参加ITU—TSG13研究组1997年2月会议总结报告（下）

２－４ＳＤＨ和光传输网２－４－２虚级联ＡＴＭ能提供带宽利用的灵活性，但目前的ＡＴＭ系统还不能实现在故障情况下对ＶＰ（虚通道）或ＶＣ（虚通路）的快速恢复。ＳＤＨ系统虽能提供对ＭＳ（复用段）或ＶＣＰａｔｈ（虚容器通道）的快速恢复，但对映射速率介于ＶＣ１２（ＶＣ１１）、ＶＣ２、ＶＣ３和ＶＣ４中间的业务信号缺乏带宽利用的有效性和灵活性，特别在接入网中，这个问题尤为突出。解决的办法对ＡＴＭ而言是开发自动保护倒换能力，对ＳＤＨ系统而言是提供级联能力，而且后者的技术解决也有利于支持ＡＴＭ反向复用器（ＩＭＡ）的…     

基于VP的ATM自愈网

介绍了ＡＴＭ自愈网的研究背景，对ＡＴＭ自愈网中采用的三种再选路由定位策略和两种再选路由计算方案分别进行了说明和讨论，最后把ＡＴＭ自愈网同ＳＤＨ自愈网作了全面比较。     

SDH在B—ISDN中的应用

在构建未来的宽带综合业务数字网中，ＳＤＨ和ＡＴＭ是两大关键技术，本文介绍了ＳＤＨ传送网的基本特点，ＡＴＭ的基本概念；指出ＳＤＨ是Ｂ－ＩＳＤＮ的传输主干网，讨论了ＳＤＨ和ＡＴＭ互通的必要性及其实现。     

基于VP的ATM自愈环

本文介绍了ＡＴＭ自愈环的结构及其自愈控制机理，对ＶＰ的建立和管理进行了说明和讨论，最后对ＡＴＭ自愈环和ＳＤＨ自愈环的性能及造价作了详细比较。     

有线电视网与宽带综合业务网

本文针对有线电视网的光缆改造，介绍和分析了ＨＦＣ、ＨＤＳＬ、ＡＤＳＬ以及ＳＤＨ、ＡＴＭ有关网络技术和特点，提出了有线电视ＨＦＣ的发展方向和采用ＡＴＭ交换技术实现ＨＦＣ高速宽带综合业务网的思想。     

SDH／ATM自愈网络的层间升级机制

在一个分层网络中,单一的恢复机制不可能满足宽带网络生存性的需要,如何协调配合ＳＤＨ层和ＡＴＭ层之间的恢复策略是一个亟待解决的问题。文章首先介绍了ＳＤＨ和ＡＴＭ网络的自愈技术,然后对ＳＤＨ／ＡＴＭ自愈网络的层间升级机制进行了讨论。     

光纤／同轴电缆混合网时隙同步进程的实现

光纤／同轴电缆混合网（ＨＦＣ）解决了Ｂ－ＩＳＤＮ和信息高速公路的用户接入瓶颈问题。本文概述了ＨＦＣ网络系统，给出了基于ＡＴＭ的ＨＦＣ网络的前端和基站的工作机理和结构框图，提出了一种实现基站接入过程中时隙同步进程的新方法。     

B—ISDN的展望

２１世纪ＩＳＤＮ业务定为视频化，灵活性和专用化方向的高性能化。支持网络是宽带ＩＳＤＮ（Ｂ－ＩＳＤＮ）。目前，ＣＣＩＴＴ中规定传送方式采用ＡＴＭ技术，Ｂ－ＩＳＤＮ的规范化还在急速地向前发展着，基本的具体化的向实用化探索，对以上所述方面还正在研制着。本文叙述了根据ＡＴＭ技术实现Ｂ－ＩＳＤＮ，归纳ＮＴＴ近年来的成果，俯瞰本刊的诸技术，作为未来网络的展望。     

功率控制对S-CDMA-HFC系统上行信道Erlang容量的影响

同步ＣＤＭＡ（Ｓ－ＣＤＭＡ）解决了双向ＨＦＣ系统的上行信道噪声和容量问题,基于Ｓ－ＣＤＭＡ的ＨＦＣ是新一代ＨＦＣ系统。从系统实现的角度来看,非理想功率控制会明显降低系统业务容量。本文简单介绍了Ｓ－ＣＤＭＡ－ＨＦＣ系统模型和上行信道概况,分析了非理想功率控制对Ｓ－ＣＤＭＡ－ＨＦＣ系统上行信道Ｅｒｌａｎｇ容量的影响,并给出了数值结果与结论。     

B—ISDN和ATM与宽带通信业务

本文首先通过对宽带业务发展情况，ＡＴＭ标准，ＡＴＭ适配层的分析引出了ＡＴＭ对Ｂ－ＩＳＤＮ发展的作用及向Ｂ－ＩＳＤＮ过渡的步骤，并指出工发具ＳＭＤＳ和ＦＲ业务接口的ＡＴＭ交换机，对实现Ｎ－ＩＳＤＮ向Ｂ－ＩＳＤＮ过渡具有积极现实意义，其次介绍和分析了ＩＴＵ－Ｔ，日本ＮＴＴ及欧洲各国关于ＡＴＭ和Ｂ－ＩＳＤＮ的标准化活动，应用试验等情况。     

