Personalizing ISDN

It is argued that making integrated services digital networks (ISDNs) more popular among personal computer users is essential for ISDN to prosper. Users in offices, businesses, and at home form a large potential ISDN market. Existing ISDN interface modules such as ISDN adapter boards for personal computers, are limited to ISDN features and can hardly handle the various needs of personal users. An ISDN interface module for personal computers must be designed to handle various applications and provide any-to-any communications. An ISDN personal computer interface developed to handle digital and analog communication protocols and flexibly combine resources is described     

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.     

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     

ISDN: from custom to commodity service

With a toehold in specialized applications, ISDN is poised for takeoff as the all-digital telephony service affordable by everyone. ISDN has been on the worldwide telecommunications agenda for the last decade and is one of the most important junctions of the Information Superhighway. Despite early satire of the network as the Interface Subscribers Don't Need, operators have diligently brought it to market as an outstanding telephony service capable of revolutionizing users' lives. The ISDN options added by vendors to their product lines are costly because of low installed volume. And high tariffs deter many users who could get ISDN services in their area, however much they appreciate all its technical goodies. Still, from a technological point of view, ISDN is well prepared for mass-market deployment in commodity applications. It needs only a further push by operators (lower tariffs, better geographical coverage) to become in reality the Interface all Subscribers Definitely Need     

The value of ISDN for banking applications

US Bank's experience with a number of applications supported by Northern Telecom's DMS-100 integrated services digital network (ISDN) is discussed. Some of the applications that US Bank has been using, as well as some applications planned for near-term implementation, are described. The current applications supported by ISDN are the centrex telephone; message desk call receptionists; systems network architecture (SNA) host access; automatic teller machines; point-of-sale network; and wide-area networking. Future ISDN applications include support of loan approvals and service kiosks     

ISDN user-network interface management protocol

The author discusses an ISDN user-network interface management protocol. The protocol enables users to manage network services, operation (such as network reconfiguration and routing change), and maintenance. That the user equipment should be looked at from both user-of-service and manager-of-service perspectives is emphasized in a discussion of the relation of the user equipment to the Telecommunication Management Network (TMN). The current status of the ISDN UNI management protocol architecture studies in CCITT is reviewed, and problems specific to the ISDN environment are identified. The need to strengthen the convergence function to solve ISDN-specific problems is stressed. Examples of ISDN UNI management protocol applications are given     

Multi-rate ISDN

Multi-rate integrated services digital network (ISDN) is a new technology for providing dialed-up, circuit-switched, isochronous communications for bandwidths from 128 kb/s to 1.536 Mb/s (DS-1) or 1.920 Mb/s (CEPT-1). Multi-rate ISDN provides a simple way to extend ISDN network services to match the higher bandwidth requirements emerging for videoconferencing, multimedia, imaging, and other high-speed applications. Using this technology, network service providers can offer high-speed connectivity within the boundaries and benefits of existing, circuit-switched, central office and transmission equipment. Only minor changes are required in the operations administration and maintenance and provisioning (OAM&P) procedures associated with multi-rate ISDN, versus existing ISDN transmission and central office maintenance procedures     

Software Protocol for Handling ISDN in the Packet-Switched Network

The Integrated Services Digital Network (ISDN) provides basic architecture for existing, as well as future residential plus business communications. ISDN overlayed with CCS#7 of a digital PSTN (Public Switched Telephone Network) can be the ultimate, ubiquitous network for circuit switch (voice, data), packet switch (voice, data), and private line (voice, data) applications. Assuming that the present ISDN has to interwork in the present physically separate overlayed networks (voice and data), significant problems are expected to emerge for designing hardware and linking softwares for handling packet traffic. In this paper, the software-related problems, when ISDN packet distribution nodes have to handle an ISDN interface, will be outlined with an ISDN software protocol solution. An approximation of the delay involved in the telephone switching system which is part of ISDN processing as well as the delay for the interface gateways, the HOST computer nodes, and the LAN and WAN computer nodes will be identified and formulated to reflect the total performance measure defined. Major emphasis is given to flow and congestion control performance measures in the ISDN Gateways, which are analyzed and simulated with the assistance of the basic delay table transfer software model developed for the IMPS and gateways in the ARPANET, MILNET, and MINET. The performance evaluation of this basic ISDN interfacing software, which only involved one ISDN level, i.e., the HOST or gateway and its related subnetworks, is simulated on sections of these networks to illustrate its congestion control effectiveness. There are six mathematical software techniques to account for end-to-end delay, which form the basis for the solution to these ISDN software-hardware problems in the Interface Gateways connecting the electronic switch to the computer network components.     

