Utilizing bandwidth sharing in the slotted ring

This paper is concerned mainly with the stochastic modelling and performance comparison of two of the more common ring networks – token rings and slotted rings. New models for the slotted ring and extensions of existing token ring models are presented. Simulation models are used to validate certain assumptions used in the analytic models. Mean delay time is chosen as the performance index. The effect of various ring parameters on the delay time is studied. These parameters include the network load, the number of active stations on the ring and in the case of the slotted ring, the number of slots and the slot size. For the token ring, the effect on performance due to the service discipline (exhaustive and nonexhaustive) and the mode (single and multiple-token) is also analysed.

The object of research in the article are the tools and capabilities of the C# programming language for the implementation of cybersecurity analysis software in local computer networks and computer-integrated systems. The relevance of the study is due to the importance of information security of computer and computer-integrated systems in government, military-industrial complex, private business etc., and due to the importance of training cybersecurity professionals in higher education to consider teaching examples in popular programming languages. The goal of the work is to research the possibilities of the C# programming language for the development of software that analyzes cybersecurity in local computer networks and computer-integrated systems. The tasks to be solved are: to develop software for scanning network device ports in computer networks and computer-integrated systems for information security audit, using tools and libraries of the C# programming language, to research the benefits and possibilities of using this programming language for this task. Research methods: theory of computer networks, object-oriented programming, theory of algorithms and data structures, theory of software testing. Conclusions. In this paper the possibilities and advantages of the C# programming language for developing cybersecurity analysis software for computer and computer-integrated systems were explored. In the course of work software that analyzes information security in local computer networks and computer-integrated systems was developed. This software can be used for educational purposes in learning the C# programming language and cybersecurity of computer systems. The developed software has the potential to be further improved and applied in various fields to test the cybersecurity of local computer networks and computer-integrated technologies.

The defining characteristic of a networked control system (NCS) is having a feedback loop that passes through a local area computer network. This paper considers nonlinear systems controlled in this manner, and demonstrates that for sufficiently high transmission rates, the network may be considered transparent. Three methods of scheduling data packets are compared: a static scheduler (token ring), the try-once-discard (maximum-error-first) scheduler with continuous priority levels, and the try-once-discard scheduler with discrete priority levels. The third method is of particular interest when only a small number of bits are available for collision resolution. Asymptotic stability is guaranteed in the first two cases, and ultimate uniform boundedness in the third. In the final section, simulations demonstrate the theoretical results. The contributions of this paper are two-fold: first, it extends the earlier results on NCS to nonlinear systems, and second, it allows for finite word-length message identifiers.

Models for local area networks of the slotted ring style of architecture are developed and evaluated. The hardware protocol is modeled using a BCMP network. The Basic Block protocol of the Cambridge ring is modeled using an approximate solution method of the fixed-point type. A limited comparison between the Cambridge Ring and another ring architecture—the token ring—is carried out.