A passive protected self-healing mesh network architecture andapplications

The self-healing mesh network architecture using digital cross-connect systems (DCSs) is a crucial part of an integrated network restoration system. The conventional DCS self-healing networks using logical channel protection may require a large amount of spare capacity for network components (such as DCSs) and may not restore services fast enough (e.g., within 2 s). The authors propose a passive protected DCS self-healing network (PPDSHN) architecture using a passive protection cross-connect network for network protection. For the PPDSHN architecture, network restoration is performed in the optical domain and is controlled by electronic working DCS systems. Some case studies have suggested that the proposed PPDSHN architecture may restore services within a two-second objective with less equipment cost than the conventional DCS self-healing network architecture in high-demand metropolitan areas for local exchange carrier networks. The proposed PPDSHN architecture may apply to not only the centralized and distributed control DCS network architectures, but also asynchronous, SONET and ATM DCS networks. Transparency of line rates and transmission formats makes the PPDSHN network even more attractive when network evolution is a key concern of network planning     

MSB虚通路自愈在ATM网络中的应用

针对已有的 ATM自愈方式 ,提出了基于多段备份虚通路概念的自愈方法。利用 P/ T方法着重对恢复概率进行了公式推导 ,最后仿真计算结果表明 ,该方法要比已有的方法可靠性高。     

ATM VPX网络中一种生存性策略

在未来ＡＴＭ网络中，网络生成能力是一个关键而亟待解决的问题，在链路或节点失效的情况下，ＡＴＭ网络应能将连接快速切换到变更路由上，最大限度减少由此造成的经济损失和负面社会影响，本论文研究ＡＴＭＶＰＸ（ＶＰ交叉连接）网络中的生存性策略，提出关键的两个算法；混合式自愈算法和空闲资源算法，同时提出了与其相关的基于ＶＰ的综合控制机制，该策略能快速地恢复受失效影响的连接，又能使网络资源得以合理利用。     

DCS网状网自愈的进展

数字交叉连接系统(DCS)网状网是电信传输骨干网的主要拓扑结构。本文讨论了DCS网状网自愈的进展,其中包括SDH、ATM和WDM网状网自愈,同时说明了它们之间的相互关系。对电信传输网自愈和电信业务网的关系也进行了讨论。     

SDH网状网自愈

 本文讨论了SDH网状网的自愈.由于交叉连接系统交叉连接时间的缓慢,SDH网状网不能在整体上达到2秒的恢复时限.优先级恢复保证对高优先级通道达到2秒的恢复时限.设想的恢复体系包括两个阶段:对高优先级通道的分布式虚倒换和对低优先级通道的分布式自愈;高优先级通道能在2秒或更短的时间内恢复,低优先级通道的恢复需要数秒.为了实现上述恢复体系,提出了一种多路由带宽分配方法和一种消息传播机制,这两种方法在网络正常时使用.     

Warren: a low-cost ATM home area network

This article introduces the concept of the ATM Warren. The Warren is an arbitrary mesh subnetwork of very simple ATM switches and end stations connected to the wide-area B-ISDN at one or more points. The Warren differs from other ATM networks in that both switches and end stations are designed to be implemented entirely in hardware with all control software banished to external computers     

Granulated broadband network applicable to B-ISDN and PSTN services

A granulated broadband network (GBN) is proposed as an intermediate asynchronous transfer mode (ATM) based platform to be part of an evolution scenario toward B-ISDN. The GBN enables various types of services to be provided including 64-kb/s-based services and broadband services. In the GBN, information is transformed into ATM cells at subscriber line terminals or at customer premises and is transferred through ATM networks; consequently, the cost feasibility of a single-channel cell assembly/deassembly device is a significant factor in economically providing ATM-based conventional services and interworking between STM and ATM networks. Various virtual path capacities with a fine degree of granularity can be provided in a mesh structure between transit modes in the GBN. Economic feasibility studies of the GBN, by simulating on certain large-size real networks in the greater Tokyo area, indicate the possibility of a more than 50% cost reduction in transit networks     

VP带宽规模对ATM自愈网的影响分析

网络环境对自愈性能的影响是十分重要的。本文分析了ＡＴＭ自愈网中ＶＰ带宽规模对自愈性能的影响以及对网处理负担、ＶＰＩ资源的影响。只要适当选取ＶＰ带宽规模，ＶＰ层和ＶＣ层的恢复率将尽可能高，同时ＶＰＩ资源消耗、网处理负担以及恢复时间、恢复消息数目都有所增加，但若采用高速ＤＣＳ和高效自愈算法，恢复时间和恢复消息数的增加都可以受到限制。     

光通信中基于DCS的分布式自愈功能

随光纤传输系统向大容量，调整率发展，自愈在网络发生故障时占有越来越重要的地位。本文提出了一种用于ＤＣＳ网状网的基于链路恢复的分布式动态路由自愈率算，并对该算法进行了计算机模拟，分析了该算法比其他算法的优越性。     

Service applications for SONET DCS distributed restoration

This paper determines the scope of network applications and services that could be offered using a SONET DCS-based self-recovering mesh architecture with distributed control. The study includes an outage impact analysis on network services and a determination of how network restoration time objectives will affect the applicability for the distributed controlled DCS network architecture. It is concluded that using SONET DCS distributed control architectures to provide more complete survivability of a network would support numerous applications. Future services will demand a fault-tolerant network with complete survivability; this may only be reached through integration of SONET DCS distributed control architectures with other survivable architectures such as cell relay networks (e.g., supporting SMDS) and self-healing rings