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.     

Unified alignment of isdn-relevant information communications services/applications through a cubic framework

A cubic (three-dimensional) framework is proposed for mapping various information communications services. The framework implies the important aspect of information technology (IT), or C&C (integration of computers and communications) technology as follows. The first axis is based upon the service classification made for BISDN-relevant services by the CCITT. This ‘communications’ axis covers not only the simple communication, or ‘space-wise information transfer’, but also messaging, retrieval etc. as ‘the combined space/time-wise information transfer’. The second axis represents ‘the multiplicity of media use’ in the human interface of information handling systems. The third axis represents the extent of ‘information processing/conversion’ or the level of computer technology penetration. In the latter part of this paper, the important interrelations between computer communications services and ISDN deployment are discussed using the scope of the above-proposed cubic map. The penetration of PMI (personal machine intelligence) to the same level as telephone set and television set, and the corresponding computer communications services requirements are identified as a fundamental driving force of (N)ISDN deployment.     

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.     

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     

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.     

微型通用串行总线的研究动态和应用及传输模型

微型通用串行总线(Micro-USB)作为PC机及各类数码产品的主流接口,因其具有携带方便、传输速度快、易于扩展、总线供电等优点,尤其是其特殊的传输线模型,使其在通用计算机、嵌入式系统为主要应用领域的各种数字系统和设备中得到了广泛的应用,并获得制造商及用户的高度认可,具有广阔的发展前景.     

Multimedia processors

This paper describes large-scale-integration programmable processors designed for multimedia processing such as real-time compression and decompression of audio and video as well as the generation of computer graphics. As the target of these processors is to handle audio and video in real time, the processing capability must be increased tenfold compared to that of conventional microprocessors, which were designed to handle mainly texts, figures, tables, and photographs. To clarify the advantages of a high-speed multimedia processing capability, we define these chips as multimedia processors. General-purpose microprocessors for workstations and personal computers (PCs) use special built-in hardware for multimedia processing, so the multimedia processors described include these modified general-purpose microprocessors. After reviewing the history of programmable processors, we classify multimedia processors into five categories depending on their basic architecture. The categories are reduced instruction set computer (RISC) microprocessors for workstations, complex instruction set computer microprocessors for PCs, embedded RISCs, low-power digital signal processors (DSPs), which are mainly used for mobile communications devices, and media processors that support PCs for multimedia applications. These five classes are then grouped into two: microprocessors with a multimedia instruction set and highly parallel DSPs. An architectural comparison between these two groups on the basis of Moving Picture Experts Group decoding applications is made, and the advantages and disadvantages of each class are clarified. Future processors, including “system on a chip,” and their applications are also discussed     

Computers [1999 technology forecast and analysis]

This paper presents a computer technology analysis and forecast for 1999. The subjects covered include personal computers, magnetic disk storage, open operating systems, digital versatile disks and supercomputers     

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.     

Intelsat planning and modelling software in support of IDR

In order to plan for and integrate intermediate data rate (IDR) carriers into the INTELSAT newtork, while achieving quality service with efficient use of resources, operational planning tools and transmission system models are necessary. These computer software tools and models, which have evolved and grown in parallel with the INTELSAT network, comprise numerous applications on various types of computers, including mainframe, mini and personal computer systems. This paper presents an overview of the major planning and modelling software models used at INTELSAT in support of the use of IDR digital carriers within the INTELSAT system.     

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     

Adaptive logic circuits for digital stochastic computers

A theoretical and experimental investigation of adaptive logic elements suitable for use as an output interface for digital stochastic computers is presented. An adaptive digital element using a binary rate multiplier is demonstrated to provide a significant improvement in accuracy without reduction in bandwidth characteristics.     

Compromising Electromagnetic Emanations of USB Mass Storage Devices

Universal Serial Bus (USB) has become the dominant Plug & Play interface for personal computers and continues to grow. Any digital communication source emits secondary or unwanted emissions, called compromising emanations, as they can be received and used to reconstruct the original transmitted information, thereby compromising the transmitted messages. This paper presents a number of experimental results regarding the USB communication between a personal computer and a USB memory device (USB bulk transfer) that has been performed in a specialized laboratory, and illustrates the capability of restoring information transmitted at bit level only from receiving the compromising radiation emitted by this communications bus. Comparative results for a shielded and unshielded device will also be illustrated. Finally, some TEMPEST protection methods are identified and presented against leakage of information through the compromising radiation of USB communication.

     

Magnetooptics: A thermomagnetic recording technology

Erasable magnetooptic (MO) recording is viewed as a possible successor to electromagnetic recording that is used today in high-performance disk drives for mainframe computers, hard disks, and floppy disks for personal computers and magnetic tape drives. A large number of rare earth-transition metal alloys have been investigated for use as the magnetic recording material. The properties of the films are very sensitive to the film deposition processing parameters. Accelerated life tests show that there are magnetooptic materials that do have all of the necessary properties and stability for use in computer digital storage.     

Personal Computer Communications Via Telephone Facilities

Communication from terminals to other terminals and to computing service systems has been an important aspect of data communications since the early 1960's. When personal computers arrived on the scene, in the 1970's, the use of telephone facilities and modems for communications was a natural extension of existing technology. Now, however, many modems have "intelligence" and can be controlled from their electrical interface, communication software is available to facilitate the use of a modem and coordinate the communication process, and there are many uses for personal computer communications. Some of the hardware, software, and computing services for personal computer communications are discussed in this paper.     

The ISDN U interface and transceiver

This paper describes the integrated services digital network (ISDN) basic rate interface (BRI) two-wire U interface and the transceiver necessary for the digital transmission of 160 kb/s of information over unshielded twisted pair transmission media. Topics discussed include the U interface structure and framing as described in the American National Standards Institute (ANSI) T1.601 specification, and the VLSI implementation of the ISDN U transceiver. Pertinent transceiver design issues addressed include the type of line code used, such as 2B1Q or 4B3T, echo cancellation, near end crosstalk, equalization and sampling rates.     

Simulation of ADSL over ISDN on German subscriber lines

The shortcomings of the existing asymmetric digital subscriber line (ADSL) standard ANSI T1.413 for application with the integrated services digital network (ISDN) are explained. An ADSL system modified by increasing the high-pass cutoff frequency of the splitter to about 140 kHz and, therefore, moving also the pilots, has been simulated under noise conditions and the ISDN requirements of the German subscriber line network. The reach reduction due to ISDN compared with the “plain old telephone service” (POTS) application is shown to he between 10% and 15%. It is proposed to apply ISDN ADSL rather than POTS ADSL     

Technology '88: personal computers

The state of the personal computer field in 1987, in the wake of IBM's introduction of a completely new line of personal computers, known as the Personal System/2, is examined. The possibility that the formerly monolithic IBM PC standard might develop along several different paths is discussed. Other developments, including an open-architecture Apple Macintosh model, are described. An expert opinion is offered by Allen L. Hankinson, chief of the systems and software technology division of the Institute for Computer Sciences and Technology at the National Bureau of Standards, who contends that personal computers now resemble workstations