitoring and fault propagation, and non-standardized implementation of basic concepts. Vendors, service providers, and standards bodies should work together to resolve these remaining issues and thus bring forth the full potential of EoS.     

新一代SDH/SONET技术

从SDH/SONET光传输网的现状出发,分别对SDH/SONET ADMs的发展趋势、Data over SDH、RPR over SDH及GMPLS-SDH技术等作了介绍。     

提高SDH/SONET网络数据传输效率的解决方案

传统的SDH/SONET网络使用相邻级联,相邻级联使得高速网络互联成为可能。但是,随着数据传输的出现,这种级联方式的低效和不灵活性日益明显。本文讨论了这些缺点,并详细介绍了两个相对较新的处理这些问题的技术——虚级联和LCAS协议,列举了这些技术潜在的应用前景,最后给出了这些技术在EOS芯片中的实际应用结果。     

为适应未来而设计的SONET/SDH

在最初部署语音通信时,SONET/SDH就已在当今服务供应商网络的部署中发挥了重要作用,它将语音、视频及数据在强大可靠的单个传输机制上进行了完美组合。然而,当今部署的众多设备架构均无法充分进行扩展来满足未来不断增长的数据需求。此外,随着网络节点数量不断呈指数增长,配置并管理这些网络正变得日趋复杂。在当今注重低成本的服务供应商环境中,电信运营商正在寻求削减资金及运营支出的方法。他们需要对其现有SONET/SDH基础设施进行无缝扩展,以便不断提高容量,同时还能轻松提供并维持各种业务。     

Survivable virtual concatenation for data over SONET/SDH in optical transport networks

Next-generation SONET/SDH technologies-namely, generic framing procedure, virtual concatenation, and link-capacity-adjustment scheme-enable network operators to provide integrated data and voice services over their legacy SONET/SDH infrastructure to generate new revenue. An important open research problem on data over SONET/SDH (DoS) is survivability: SONET automatic protection switching is too resource inefficient for data services, and the protection mechanisms of data networks are too slow for mission-critical applications. We propose two approaches for provisioning survivable DoS connections. Our approaches exploit the tradeoff between resource overbuild and fault-recovery time while utilizing the inverse-multiplexing capability of virtual concatenation to increase backup sharing. Our results show that one approach achieves low resource overbuild and much faster fault recovery than that of data networks, and the other approach achieves fast fault recovery comparable to SONET 50-ms protection (for typical U.S. backbone networks) while still achieving modest backup sharing. We further investigate the tradeoff between network blocking performance and network control and management complexity resulting from the number of paths M a connection can be inversely multiplexed onto: larger M leads to more freedom in routing and better network performance but increases network control and management complexity. Our results indicate that the network blocking performance for small values of M (e.g., M=2 for some representative backbone network topologies) is almost as good as the case in which M is infinity.     

SDH/SON ET互通解决方案

本文从国际传送网建设的必要性、SDH/SONET的区别及其转换方案等进行论述,并以实际应用案例加以说明。     

Network synchronization-a challenge for SDH/SONET?

The basic characteristics and requirements of existing networks are summarized, focusing on network synchronization aspects and related parameters. The SDH/SONET-specific pointer-based multiplexing technique is described. It is shown that the need to synchronize the SDH/SONET network elements is not an inherent characteristic of these synchronous networks but rather a result of the generally applied pointer processor implementation. The principles of an advanced pointer processor implementation that is fully compatible with the existing telecommunication environment are outlined. This pointer processor does not require synchronization and, additionally, provides timing transparency. Measurement results demonstrating the feasibility of this approach are presented     

高性能同步数字传输/光纤网络芯片组

文中介绍了一种2．5Gbps同步数字传输／光纤网络（SDH／SONET）芯片组。发送器由MAX3890（合路器、时钟发生器）和MAX3867（激光驱动器）组成,总随机抖动仅为3．4psRMS,MAX3890可提供2．5Gbps时钟给MAX3867的输入锁定,用于数据信号的再定时,使MAX3867成为仅有的系统性抖动源,典型的系统性抖动≤50psRMS。接收器由MAX3866（TIA）、MAX3875（时种及数据恢复）和MAX3885（分路器）组成,总随机抖动仅4．6psRMS系统性抖动约为20psRMS。该芯片组对于ITU／Bellcore关于2．5Gbps SDH/SONET抖动规范有显著的设计裕量。     

New transport services for next-generation SONET/SDH systems

SONET/SDH systems have been the preferred transport technology over fiber optics for almost two decades now. Carriers have developed extensive expertise in operating, managing, and developing business models for these systems. Manufacturers' technical expertise in such systems has increased to a deep understanding of what transport over fiber is about. In short, SONET/SDH can be called a mature transport technology. Out of this mature expertise, new techniques for bettering transport over fiber services have appeared. These techniques are likely to considerably reshape the next generation of SONET/SDH systems in many aspects: new transport techniques, new transport services, new management systems and business models. We describe several new transport techniques, and discuss their impact on the creation of new transport services for next-generation SONET/SDH systems     

SDH/SONET虚拟级联技术

文章重点介绍了VC-4虚拟级联技术,对虚拟级联与相邻联这两种级联技术进行了比较。最后,就虚拟级联技术在SDH/SONET中的应用作了列表说明。     

SDH与SONET的异同

ＳＤＨ和ＳＯＮＥＴ是同步传输体制的两种标准，电信部门在设备引入时应注意这两种标准的异同；提供国际业务的公司还可能遇到这两种标准的系统互通问题，为此本刊特邀光纤传输领域的专家邬贺铨先生撰文，从系统速率，复用结构，净荷类型，通道指针，段开锁字节，能通道开销字节，维护告警判据，时钟性能等方面对ＳＤＨ与ＳＯＮＥＴ进行了比较，指出出了它们的不同之处，最后说明了ＳＤＨ与ＳＯＮＥＴ互通需注意的问题。     

Implications of SONET and SDH

The synchronous digital hierarchy (SDH) arose from a need for a new and single world multiplexing standard which could support switched broadband telecommunication services and for a standard optical interface for use by interexchange carriers. This tutorial paper reviews the features of SDH and outlines its frame structure. Network design and applications are reviewed and the paper concludes with a summary of the advantages of SDH     

PDH,SDH／SONET技术及其应用（一）

本文论述了ＳＤＨ／ＳＯＮＥＴ技术产生和发展及应用，并从理论上对ＰＤＨＴ和ＳＤＨ／ＳＯＮＥＴ作了技术比较，此外，还介绍了ＳＤＨ传输网络结构和ＳＤＨ传送设备。