Introduction strategies towards B-ISDN for business and residentialsubscribers based on ATM

It is argued that introduction strategies for B-ISDN with a clear evolutionary path to the future must be worked out. Two strategies are described, along with their early application. The first is mainly intended for business customers and offers an initial-phase asynchronous transfer mode (ATM) cross-connect functionality. The second is for residential users and initially offers POTS (plain old telephone service) and narrowband ISDN and analog TV services. Both solutions can easily be upgraded step by step to a full ATM-based B-ISDN     

Layers 2 and 3 ISDN Recommendations

The main feature of an ISDN user-network interface is the support of a wide range of service capabilities, including voice and nonvoice applications in the same network by offering end-to-end digital connectivity to a user. To handle the wide range of applications, a number of new features were developed and incorporated in the ISDN user-network interface layers 2 and 3 Recommendations. This paper reviews the current status of the ISDN user-network interface layers 2 and 3 Recommendations, with a special emphasis on new features developed and incorporated in these Recommendations.     

Design and Architecture of the High-Speed Digital Data Transmission System in NTT

Demand for high-speed wide-band telecommunication services is rapidly growing due to the remarkable progress in office, factory, and laboratory automation. These services are expected to be first introduced in leased circuits and then extended, to high-speed switched services. This paper presents the users' demands for such high-speed services and the NTT design concepts for the high-speed digital data transmission system (HDDTS) in NTT to provide such high-speed leased circuit service. The ISDN user-network interface is adopted. The basic high-speed pointto-point transmission service started in October 1984, and enhanced leased circuit service involving multiplexed interfaces and muitipoint circuits will be introduced in the fall of 1985.     

A Channel Access Structure for Wideband ISDN

To be fully integrated, the Integrated Service Digital Network (ISDN) arena is preparing an evolution from its current narrowband structure (at basic and primary access rates) to a futuristic wideband structure where access rates will be capable of supporting services beyond 100 Mbits/s. A wideband channel structure for ISDN, supplementing the narrowband channel standards, is thus needed. This paper presents a channel structure in which the access bandwidth is organized in a hierarchy of channels of increasing speeds. Channels at a given speed level accommodate services with specific bandwidth and holding time requirements. However, to improve performance, the access interface uses a control strategy whereby a service request at a given level can overflow to a lower level for access at lower bit rate. The performance, in terms of access delay and access throughput, of this access scheme is analyzed. Numerical results are provided for the special case of an interface with two levels of channels. These results show that a significant improvement in access performance can be obtained with the overflow mechanism of the access control discipline used.     

适配于ISDN的综合业务局域网设计

现有ＬＡＮ的传输能力在很大程度上可满足传输综合业务的要求，现有ＬＡＮ适配于ＩＳＤＮ的直接方法是在ＬＡＮ上实现ＩＳＤＮ功能，从而达到ＬＡＮ工作站与ＩＳＤＮ间业务的完全互通，在ＬＡＮ上实现ＩＳＤＮ功能的方案是：（１）在ＬＡＮ上增加综合业务传输接口，该接口不同于ＬＡＮ软件提供的接口，具有实时性，而且该接口的设计应使ＬＡＮ应用与综合业务应用间互相独立；（２）开发在工作站上与ＬＡＮ应用软件并发运行的综合业务     

