Why are ISDN standards important?

The advantages offered by the integrated services digital network (ISDN) to US Department of Defense (DoD) communications in terms of interoperability provides a framework for a discussion of ISDN standards. The standards organizations working on ISDN and network protocol standards are described, and their relationship to each other is delineated. The status of the standards being developed is discussed, and those that would be of special interest to the US DoD are examined     

VSAT-enhanced ISDN: architectures and implementation

The authors discuss the applications of very small aperture terminals (VSATs) to the ISDN. Typical VSAT network architectures include point-to-point interactive, point-to-multipoint broadcast, and interactive star configurations. VSATs and satellite communications have found new applications for integrated network solutions yielding hybrid network architectures that mix terrestrial and satellite segments. These issues and their implications are examined in the context of ISDN. Six hybrid network configurations are described to address various applications. A proof of concept implementation utilizing a hybrid terrestrial/satellite ISDN network was performed. The demonstration showed the feasibility of using hybrid networks as a backup for terrestrial communications as well as for service extension via satellite. The architecture and implementation of this configuration are described     

Southwestern Bell Telephone's ISDN experience

Southwestern Bell Telephone's (SWBTs) integrated services digital network (ISDN) experience has been heavily influenced by the realization that from a customer perspective, the most important aspects of ISDN are its applications. The authors describe the following ISDN applications that SWBT has been exploring: desktop conferencing; asynchronous protocol conversion to SNA/SDLC; VTAM INN link replacement; asynchronous protocol conversion to SNA/SDLC with multiplexing; remote 3174 multiplexing via B channel packet; remote 3174 multiplexing via B channel packet and NPSI; 327X emulation via SIMPC, SIM-VTAM, and NPSI; 327X emulation with QLLC and NPSI; asynchronous access to private packet-switched networks; asynchronous access to UNIX host; asynchronous access to UNIX host via PAD and X.25 multiplexing; 327X coaxial cable elimination; extended local area network with passive bus; asynchronous access to Ethernet terminal server; dedicated line replacement (64 kb/s); asynchronous modem pooling (out-dial); asynchronous modem pooling (in-dial); ISDN wide-area networking; ISDN data gateway; gateway to AppleTalk network; application processor features; circuit-switched compressed video; and Ethernet LAN bridging     

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     

Working at home [ISDN role]

The benefits of working at home, supported by the integrated services digital network's (ISDN) high-capacity bandwidth and public network ubiquity, are discussed. The business case for telecommuting is presented. The roles of ISDN and the communications industry in promoting telecommuting are described     

ISDN signal distribution network

The author discusses the ISDN Staged Transport System (STS). The STS illustrates how an ISDN network can be used as a flexible distribution medium for directing real-time signals over a WAN to a staged transport server. Although the signal feeds distributed by the STS application are audio voice grade circuits (VGCs), the architecture lends itself to other signal types, such as video. Moreover, ISDN bridges and routers allow the real-time communications infrastructure to distribute bulk recorded signals as well. Finally, the multimedia wide-area connectivity provided by ISDN allows an entire signal processing operation to be remoted, with receivers, storage, and mission control all managed from a single site (or multiple sites) on the network. While the STS application uses the user to user information element (UU-IE) to control signal processing on the edge of the ISDN network, the UU-IE could just as easily be used on the interior of the network by switch adjuncts to augment dialed number routing with intelligent-application-based routing. When combined with the rich set of commercially available applications available on many ISDN switches and adjuncts, sophisticated signal processing, distribution, and management networks could be rapidly configured and deployed with relative ease     

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     

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     

Role of ISDN signaling for a satellite system with on-boardprocessing

The onboard processing (OBP) system, as currently being developed by the European Space Agency, ensures full satellite/ISDN compatibility for worldwide ISDN service operation. The authors present various arguments for opting for the international standard ISDN signaling scheme, propose several alternatives for effective interworking between different applications supported by the OBP system, and address an efficient method to transport DSS1 through the satellite system and to meet CCITT delay performance objectives for end-to-end connections     

Fuzzy generalized network approach for solving an optimization model for routing in B‐ISDN

Routing algorithms are required to guarantee the various quality of service (QoS) characteristics requested by the wide range of applications supported by Broadband Integrated Services Digital Networks (B‐ISDN). In this paper the routing problem is formulated as a fuzzy multiobjective optimization model. The fuzzy approach allows for the inclusion and evaluation of several criteria simultaneously. The proposed model takes into consideration the balancing of the load in the network to avoid link saturation and hence the possibility of congestion. A hybrid approach that combines the generalized network concept with the technique of fuzzy programming is recommended to solve the model. The efficiency and applicability of the model is tested under different load conditions by studying several measures of performance. This revised version was published online in June 2006 with corrections to the Cover Date.     

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     

Technology '89: telecommunications

The demonstration in late 1988 of an experimental broadband ISDN (integrated-services digital network) in Japan, which conforms to the draft international standards recommended by the International Telegraph and Telephone Consultative Committee (CCITT) is discussed. Other 1988 developments discussed are the commercial operation of TAT-8, the first transatlantic fiber-optic cable between the US and UK; wavelength-division multiplexing of up to 10 channels on a single fiber, using tunable semiconductor lasers; the push for digital cellular phones; deregulation in the US of very-low-power radio transmission; and progress in gateways and faxphones     

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     

A signaling protocol for complex multimedia services

The author introduces a signaling protocol for user applications that invokes multimedia services provided by the EXPANSE research prototype, a broadband ISDN testbed. A generic framework that flexibly accommodates a wide variety of services involving multiple parties with heterogeneous terminals is described. The author describes the generic services supported, introduces the EXPANSE call model, discusses syntax and message flow procedures, and relates EXPANSE signaling to the ISDN signaling control part (ISCP) and long-term broadband ISDN signaling work currently under study by CCITT     

Digital subscriber lines: network considerations for ISDN BasicAccess standard

The authors review digital subscriber line (DSL) technology features and the key technical factors that have driven the development of the technology. The application of DSL technology to network access and the relevant standards activities that provide a framework for developing DSL performance requirements are considered. The important aspects of the physical and operational characteristics of the US loop plant that influenced critical technology choices are reviewed with an emphasis on the physical characteristics of the embedded loop plant and considerations pertinent to the economic provisioning and operations for ISDN (integrated services digital network) Basic Access. A review of the essentials of DSL technology for ISDN Basic Access is presented     

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.     

ISDN in North America

The North American ISDN Users' Forum (NIUF), intended to bring together the communities involved in shaping a market-driven competitive ISDN, is discussed. These communities include users, service providers, network equipment manufacturers, customer premises-equipment (CPE) manufacturers, and applications software developers. The role of the NIUF in the product development cycle, NIUF activities, and other important ISDN activities that complement the NIUF work are described. The beginning deployment of a national ISDN and a major demonstration of ISDN capability within North America are also discussed. It is argued that the budding cooperation between the NIUF, the standards bodies, the Corporation for Open Systems (COSs), and Bellcore suggests that migration toward a single set of well-defined specifications is underway     

商用综合业务数字网在中国起步

本文介绍了我国对综合数字网（ＩＳＤＮ）的需求和目前我国实施ＩＳＤＮ的网络装备基础；描述了我国ＩＳＤＮ的实施方案以及ＩＳＤＮ的业务应用。     

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.