Layer 1 ISDN Recommendations

In the framework of the I-series of Recommendations, layer 1 specifications for ISDN user-network interfaces are given in Recommendation I.430 for the basic access(2B + D)at 144 kbits/s, and in Recommendation I.431 for the primary access at 1544 and 2048 kbits/s. The former Recommendation contains a completely new set of procedural, functional, and electrical characteristics whose definition was started during the last CCITT Study Period and is expected to be completed by the end of the present CCITT Study Period. Moreover, the latter Recommendation is largely based on functional and electrical characteristics of existing Recommendation G.703, which gives specifications for the physical/electrical characteristics of the hierarchical digital interface.     

CCITT Recommendations on the ISDN: A Review

This paper gives a brief overview of the I-Series of Recommendations on the integrated services digital network (ISDN) developed by the International Telephone and Telegraph Consultative Committee (CCITT). This set of Recommendations is printed in the CCITT "Red Book." The I-Series Recommendations represent the first major step towards worldwide harmonization of the fast-growing digital network capabilities in support of multiservice (voice, data, and image) user applications. Over 25 different Recommendations set up standard guidelines and features for service capability, network architecture, and user-network interfaces in the ISDN.     

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     

Evolution of ISDN towards broadband ISDN

Worldwide activities to evolve integrated services digital network (ISDN) into an optical-fiber-based universal broadband network have resulted in the first baseline documents, such as CCITT Recommendation I.121. The asynchronous transfer mode has been established as a key element of broadband ISDN (BISDN). The adoption of the G.707-709 recommendations on the new digital transmission hierarchy will also strongly influence further BISDN development. The author presents the current state of the BISDN discussion, especially within CCITT, briefly addressing broadband services and then concentrating on the user-network interface, as its definition is of utmost importance with respect to the introduction of a worldwide unique BISDN. Network scenarios and evolution and interworking aspects of the arising broadband realizations are also addressed     

Telemedicine and ISDN

The advantages of using integrated services digital networks (SDNs) as an infrastructure for telemedicine applications are discussed. The applications, developed in a Norwegian Telecom Research project, are grouped according to their use in the health services: telediagnosis, distance learning, medical information, and administrative health information. The telemedicine applications are reviewed, and a number of ideas for further development of such applications based on ISDN technology are proposed     

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     

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     

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     

ISDN网络终端NT2的设计与实现

详细报告一种ＩＳＤＮ的第二类网络终端设备ＮＴ２的硬件和软件设计与实现,包括硬件总体设计方案,基本速率接口硬件模块设计,交换模块硬件设计,时钟模块的硬件设计,其群速率接口模硬件设计。物理层软件设计,ＬＡＰＤ协议软件设计,Ｄ信道网络层协议软件设计。     

N—ISDN第2类网络终端NT2的研制

介绍了ＮＴ２作为Ｎ－ＩＳＤＮ中不可或缺的网络终端设备所起的作用,以及它的总体硬件、软件设计方案。该设计的ＮＴ２可提供多达９６个２Ｂ＋Ｄ接口和２个３０Ｂ＋Ｄ接口,采用灵活的组合方式,任何两个接口之间均可实现无阻塞交换。     

ISDN protocol architecture

IT IS NOW widely recognized that the Integrated Services Digital Network (ISDN) concept is providing a useful framework for the development of future telecommunications networks and services. An ISDN can be regarded as a generalpurpose digital network capable of supporting (or integrating) a wide range of services (voice and non-voice) using a small set of standard multipurpose user-network interfaces. Relevant CCITT Recommendations (or standards) on ISDN interfaces were expected to be available in 1984, the final year of the current study period. This paper reviews CCITT progress on the architectural studies of protocols associated with ISDN's, in particular, the ISDN Protocol Reference Model being developed by Study Group XVIII. This Model, based on the concepts and principles of the ISO/CCITT Open Systems Interconnection (OSI) Reference Model, aims at providing a unified framework for modeling ISDN multiservice communications and capabilities. The new Model is applied to several possible ISDN communications configurations, enabling a number of technical issues to be easily identified.     

ISDN computer-aided telephony

It is argued that ISDN computer-aided telephony requires properly architected platforms to satisfy changing application needs during the 1990s. Proper architecting necessitates the use of functionally rich and consistent telephony application programming interfaces (APIs). Other APIs are also needed to support integrated applications. The coexistence of telephony and other APIs must be accommodated in the ISDN driver architecture to make efficient use of D-channel signaling and voice, data, or image communications on the associated B/H channels. This driver may support Open Systems Interconnection (OSI), Systems Network Architecture (SNA), X.25, or other protocol stacks in the same computer using a single ISDN access link. Applications being currently explored show that significant benefits can be realized using incoming call management and LAN-based image server access by means of ISDN. It is envisioned that by the year 2001, a common API will facilitate multimedia applications on multivendor platforms architected within the OSI framework. These platforms will support interconnections of public and private ISDNs and bridging to BISDNs     

ISDN User-Network Interfaces

This paper provides an overview of the objectives and basic characteristics of the standard ISDN user-network interfaces. These standard interfaces form the basis of many of the essential characteristics of ISDN: terminal portability, the wide range of applications using ISDN, and low cost through high-volume production of standard semiconductor chips. The structure of the interfaces, and the physical applications permitted with the interfaces, are described in some detail. References to sources of more detailed information are provided.     

Research on Advanced Switching Techniques for the Evolution to ISDN and Broadband ISDN

Switching techniques for packetized data and for video communications are a key element in the evolution of the central office from IDN, to ISDN, and to broadband ISDN. An evolutionary scenario, based both on a short-term and on a longterm reference architecture for the switching system, is proposed, and two advanced switching techniques for labeled switching and for diffusive video switching, respectively, are analyzed which match the above scenario well. Plans and preliminary results are also reported on experimental research through laboratory demonstrators of the two switching techniques.