Network of the future

Telecommunications networks of the future will exploit two new network architecture concepts that are currently being implemented, or soon will be. These are the Intelligent Network and ISDN, the Integrated Services Digital Network, which together will support a full range of voice, data, and image services that Information Age telecommunications users will demand. These new network architectures, operating synergistically with intelligence in terminal systems, will constitute a framework in which users and service providers will link together standardized functional components to create customized services. These components, along with interfaces and signaling protocols at the interfaces and within the network will result from continuing national and international standardization efforts. In the planning of these new architectures, a few major goals are of paramount importance: • the achievement of a flexible network structure in which functionality is distributed among the network components in a way which supports the timely and economic introduction of new services in response to user needs; • the establishment of industry standards at the interfaces between network elements such that service suppliers can choose among a set of available systems products in building their networks and avoid dependence on a small set of suppliers, • the development of standard user interfaces supporting signaling procedures which can provide the user with increased control of, and access to, services to satisfy his needs; Achievement of these goals will result in the realization of an Open Network Architecture. The ISDN and Intelligent Network architecture concepts are described in this paper.     

An introduction to TSAPI and network telephony

Discusses the integration of the telephone into the desktop work environment. This objective can be achieved in a number of different ways. The approach described uses the client-server model. Network telephony is a service that provides the capability to establish, answer, route, and terminate telephone calls under the control of applications on either desktop computers or servers resident in the network. It is accessed by applications via a standard programming interface (telephony services application programming interface, TSAPI) and utilizes a centralized server-based interface with the private branch exchange (PBX) to access the switching and telephone control services that the PBX provides. Creating a logical control link between the application software on the desktop computer and the telephone on the desk eliminates the need to physically connect the telephone to the desktop computer. The author distinguishes between the application programming interface and the network telephony service provider. The author assumes the services are provided by NTS R2.2 release and a PBX-based switching service. However, the author uses the term PBX to include switching services provided by key telephone or hybrid systems, PC-based telephony cards, or other appropriate technologies     

发展ISDN促进电信新业务的应用与普及

本文从ＩＳＤＮ的业务能力入手，讨论其在开发新业务方面的应用，并对我国电信网开放ＩＳＤＮ业务的装备条件和在我国推进ＩＳＤＮ的策略做了分析的探讨。     

Bandwidth Allocation Strategies in Wide-Band Integrated Networks

A common digital transmission facility in a wide-band integrated service digital network (ISDN) provides shared access to a community of heterogeneous users. Traffic demands from these users vary in their arrival rate, their service time, and their bit rate. In order for this type of communication system to handle its traffic demands with high efficiency and flexibility, a close control of access to the shared bandwidth is required. We model the system by a general multiserver queueing system where customers demand service from a random number of servers. If no waiting is allowed, this queueing model is readily analyzed, and various server allocation strategies can be studied. If the various access requests are queued for service, then the system calls for efficient strategies for allocating servers to waiting customers. In this case, exact analysis of the underlying queueing model becomes quite difficult. For this case, we present some analytic and simulation results of the performance of the system under several server allocation policies.     

Implementing ISDN in the United States

Planning for implementation of ISDN is proceeding at a rapid rate throughout the United States. Planning for nationwide deployment of common-channel signaling to support database access, as well as internode signaling for ISDN is also underway. This paper describes planning for trials and initial applications of ISDN and common-channel signaling for service starting in late 1986 through early 1988, as well as ISDN demonstrations, some already in operation. In addition, this paper discusses the network and regulatory environment for ISDN implementation in the United States, standards for the U.S. environment, and trials of transition services.     

Sockets++: a uniform application programming interface for basiclevel communication services

This article presents an enhanced application programming interface based on the well-known BSD Sockets paradigm. The major modifications made during the redesign of Sockets are as follows: using an object-oriented design that facilitates the introduction of new communication service functions and simplifies use and learning; using a new generic communication model that supports a wide range of traditional and advanced communication services such as OSI, Internet, ISDN, and ATM services; using an abstract message-passing concept to transfer service data across the interface which enables operating systems to apply copy-avoiding mechanisms; supporting multipoint communications and enabling applications to distinguish different data streams; supporting direct forwarding of incoming data streams to outgoing streams to yield better performance; avoiding platform dependencies so as to reduce modification costs when porting applications