B-ISDN: a technological discontinuity

The transition to B-ISDN from current networks represents a major technological discontinuity for the communications world. These discontinuities must be considered for the successful evolution of existing networks to broadband networks. The authors provide an overview of B-ISDN data transfer protocols and the services it will support. They discuss the effects of B-ISDN switching, network operations and management, signalling protocols and architectures, and networked computing     

UMTS integrated with B-ISDN

Since, by the turn of the century, a mobile terminal will be involved in 50 percent of all calls, it is critical that the integration of the fixed and mobile telecommunication systems succeeds. This will require that B-ISDN support some features necessary to provide mobility services to the users. In the scenario discussed in the present article, the UMTS base stations are connected to a B-ISDN local exchange using the same user-network-interface (UNI) as B-ISDN fixed network terminals. Therefore, many of the aspects discussed in the article are related to the UNI     

Supporting applications with network intelligence and B-ISDN

The year 2000 is swiftly approaching and, with all the expectations it brings, many telcos are gearing up to provide telecommunications networks that will satisfy the majority of demands that new feature-rich applications will place upon them. To some people, supporting application requirements for a telecommunications netwrok might mean adding more intelligence to the network. Others may crave to transmit data at faster speeds, communicate more freely on the move, or be able to mix and match the appropriate network infrastructure as they, or their applications, choose to do so. These diverse application requirements are shaping the strategies being pursued by telcos to deliver integrated telecommunications networks for the next millennium. After looking back at some of the developments taking place within the broadband and network intelligence domains, this paper summarises some of the application and service requirements that must be addressed when building future telecommunications networks. From the plethora of technical proposals aimed at developing the necessary environment to fulfil these requirements, this article explores the alternatives. Of course, for all of these alternative routes there will be many questions, technical or otherwise, that yet remain unanswered. Some of these issues will be discussed and various options will be considered to provoke thought or socialise possible solutions.     

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。     

光纤用户环路的现状和关键技术

本文简单介绍了光纤用户环路的结构,详细描述了美国、日本、英国和德国等通信发达国家在光纤用户环路方面的研究现状,并指出了光纤用户环路的关键技术。     

B-ISDN architecture and protocol

The authors discuss the architecture and protocol for broadband ISDN (B-ISDN) based on the CCITT standards. The discussion attempts to address the general concept of B-ISDN architecture and protocol and, whenever possible, present alternatives and the rationale for decisions in the selection of the protocol. B-ISDN is presented as a network evolution, and the impact of the asynchronous transfer mode (ATM) on the network is described. The role of virtual channel and virtual path in B-ISDN is discussed. The B-ISDN protocol structure and lower layer functions comprising the physical, ATM, and adaptation layers are presented, and the tentative trends of signaling and traffic control for the B-ISDN are delineated     

欧洲B－ISDN试验网：TRIBUNE

ＴＲＩＢＵＮＥ计划是欧洲先进通信技术研究计划（ＲＡＣＥ）的一部分。此计划的目的是在欧洲为先进的通信业务，特别是宽带综合业务数字网（Ｂ－ＩＳＤＮ），建立公共基础设施。本文将简要介绍该计划的概况。     

Medical applications in a B-ISDN field trial

The need for high-speed communications networks that enable users to access remote resources will accelerate the development of many innovative distributed applications in the health care industry. A B-ISDN field trial network has been developed in North Carolina as a multiservice testbed for advanced applications research and development. The paper describes the research on two high-performance medical applications, the network equipment, and terminal interface adapters that have been implemented to serve those applications, and the insights that have been gained from this field trial experience     

DIRSMIN: a fault-tolerant switch for B-ISDN applications usingdilated reduced-stage MIN

We have developed and analyzed a dilated high-performance fault-tolerant fast packet multistage interconnection network (MIN). This new switch, (d,d')-DIRSMIN, uses dilation to improve performance and fault-tolerance of a network. The links at the input and output stages of the dilated banyan-based MIN are rearranged to create multiple routes for each source-destination pair in the network, after removing the first stage in the network. These multiple paths are link- and node-disjoint. This new MIN can provide low packet-loss probability and high reliability with very little hardware overhead, compared to d-dilated banyan networks (BN). Fault tolerance at low latency is achieved by transmitting multiple copies of each input-packet simultaneously using different routes. A multiple-priority scheme allows alternate paths to be explored simultaneously, which results in higher throughput and reliability under both fault-free and faulty conditions. This guarantees that high throughput is maintained even in the presence of a fault. Throughput is analyzed using analytic and simulation methods; this new design has considerably higher performance in the presence of a permanent faulty switching-element (SE) or link, in comparison to dilated networks. Under non-faulty conditions, both analytic and simulation results show that a (d,d)-DIRSMIN performs better than the original dilated BN with the same SE complexity. We analyze the network reliability and show that the new design has superior reliability compared to competing proposals. In particular, this new design is considerably better than the SEN+, the best known thus far     

ATM-layer OAM: principles and open issues [B-ISDN]

The principles of operation and maintenance (OAM) for broadband ISDN access, as well as some general OAM rules for an asynchronous transfer mode (ATM) network, are discussed. Standardization of the OAM functions and mechanisms for the ATM layer, which is based primarily on CCITT Recommendations, is considered. Issues regarding OAM flow at the ATM layer are examined. It is seen that although references can be made both to basic and primary rate ISDN, new solutions are necessary for the OAM of B-ISDN. Issues requiring further study are identified     

