Technologies towards broadband ISDN

It is argued that it is vital to form a sound strategy for developing broadband integrated services digital network (BISDN) technology and services and deploying them in the field, so that smooth migration from the existing network is accelerated. Three major steps in this context are to expand fiber networks into the subscriber loop area to provide broadband capabilities everywhere, to construct a universal digital network that facilitates smooth evolution from the existing network to the broadband network of the future through deployment of (SDH) synchronous digital hierarchy transmission systems, and to integrate both services and network components through introduction of asynchronous transfer mode (ATM) technologies. Development efforts now being carried out at Fujitsu and Fujitsu Laboratories along this line are described, and the impact on network construction and service offerings is indicated     

Evolution of metropolitan area networks to broadband ISDN

Broadband architecture and network evolution strategies based on interface standards emerging from the IEEE 802.6 MAN Committee and the American National Standards Institute (ANSI) T1S1 and CCITT Working Groups on broadband integrated services digital networks (BISDN) are outlined. The recent history of both the MAN and BISDN standards activities is traced, and some of the motivations behind specific developments are discussed. In the context, local area networks (LANs) and MANs are compared and contrasted, with special attention given to requirements specific to a public MAN. The convergence of the MAN and BISDN protocols is examined. The benefits of commonality between these two standards are described in terms of lower-cost network architectures, and terminal equipment is examined. It is shown that broadband networks can exploit the synergy between 802.6-based MANs and wider-area BISDN networks, and that 802.6-based MANs can gracefully evolve into countrywide networks using BISDN asynchronous transfer mode (ATM) switching. Example networks are used to illustrate the evolution proposals     

Migration to broadband ISDN

The current state of telecommunications in Japan is briefly discussed, with particular reference to broadband services. Experience with the migration from the analog telephone network to the present narrowband integrated services digital networks (ISDN) is described. Three strategies for the transition from narrowband ISDN to broadband ISDN are examined. The market-driven strategy is to replace existing metallic subscriber loops with optical media, wherever possible, even if only narrowband services are required, with the expectation that these subscribers will eventually use broadband services. The service-oriented strategy entails putting into place a flexible and multipurpose platform that would also allow HDTV distribution and bidirectional communications. Early installation of such a platform would allow for the early announcement of broadband services, which would in turn stimulate demand. The benefits and drawbacks of each of these strategies are discussed. The advance-investment strategy is to press ahead with the introduction of optical subscriber loops to accelerate technological innovation, even if the cost is somewhat high. Other issues that are important to the migration of broadband ISDN are noted     

World-wide standardization of broadband ISDN

A growing market demand for high-performance voice, data, image and video networks, coupled with advances in high-speed technologies has heightened interest in broadband ISDN (BISDN) throughout the world. Network providers, equipment manufacturers and standards bodies are working jointly to accelerate the definition of BISDN interfaces in anticipation of emerging market opportunities. BISDN is being designed as the foundation upon which to implement very flexible, high-bandwidth, high-performance networks. A multiplexing concept called asynchronous transfer mode (ATM), which can offer bandwidth on demand at rates exceeding 150 Mb/s, high-speed packet switching, and an efficient protocol which adapts existing information streams into the ATM format are key attributes of the emerging BISDN network standards. This paper reviews the motivations behind BISDN, explains its key attributes and challenges and discusses possible strategies for evolving today's network toward BISDN.     

