Multimedia Teleservices Modelled with the OSI Application Layer Structure

This paper looks into the communications capabilities that are required by distributed multimedia applications to achieve relation preserving information exchange. These capabilities are derived by analyzing the notion of information exchange and are embodied in communications functionalities. To emphasize the importance of the users' view, a top-down approach is applied. The (revised) OSI Application Layer Structure (OSI-ALS) is used to model the communications functionalities and to develop an architecture for composition of multimedia services with these functionalities. This work may therefore be considered an exercise to evaluate the suitability of OSI-ALS for composition of multimedia teleservices

The Dutch interbank computer network

At the end of 1980, a strategic decision was made by the Dutch banks and savings banks to commence the development of a Data Communications Infrastructure (DCI), to be used for a number of forthcoming interbank applications. It was agreed that this new data communications infrastructure should be based on the emerging Reference Model for Open Systems Interconnection (OSI). The first interbank application using the DCI (i.e. urgent money transfers) was introduced in the second quarter of 1985. Other interbank applications, which will also make use of the functions provided by the DCI, are currently being developed.\ud \ud This paper provides the background to the DCI project, discusses the selection of OSI standards for the network, and gives an overview of the design of the software package, which was developed to support the selected OSI standards

A critical analysis of the X.400 model of message handling systems

The CCITT X.400 model of store and forward Message Handling Systems (MHS) serves as a common basis for the definition of electronic mail services and protocols both within CCITT and ISO. This paper presents an analysis of this model and its related recommendations from two perspectives. First the concepts of service, protocol and interface are discussed together with their application to this model; second the positioning within ISO's reference model for Open Systems Interconnection (OSI) is commented on

Introduction to the ISO specification language LOTOS

LOTOS is a specification language that has been specifically developed for the formal description of the OSI (Open Systems Interconnection) architecture, although it is applicable to distributed, concurrent systems in general. In LOTOS a system is seen as a set of processes which interact and exchange data with each other and with their environment. LOTOS is expected to become an ISO international standard by 1988

Computing infrastructure issues in distributed communications systems : a survey of operating system transport system architectures

The performance of distributed applications (such as file transfer, remote login, tele-conferencing, full-motion video, and scientific visualization) is influenced by several factors that interact in complex ways. In particular, application performance is significantly affected both by communication infrastructure factors and computing infrastructure factors. Several communication infrastructure factors include channel speed, bit-error rate, and congestion at intermediate switching nodes. Computing infrastructure factors include (among other things) both protocol processing activities (such as connection management, flow control, error detection, and retransmission) and general operating system factors (such as memory latency, CPU speed, interrupt and context switching overhead, process architecture, and message buffering). Due to a several orders of magnitude increase in network channel speed and an increase in application diversity, performance bottlenecks are shifting from the network factors to the transport system factors.This paper defines an abstraction called an "Operating System Transport System Architecture" (OSTSA) that is used to classify the major components and services in the computing infrastructure. End-to-end network protocols such as TCP, TP4, VMTP, XTP, and Delta-t typically run on general-purpose computers, where they utilize various operating system resources such as processors, virtual memory, and network controllers. The OSTSA provides services that integrate these resources to support distributed applications running on local and wide area networks.A taxonomy is presented to evaluate OSTSAs in terms of their support for protocol processing activities. We use this taxonomy to compare and contrast five general-purpose commercial and experimental operating systems including System V UNIX, BSD UNIX, the x-kernel, Choices, and Xinu

Performance analysis of CCSDS path service

A communications service, called Path Service, is currently being developed by the Consultative Committee for Space Data Systems (CCSDS) to provide a mechanism for the efficient transmission of telemetry data from space to ground for complex space missions of the future. This is an important service, due to the large volumes of telemetry data that will be generated during these missions. A preliminary analysis of performance of Path Service is presented with respect to protocol-processing requirements and channel utilization

A methodical approach to performance measurement experiments : measure and measurement specification

This report describes a methodical approach to performance measurement experiments. This approach gives a blueprint for the whole trajectory from the notion of performance measures and how to define them via planning, instrumentation and execution of the experiments to interpretation of the results. The first stage of the approach, Measurement Initialisation, has been worked out completely. It is shown that a well-defined system description allows a procedural approach to defining performance measures and to identifying parameters that might affect it. For the second stage of the approach, Measurement Planning, concepts are defined that enable a clear experiment description or specification. It is highlighted what actually is being measured when executing an experiment. A brief example that illustrates the value of the method and a comparison with an existing method - that of Jain - complete this report