Whatever happened to ISDN?

The integrated services digital network (ISDN) standard was defined in 1972 yet the progress towards its implementation has been very slow and very little is yet on offer to the consumer. The author looks at the vision where the concept of ISDN transforms the telephone network into a transport mechanism for all communications needs. Services offered by ISDN are discussed as are implementation and tariffs     

Integrating ISDN and OSI: an example

A successful multivendor trial demonstrating the integration of Open Systems Interconnection (OSI) and integrated services digital network (ISDN) technologies is discussed. The planning, staging, and results of this trial, which demonstrated ISDN as a viable transport technology for OSI data applications, are detailed. The technical requirements to be fulfilled and the initial plans are outlined. The actual configuration used is described, and the results are summarized     

Signaling System No. 7 ISDN User Part

The integrated services digital network (ISDN) user part of Signaling System No. 7 defines the signaling protocol which supports the establishment, supervision, and release of voice and nonvoice calls over circuit-switched connections between ISDN terminations of digital subscriber access lines. This paper gives an overview of the ISDN user part protocol, as defined in CCITT Recommendations Q.761-Q.766 [1], in terms of the signaling functions and procedures provided to support call and connection control in an ISDN, and in terms of the information elements and signaling messages that are used by the signaling functions in ISDN exchanges to communicate.     

ISDN applications at Tenneco Gas

The evolution from analog to integrated services digital network (ISDN) telecommunication services at Tenneco Gas and the features of its telephone system are described. The results of implementing ISDN in data operations are examined. The benefits of ISDN for Tenneco are briefly summarized     

Support of Existing Data Interfaces by the ISDN

During the past decade, the opportunity has arisen to economically combine data and voice services onto a single system, the integrated services digital network (ISDN). Studies in CCITT have led to the production of a set of Recommendations covering aspects of the ISDN, including the customer terminal interface. Inevitably, there are significant differences between the customer terminal interfaces recommended for dedicated data networks and that proposed for the ISDN. To ensure a smooth transition towards the introduction of ISDN based services, the CCITT have published recommendations describing how existing terminal interface designs may be connected to an ISDN. These recommendations are the subject of this paper.     

Integrated voice and data communications overview

The author reviews architectures and traffic characteristics for voice and data communications, and addresses important issues in integrated voice and data communications. He discusses some possible methods of integrating voice and data and presents an example of implementing integrated voice and data communications. He considers ISDN (integrated services digital network) as a vehicle for supporting integrated services including voice and data as well as image and video. Although the concern is mainly with switched networks, some of the concepts discussed are applicable to both switched and special-services networks     

Network and System Architecture: The Integrated Approach to ISDN in the UT Line

The paper presents an approach to ISDN suitable both for a pilot service, to be carried out in the near future in Italy, and for long-term developments with a high degree of penetration of ISDN setvices. Integration of ISDN services in the digital telephone exchange "UT" has taken place at all levels: system architecture, subscriber access structure, circuit connecting network, transmission links, call processing, and 0 & M functions. We also describe a new protocol that facilitates the dialog between exchange modules and between different exchanges for the data service. It is suitable for implementing packet transit switches with low complexity, high throughput, and low transit time. A special peripheral-handling processor handles the most repetitive functions of the protocols both in the local exchange and in other parts of the network, while the exchange central processor performs the ISDN call-handling functions; the same peripheral processors and the same module processor are used for both ISDN and telephone services. Finally, the paper shows how this architecture can evolve to include new wide-band services and new techniques to implement high-capacity fast packet switches.     

Application profile for ISDN

The authors examine some key data processing applications to be used in conjunction with the voice and facsimile services as a platform for deploying ISDN (integrated services digital network) in North America. Special emphasis is placed on the emerging standards of both Accredited Standards Committees (ACS) T1 and X3 in an attempt to harmonize the computer and telecommunication industries towards providing the user with an integrated platform that is vendor-transparent and ubiquitous. This generic platform, which spans a large spectrum of businesses, is presented as a base context for defining user-specific needs and incubating the applications that directly relate to businesses. Distributed transaction processing, electronic data interchange, information retrieval, electronic mail, and file transfer together with seven supplementary services for voice and G4 facsimile are proposed for ISDN deployment in the marketplace. The authors describe how the relevant standards may be exercised through the various ISDN channels and emphasize the value of the North American ISDN User's Forum for commercializing this platform     

CITT E.700 recommendation series-a framework for trafficengineering of ISDN

Traffic engineering of ISDN (integrated services digital network) has become a key area of CCITT recommendations since 1985. The authors report on the first recommendations formalized in a dedicated series on ISDN traffic engineering, the CCITT E.700 series of recommendations. The authors also report on the ongoing work towards an extension of the series to cover integration of mobile services into ISDN, the E.750 series. Future directions related to such emerging issues as intelligent network services and broadband-ISDN/ATM (asynchronous transfer mode) are also reviewed     

Current role and future evolution of the ISDN Signaling system inNTT's network

The current role of the integrated services digital network (ISDN) Signaling System is examined, covering general features of the ISDN protocol, functionalities supporting ISDN services, and functionalities supporting existing services. The Signaling System No.7 (SS7) network and its operation are described. The future evolution of the ISDN signaling system is discussed     