Narrowband ISDN and broadband ISDN service and network interworking

For a significant period of time, B-ISDN will coexist with the 64-kb/s-based (narrowband) ISDN. The specification of a concept and the mapping functions employed for interworking between the two networks, in particular for voice services, is a major factor for the success of B-ISDN     

Satellite ATM for broadband ISDN

This paper presents the development of satellite ATM for broadband ISDN based on the Research in Advanced Communications in Europe (RACE) CATALYST project. The purpose of the project is to develop an experimental ATM satellite link for the future B-ISDN services, particularly for the interconnections of the ATM testbeds which are in the form of broadband islands developed in Europe. Then initial ATM based B-ISDN can be introduced by interconnections of these broadband islands. An evolutionary approach has been adopted in the development of the ATM networks that the CATALYST project has developed the equipment to be able to interconnect the newly developed ATM testbeds as well as the existing networks such as DQDB, FDDI and Ethernet networks. In March 1994, the project carried out an experiment on the second demonstratoras the Laboratories of Alcatel Telespace in Nanteere near Paris to demonstrate the capability of the satellite ATM connections supporting data, voice, video and multimedia applications. This experiment provided a real system demonstration of satellite ATM for B-ISDN. In the light of the experiment, this paper presents the model and architecture of the ATM satellite equipment, studies the relevant issues and the impact of ATM-via-satellite on the applications and the protocols, and evaluates of satellite ATM based on some measured and simulated results.     

Sprint's evolution to broadband ISDN

One telecommunications company's-Sprint's-transformation of their infrastructure architecture away from dedicated transmission facilities and toward high-bandwidth virtual facilities which will enable customers to construct transmission networks that can be reconfigured almost instantaneously is described. Sprint's current X.25, frame-relay, switched circuit, and private line services are reviewed. The evolving architecture that will, on a moment's notice, enable a customer to redirect his traffic among the networks as well as to dynamically expand and contract transmission bandwidth to any of the networks is discussed. The architecture will be based on frame-relay permanent logical links at the end of 1992 and move to ATM cell-based access in 1994 to 1995     

Heading towards an advanced signalling system for multimedia,multiparty services in broadband ISDN

Introduction of the broadband integrated services digital network (B-ISDN) will enable network users to make use of advanced multimedia, multiparty services. With this aim in view, RACE II project R2044, MAGIC, is investigating long-term signalling requirements, architecture and protocols for B-ISDN. New service concepts are being developed in MAGIC which will provide more flexibility when compared to narrowband ISDN (N-ISDN). The service requirements and other signalling requirements, such as the separation between call and associated connections at the network-node interface, are used to determine the distribution of functions over the network. The signalling protocols which are used to exchange the signalling information are subsequently developed. These signalling protocols are simulated to prove the performance and the feasibility of call handling concepts     

Narrowband and broadband ISDN CPE directions

Noting that ISDN customer premises equipment (CPE) is critical to the successful deployment of ISDN whatever the bandwidth, the author examines the market for narrowband and wideband integrated services digital network (NISDN and BISDN) CPE. He establishes the basic requirements for NISDN terminals and discusses terminal adaptors, digital telephone sets, screen-based telephony, workstations, customer premises networks, and CPE maintenance and upgrades. He examines the BISDN market and discusses the features and architecture of the terminals     

A new direction for broadband ISDN

The industry strategy to introduce broadband ISDN is addressed. This strategy is placed within a marketing context, and possible ramifications are considered. It is suggested that the current vision of a complex, multifeatured network rolling out in 1994 may be overly ambitious and still not meet end-user needs. An alternate strategy based on a minimal technical solution is derived and discussed     

New directions in signaling for broadband ISDN

User networks signaling is considered. The evolution of signaling protocols is outlined, analyzing the forces producing changes in the past. Emerging broadband switching technologies and services are discussed, emphasizing capabilities that might be required. A conceptual model for representing integrated-services digital network (ISDN) calls is presented as the basis for structuring a more flexible signaling protocol to meet the needs for a broadband environment     

Management of capacity and control in broadband ISDN

The trend towards integration of services onto a single network and the addition of accompanying control features has led to an increase in the complexity of functional signalling protocols. A continuing dramatic reduction in the cost of traffic-carrying capacity has meant that call control costs are becoming an increasingly significant component of the total network cost. In BISDN, the support of many diverse services may result in an excessive control cost. To avoid this potential problem, virtual paths may be used. Capacity may be reserved on virtual paths to simplify the set-up procedure for individual calls. One benefit of this approach is that the cost of establishing a virtual path is shared among all individual connections which subsequently use it. However, this reduced control cost comes at the expense of installing additional traffic carrying capacity. This paper describes techniques for the management of traffic carrying capacity and control mechanisms in BISDN and presents a cost-benefit analysis to determine policies for reserving capacity on virtual paths. Significant savings in the total BISDN cost can result from the use of virtual paths.     

