宽带综合业务数字网技术讲座

近年来，国外电信发达国家纷纷进行了有关ＡＴＭ的现场试验，并逐步向商用化发展。一些交换机制造厂家和大、中、小计算机公司也推出了ＡＴＭ设备，竞相占领电信市场。我国在几个大城市也开始了ＡＴＭ的试验。ＡＴＭ是构成宽带综合业务数字网的技术基础，了解相关技术演进是非常必要的。本讲座将陆续向读者介绍有关Ｂ－ＩＳＤＮ基本概念及其提供的业务，Ｂ－ＩＳＤＮ传送手段－ＡＴＭ，Ｂ－ＩＳＤＮ信令，Ｂ－ＩＳＤＮ国际标准化的发     

从现有通信网向B－ISDN过渡的第一步──帧中继

文章分析和介绍了帧中继保持了分组交换网价格低和网络灵活的优点，它简化了现有分组技术，有效地解决了容量和速率的问题，能支持现有的公用分组网；将来通信网向Ｂ－ＩＳＤＮ过渡，采用ＡＴＭ技术，它仍可对用户进网业务提供服务；而且帧中继容易实现，所以是向Ｂ－ＩＳＤＮ过渡第一步的平稳而可行的技术。但由于其速率仍受到限制，不能支持话音和图象，所以不能直接过渡到Ｂ－ＩＳＤＮ。     

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。     

从现有通信网向B—ISDN过渡的第一步——帧中继

文章分析和介绍了帧中继保持了分组交换网价格低和网络灵活的优点，它简化了现有分组技术，有效地解决了容量和速率的问题，能支持现有的公用分组网；将来通信网向Ｂ－ＩＳＤＮ过渡，采用ＡＴＭ技术，它仍可对用户进网业务提供服务；而且帧中继容易实现，所以是向Ｂ－ＩＳＤＮ过渡莓一步的平稳而可行的技术。但由于其速率仍受到限制，不能支持话音和图象，所以不能直接过渡到Ｂ－ＩＳＤＮ。     

向宽带综合业务发展的世界通信技术

本文简介了宽带通信业务在美国等发达国家的发展情况以及目前提供宽带通信业务的手段。综述了支持宽带通信业务的新技术。对支持宽带通信的网络进行了前景预测和标准化情况介绍。另外，还介绍了窄带综合业务数字网（Ｎ－ＩＳＤＮ）向宽带综合业务数字网（Ｂ－ＩＳＤＮ）的发展、虚通道（ＶＰ）的应用以及异步转移模式（ＡＴＭ）为基础建立全国性Ｂ－ＩＳＤＮ等开发应用实例。     

B—ISDN展望与DQDB

本文首先首要简要叙述了将成为未来Ｂ－ＩＳＤＮ核心技术的ＡＴＭ，然后详细阐述了作为向Ｂ－ＩＳＤＮ过渡的城域网标准－－ＤＱＤＢ网的原理，包括其拓朴结构，节点功能体系，帧结构和网络协议。     

ATM技术──B－ISDN的基础

ＡＴＭ技术──Ｂ－ＩＳＤＮ的基础谭淑贞编者按目前的通信网正逐步向宽带化、综合化和智能化方向发展。Ｂ－ＩＳＤＮ（宽带综合业务数字网）是未来通信网的发展方向，而ＡＴＭ（异步转移模式）是实现Ｂ－ＩＳＤＮ的基础。为了使广大读者对ＡＴＭ技术有一个基本的了解，本...     

建设ISDN应注意的几个技术问题

为了提供多种信息，许多发达国家早就在搞综合数字风（ＩＳＤＮ）了。先是窄带的Ｎ－ＩＳＤＮ，进而是宽带的Ｂ－ＩＳＤＮ。预计到２０００年前后，Ｂ－ＩＳＤＮ将正式投入罗国对于ＩＳＤＮ也 重视，计划到２０１０年要实现相当规模的Ｂ－ＩＳＤＮ。建设ＩＳＤＮ，有很多技术问题，本文只对几个主要的，例如参考结构、ＩＳＤＮ的信令、ＡＴＭ（异步传送模式）及ＩＳＤＮ与各方面的配合作简要介绍。     

建设ISDN应注意的几个技术问题

为了提供多种信息，许多发达国家早就在搞综合业务数字网（ＩＳＤＮ）了。先是窄带的Ｎ—ＩＳＤＮ，进而是宽带的Ｂ—ＩＳＤＮ。预计到２０００年前后，Ｂ—ＩＳＤＮ将正式投入应用。我国对于ＩＳＤＮ也很重视，计划到２０１０年要实现相当规模的Ｂ－ＩＳＤＮ。建设ＩＳＤＮ，有很多技术问题，本文只对几个主要的，例如参考结构、ＩＳＤＮ的信今、ＡＴＭ（异步传送模式）及ＩＳＤＮ与各方面的配合作简要介绍。     