Switching System Software Design for ISDN

The ISDN offers various services through multipurpose digital subscriber lines. The switching program for the ISDN should be so designed as to realize the control of various voice and nonvoice services and provide for developing service enhancement. To attain the goal, the ISDN services are classified hierarchically and each category is allocated to appropriate network nodes for implementation. As a result, the local switching program provides an out-slot subscriber line signaling capability and call connection with appropriate compatibility checking including a check for access capability to communications processing nodes. The switching program modules specific to analog services and those specific to digital services are separated to allow the use of the existing program file and to afford easy program design and maintenance. Remote-controlled switching is a suitable means for an economical introduction of the ISDN services to low traffic density areas. Special routing and reliability arrangements as well as the program structure for a remote-controlled switch are discussed.     

Network control method and human-machine interface design for ISDNmultimedia terminals

A human-machine interface has been created for an integrated services digital network (ISDN) network control unit (I-NUU). I-NUI is a sophisticated terminal device that allows a voice communication channel and two data channels to be connected through an ISDN I-series interface. ISDN communication functions and network control operations were analyzed to determine the required characteristics of I-NCU. I-NCU features the minimum number of control buttons and a liquid crystal display. Visual and audible information are used to keep the operator fully informed about the state of the communication channels     

ISDN: a snapshot

A snapshot of the present status of ISDN (integrated services digital network) is presented in terms of standardization efforts, field trials and demonstrations, implementations and services, and equipment and devices. A review of opinions and controversies as well as future trends is also given. The authors emphasize the importance of the worldwide standardization effort and discuss the organizations that are responsible for establishing such standards. It is pointed out that, with the limitation and inflexibility of the narrowband ISDN and the broadband ISDN, issues for higher-rate services have become prominent. For broadband services, the problem is not merely increasing the speed of the operation. It affects the compatibility of switching technology, the workability of the local loop arrangement, the availability of rate adaption, and the efficiency of bandwidth utilization. Although some basic principles of narrowband ISDN can be carried to broadband ISDN, the technology is quite different. For example, the interconnection and transmission problems of video, HDTV, (high-definition television), and high-speed data are different from those of voice. Thus, the standard 64-kb/s B channel itself, the fundamental rate of ISDN transmission, appears inadequate for wideband services. At present, the solution is to establish the multiples of 64 kb/s for accommodation of broadband or higher rates     

Implementation in Japan [ISDN]

INS-Net, Nippon Telegraph and Telephone's (NTT's) commercial integrated services digital network (ISDN) service, is described. There are two types of INS-Net service. INS-Net 64 provides basic rate interface service, and INS-Net 1500 provides primary rate interface service. The implementation of INS-Net and the promotion, application, and penetration of ISDN services are discussed. It is argued that as the number of useful applications grows, the number of subscribers will rise accordingly, particularly among business users. This increased volume of both applications and users will in turn lead to lower ISDN CPE costs, and will make ISDN an indispensable means to business activities in the 1990s     

Implementation of a broadband integrated services hybrid network

The issues involved in the design of a broadband integrated services digital network (B-ISDN), that utilizes optical fibers in the subscriber loop, are considered. A hybrid scheme that provides integrated access to ISDN and broadband services by delivering voice/data signals in a digital format while using an analog format for full-motion video services to subscribers is proposed. The discussion covers planning for a B-ISDN, the system concept, implementation, the loop fiber network, subscriber equipment, and cost comparison and analysis     

Bell Canada ISDN Trial Plans

After years of work by the CCITT and other standards bodies, the ISDN concept has reached the stage where manufacturers are announcing the availability of ISDN network and terminal products. Bell Canada has responded to this development by planning an extensive ISDN trial program, including access-loop verification, switch hardware and software verification, and, finally, customer market trials. This trial program will permit Bell Canada to refine the technology and services to best meet customer needs. The trial program is only the most recent manifestation of the evolution towards ISDN through digital network modernization. An early move towards digital technology within Bell has already paid substantial dividends in terms of new services and revenues. These services, and the emerging ISDN-based service opportunities, are highlighted in this paper.     

ISDN standardization

The history and achievements of ISDN (integrated services digital network) standardization in the CCITT are reviewed. Two of the most important developments, ISDN basic and supplementary services and broadband ISDN, are focused upon. The underlying concepts in the discussions of ISDN standardization are briefly explained     

Real-time mixes: a bandwidth-efficient anonymity protocol

We present techniques for efficient anonymous communication with real-time constraints as necessary for services like telephony, where a continuous data stream has to be transmitted. For concreteness, we present the detailed protocols for the narrow-band ISDN (integrated services digital network), although the heart of our techniques-anonymous channels-can also be applied to other networks. For ISDN, we achieve the same data rate as without anonymity, using the same subscriber lines and without any significant modifications to the long-distance network. A precise performance analysis is given. Our techniques are based on mixes, a method for anonymous communication for e-mail-like services introduced by D. Chaum (1981)     

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.