利用软件工程的方法开发B－ISDN的用户／网络信令

Ｂ－ＩＳＤＮ的用户／网络信令是ＡＴＭ（异步转移模式）交换机软件的重要组成部分，本文简要介绍了利用软件工程的方法来开发Ｂ－ＩＳＤＮ用户／网络信令的具体实现方法。     

广播电视宽带综合数字业务网的实现

数字技术为广播电视带来了一场深刻革命的同时 ,人们又发现了这场革命更广更深远的意义 ,那就是这场革命的意义不单是数字电视本身 ,而是它为任何数字信息的广播开辟了新的航线 ,通过这条航线 ,数字广播技术将在末来信息社会中占有重要的地位。除数字电视之外 ,数据广播和借助上行通道实现的交互式业务是数字广播的两大应用方向 ,典型的应用可包括多媒体广播、软件下载、Internet接入和交互式电视等。DVB和 ATSC的数据广播和交互业务标准在内容上无原则差别 ,从制定和批准时间上 ,DVB领先 ,因此本文基本以DVB为准加以介绍。近年来 ,广…     

宽带综合业务数字网的发展与关键技术

90年代世界较发达国家都在加速研究开发宽带综合业务数字网(B-ISDN),以及为最终实现B-ISDN而进行网络演变和宽带业务应用等研究工作。本文概要介绍了包括中国在内的几个国家B-ISDN的发展策略和进展情况,以及B-ISDN关键技术。     

Service-affecting optoelectronic failures in FITL systems:downtime, repair actions, and maintenance expenses

This paper provides a quantitative examination of lifecycle cost versus operating environment for fiber-in-the-loop (FITL) systems. It focuses on reactive maintenance due to service-affecting failures of optoelectronic elements. The scope is limited to passive point-to-multipoint star local networks, engineered to deliver narrowband telecommunication POT's services, with hybrid fiber/copper architectures (i.e., the customer's terminal equipment (TE) is connected with symmetrical copper pairs to the optical network unit or ONU of the FITL system). The influence of service-affecting failure rates, times to repair, and the various temperature environments faced by the optoelectronic equipment is evaluated in terms of: (i) service downtime; and (ii) the number of repair actions and maintenance expenses due to service affecting failures on the optoelectronics-related elements. The author estimates some $60 expenses, per line during a 20 year lifecycle, if the ONU is in a partly controlled temperature environment, and some $170 in an uncontrolled temperature environment. A downtime, per line per year, lower that 60 minutes can be achieved in both types of environment. Placing the ONU in a partly controlled environment, however, enables a 100% increase in the times to repair or, alternatively, some 90% decrease in the downtime     

Satellites in UMTS and B-ISDN: status of activities andperspectives

Satellites are no longer seen as an alternative to a terrestrial mobile telecommunications system or the (optical-fibre-based) integrated broadband communications network. Instead they are now being considered as one of the components of the Universal Mobile Telecommunications System being developed within the European Union's RACE Programme for the next century and as a component of the broadband ISDN. This paper discusses the role played by satellites in these systems and the issues which have to be addressed     

Controlling congestion in B-ISDN/ATM: issues and strategies

The high-level goals of a congestion control architecture are outlined. The controls are discussed in detail, focusing on the set of controls exercised by the network and the functionality needed at the network access and in the internal network elements. The end system controls are discussed only to the extent that they can benefit from the available network controls. The motivation for the suggested controls is discussed by describing their use for selected traffic types. Example traffic types and the use of some of the controls to support these traffic types in an integrated environment are examined     

Frame relaying as a common access to N-ISDN and B-ISDN dataservices

Widespread use of personal computers (PCs) and PC networks is leading to a strongly increased demand for WAN data services in terms of number of accesses and required bandwidth. Narrowband ISDN (N-ISDN) and broadband ISDN (B-ISDN) have the potential to satisfy, respectively, the existing and developing requirements. However, a flexible evolution path needs to be identified for the provision of ISDN access facilities. Frame relaying and frame switching are prime candidates for such a common access facility, although not necessarily intrinsic B-ISDN data services. The article gives an overview of frame relaying and frame switching as possible candidates for harmonized access to N-ISDN and B-ISDN. Pre-ISDN, N-ISDN, and B-ISDN services with their characteristics in terms of cost and performance are first described. It is shown how frame relaying and switching are positioned with respect to the identified service requirements. Then some examples are given of selected scenarios, and the role played by specifically frame relaying to provide access to B-ISDN services, offering at the same time a seamless evolutionary path from N-ISDN to B-ISDN. The position of frame relaying and switching is discussed first in respect to application requirements, and then in architectural terms. Frame relay (and frame switching) services are then identified as services that provide the necessary low threshold and short lead time for rapid market penetration, in order to allow applications to indirectly take advantage of the benefits of ATM services     

BCSM SWITCH FOR B-ISDN A NEW HIGH-PERFORMANCE SWITCHING ELEMENT

This paper proposes a new high-performance switching element with the new shared-memory queuing policy, which is called blocked-cell shared-memory (BCSM) queuing. As the name means, instead of buffering all cells through them, the BCSM switching elements only buffer the blocked cells at their input ports. Theoretic analysis results under the uniform traffic model prove that BCSM switching elements have better performance than shared-memory switching elements.     

ATM: customer needs in the transition to B-ISDN

The development of the broadband integrated-services digital network (B-ISDN) is part of the continuing evolution of the telecommunications network. The author considers the expected rate of increase in information-carrying capacity to the general public and its needs for interfacing and service. He proposes a technique of shaping/policing the channel capacity which will be easily understood by both user and network provider. Finally the uncertainties that remain in the way that applications may exploit the ATM network and the consequent different needs for signalling and control have been highlighted