C3本地B—ISDN规划方案的探讨

结合达川地区实际情况，对Ｃ３本地Ｂ－ＩＳＤＮ网规划方案的原则，现有通信网向Ｂ－ＩＳＤＮ网过渡的方法，步骤及相关问题进行了探讨。     

Traffic management for B-ISDN services

A set of asynchronous transfer mode (ATM) bearer service categories, differentiated in terms of quality of service (QOS), that will support the large spectrum of applications expected in broadband integrated services digital networks (B-ISDN) is defined. The evolution of applications and the traffic requirements in B-ISDN/ATM networks are described, and the evolution of network services to address these requirements is discussed. The definition of ATM bearer service categories necessary for the economical support of initial applications and evolution to future B-ISDN services is proposed. The elements of the ATM traffic management strategy to support these service categories are presented     

ATM公平排队服务算法

异步转移模式ＡＴＭ作为一种新的交换和复接体制，已经被国际电联ＩＴＵ挑选为宽带综合业务数字网Ｂ－ＩＳＤＮ的核心技术。ＡＴＭ技术的主要目的是使数据业务、视频业务、话音业务等能在统一的全数字网络中实现传输和交换，同时提供灵活简捷有效的动态资源分配。文章在说明通信业务各自千差万别特征的基础上，进行业务归类，并给出几种公平排队服务算法。     

B-ISDN and the OSI protocol reference model

The evolution of public telecommunication networks toward broadband integrated services digital networks (B-ISDNs) is presented. The asynchronous transfer mode (ATM), which supports B-ISDNs, and the B-ISDN protocol reference model are discussed. It is shown that the service offered by the ATM layer in the B-ISDN protocol reference model is equivalent to the service offered by the OSI physical layer. It is also shown that the service offered by the ATM adaptation layer (AAL) type 3/4 is similar to an OSI data link service. The emergence of the metropolitan area network (MAN) standard as an intermediate support for broadband services and the similarities between the DQDB MAC and the AAL type 3/4 in its connectionless mode are discussed     

Developing a cohesive traffic management strategy for ATM networks

The background and some of the rationale for the development of an asynchronous transfer mode (ATM) traffic management framework to support the wide variety of services to be carried over the B-ISDN are discussed. The advantages of statistical, as opposed to deterministic, multiplexing are examined. Given the anticipated B-ISDN service characteristics, two classes of quality of service are defined based on cell delay and cell loss. The key ATM traffic management tools are reviewed. These tools are broadly classified as either preventive, limiting the total amount of traffic admitted to the network in order to virtually eliminate probability of cell-level congestion, or reactive, assisting the network and individual connections to avoid the onset of congestion and minimize its severity when it does occur. A strategy for the initial introduction and the long-term evolution of an ATM traffic management framework is described     

Integrated open service node for active networks and services

The changing business scenario for telecommunication services requires higher levels of openness compared to current technologies. The realization of a programmable and open network intelligence fosters the transition toward an open telecom market. This extended openness is requested to allow flexible component-based service integration; extended control/management capabilities are needed for new electronic business infrastructure, more service personalization and programmability, and integration and management of heterogeneous networks (Internet/B-ISDN/mobile, etc.). We present an integrated architecture for active and programmable networks and services based on the concept of an integrated service node. We study the business point of view, the B-ISDN/ATM point of view, and the Internet point of view. Each of these technologies is supported by an adapted and adaptive service node to introduce advanced service composition, control, and management capabilities. We present a possible implementation infrastructure, and discuss related issues     

B-ISDN中的无连接业务

以ATM交换为基础的B-ISDN提供高速、面向连接、分组长度固定的信元交换.当代PC和高速LAN的发展需要面向连接的ATM网络传输无连接业务.本文重点介绍ATM网络中无连接业务的分类、协议结构和具体实现形式.     

ATM与帧中继互连技术

ＡＴＭ技术是ＩＴＵ－Ｔ推荐的Ｂ－ＩＳＤＮ交换技术，而帧中继在提供广域网业务方面很成功。因此，在ＡＴＭ发展的初期不可避免地会与帧中继技术并存。本文阐述了ＡＴＭ与帧中继网络互加和业务互连的相关技术及其存在的问题。     

多通道SAR层信元传输技术研究

ATM是宽带综合业务数字网的主要实现技术。文章分析了ATM协议栈中SAR层工作原理,根据AAL5业务SAR层对数据的处理过程,提出了两种基于FPGA的多通道SAR层信元拆分技术的解决方案;分析比较了两种方案实现过程及对内存空间的使用情况,指出了各个方案适用的场合,对基于FPGA的ATM协议的开发及替代专用通信处理芯片具有重要意义。     

ATM通信技术

概述了ＡＴＭ通信技术的信元结构、交换方式、协议模式和拥塞控制等，指出了ＡＴＭ是Ｂ－ＩＳＤＮ的基础，已成为当今通信发展的方向。     

Evolving from narrowband [ISDN]

A nodal system architecture developed by Nippon Telegraph and Telephone (NTT) that will allow stepwise evolution to broadband integrated services digital network (B-ISDN), starting from the current nationwide narrowband integrated services digital network (N-ISDN) system in Japan, is discussed. The status of the current N-ISDN and the requirements for B-ISDN as the next step after N-ISDN are discussed, followed by a scenario for the evolution of B-ISDN from N-ISDN. A plan is outlined for the first ATM switching service for high-speed data transfer and a nodal system architecture permitting easy evolution to full B-ISDN