A self-routing multistage switching network for broadband ISDN

A switching network that approaches a maximum throughput of 100% as buffering is increased is proposed. This self-routing switching network consists of simple 2×2 switching elements, distributors, and buffers located between stages and in the output ports. The proposed switching requires a speedup factor of two. The structure and the operation of the switching network are described, and its performance is analyzed. The switch has log₂N stages that move packets in a store-and-forward fashion, incurring a latency of log₂ N time periods. The performance analysis of the switch under uniform traffic pattern shows that the additional delay is small, and a maximum throughput of 100% is achieved as buffering is increased     

International standards for the broadband ISDN user-network interface

Recently, a series of international standards on broadband ISDN were approved in CCITT Study Group XVIII. These standards establish fundamental details on transmission, multiplexing and switching for broadband aspects of ISDN. This article reports on the current definition of the BISDN user-network interface. The UNI reference configuration, physical medium, rates, structure, ATM functions, and operations and maintenance functions are addressed with consideration given to open issues and the direction of future standards activities. Objectives for the UNI capabilities have generally been met with the current CCITT specifications. Some of the UNI physical layer ‘options’, however, potentially impose networking cost penalties.     

Broadband communication and its realization with broadband ISDN

In addition to narrowband services, future broadband networks will also include broadband services for applications like: high-speed communication of data, text and graphics person-to-person video communication, access to video information as well as broadcast of programs and data. Low terminal costs and service charges are essential with respect to a growing demand for new services, especially in the home. Broadband ISDN, to be developed on the basis of ISDN and using glass-fiber subscriber lines, will enable a wide range of applications satisfying the needs and requirements of the business and private sectors. The best technical solution from the aspect of user-friendliness and economy is to implement this broadband ISDN for all services with an evolutionary and flexible design. The broadband ISDN concept is not restricted to the public network and terminal equipment but also comprises private networks, information and program centers, etc. Many countries are pursuing the goal of this universal network for the future "information society". However, the approaches for setting up the broadband ISDN differ from country to country, depending on the particular technical and political situation. Standardization plays an important role with regard to "open broadband telecommunication", the worldwide trouble-free communication and information exchange of one party with any other.     

Experimentation on asynchronous switching techniques for broadband ISDN

This paper deals with a proposed implementation exploiting the new asynchronous transfer mode (ATM) multiplexing and switching techniques. In particular, the basic architectural and functional choices are outlined and various aspects are examined regarding the implementation of a switching arrangement using ATM switching techniques, giving some indication about its hardware and software architecture and the foreseeable system performance.     

Two years of experience with broadband ISDN field trial

The BERKOM project, which represents the largest broadband ISDN (BISDN) field trial in the world, is discussed. The objectives of the field trial are outlined. Three aspects of the test network are then addressed: system concept, system extension, and system experience. Tests demonstrated that the overall system performance met all requirements for telecommunication applications     

Bandwidth quantization and states reduction in the broadband ISDN

If a network supports only certain rates, we say its bandwidth is quantized. In a quantized-bandwidth network, a customer may be forced to use the next higher rate if the requested rate is not supported. The result is a higher blocking probability and a lower throughput. The throughput loss due to quantization is called the quantization loss, and its related issues are the focus of this paper. We show that the quantization loss is insensitive to capacity scaling and traffic-loading. More important, it is hardly as large as is thought. Even for a network, such as ATM, intending to support a continuous bit rate, bandwidth quantization can be a powerful tool for states reduction. States reduction is shown to be indispensable for solving many problems, such as routing and capacity planning, of a broadband network