Introduction The Problem Statement Today's desktop video is an emerging technology. Business, industrial, and educational systems can all benefit from presenting video images to many users simultaneously. Video transmission consumes a great deal of network resources. A simple calculation shows (Goldman, J., 1995) that uncompressed full-screen motion video requires more than 80-megabits/second bandwidth. The majority of local area networks (LAN), which have the transmission speed of 10-16 megabits/second, cannot carry such traffic. New developments (Fast Ethernet, 100VG-AnyLAN) are not yet widespread. Although they can improve the performance of video distribution, uncompressed video traffic is unacceptable even for these networks. The main directions in reducing bandwidth requirements are: * employing various video compression techniques. By using an appropriate compression technique, the transmission of a high resolution compressed video may require 6-24 megabits/second bandwidth; * reducing the amount of video data, which has to be transmitted. It can be done by reducing the number of pixels per line, lines per frame, and frames per second. Of course, this reduction may be done at the expense of video frame resolution and full motion video quality. As an example, we can mention the CCITT's ( International Telegraph and Telephone Consultive Committee (now ITU-T) H.261 video transmission standard. It defines two different video resolution formats: Common Interface Format with 352 pixels by 288 lines per frame and Quarter Common Interface Format with 176 pixels by 144 lines per frame. The delay-sensitive nature of video information introduces another problem of video transmission. Ethernet, Token Ring, and FDDI networks allow delays in transmission of video data. One of the ways of solving this problem is employing such services as frame relay and ATM which are not widely used yet. Any video transmission in a local area network must coexist with other network activities. A huge amount of data involved in a video transmission slows down all other local area network operations. That can be very frustrating for users who are not involved in the current video session. In a real-time system the situation may even become dangerous because of delays in emergency information. Unfortunately, none of the above mentioned strategies can solve all the problems of video distribution. All of them have their own benefits and drawbacks. In this paper we consider one possible way of solving the problem of video distribution. We examine a Hybrid Analog/ Digital Video Network (ADViNet) which uses two parallel communication media: analog - for transmitting video images, digital - for data transmission. We present the model and architecture of a video network and ADViNet protocol. We also analyze the benefits and weaknesses of the video networks. Background The typical physical architecture of a Hybrid Analog Digital Video Network (ADViNet) includes two communication media: digital and analog. The digital medium is used by a regular digital network according to its type and topology. The analog medium combines a VGA bus with several additional control lines. All the monitors in the LAN are connected to this bus by special switches. Each monitor can work in one of the two states: local--when the user can work independently with his/her workstation; and remote--when the monitor is connected to a remote source of video information. The analog bus is controlled centrally from the control panel located near the master station. We have implemented ADViNet in a classroom/laboratory at the College of Staten Island. On the physical level in our video network environment we use a Computer Video Web (ComWeb). ComWeb is a commercially available pure hardware system for video distribution (Computer Video Web, 1996). The analog transmission medium has a centralized manual control on the physical level at the control panel connected to the main hub or control can be programmed from the central station. …

It is argued that over the next 15 years, there should be a quantum increase in the amount of computing power delivered to the user. This paper will be derived from the network to which these devices are connected. While all of this will be of interest to the technologist, there is no focus being given to the application of the power of the local computer network (LCN) to the needs of the users. The LCN is then examined from the viewpoint of what is necessary if the LCN in particular, and computing in general, is to achieve its full capability as a tool for users. >

GAMMA-NET: A local computer network coupled by a high speed optical fiber ring bus — system concept and structure

37th Annual IEEE Conference on Local Computer Networks - Workshops

Local area computer network simulations are inherently non-Markovian in that the underlying stochastic process cannot be modeled as a Markov chain with countable state space. We restrict attention to local network simulations whose underlying stochastic process can be represented as a generalized semi-Markov process (GSMP). Using new better than used distributional assumptions and sample path properties of the GSMP, we provide a geometric trials criterion for recurrence in this setting. We also provide conditions which ensure that a GSMP is a regenerative process and that the expected time between regeneration points is finite. Steady-state estimation procedures for ring and bus network simulations follow from these results.

The role of a robot is to save money and manpower in the real world. When the robot accomplishes this role to realize an autonomous function, unification of the system is a central issue. Hence, it is a subject to construct the control architecture as an unified method of intelligent control. Some research works about the error recovery ststem are carried out on manipulators, manufacturing systems, computer networks and so on. However, the hierarchical error recovery system has not been studied so much for autonomous mobile robots. In this paper, we propose a hierarchical control architecture HALAS (Hierarchical Adaptive and Learning Architecture System) as a control architecture for an autonomous mobile robot. The main feature of HALAS is the hierarchical error recovery function. We applied HALAS to an air conditioning equipment inspection robot. The validity of the proposed system is shown through some experimental results.

This paper investigates the solution of the optimization problem that appears in the design of double loop structured local area computer networks or interconnection networks. Double loop structure is a regular, two-connected network, designed for packet communications. The studies of degree two network connection schemes is based on the circular graphs of degree four. These graphs are regular, vertex-symmetric, and maximally connected, and such optimal graph exists for any given number of nodes. Every four of two-connected nodes consists a cluster, so cluster is a component with four input and four output link in the network. The proposed cluster network forms the optimal connection of a circular graph. We demonstrate how to construct one such network for any number of nodes and examine their network properties. The problem of routing is also addressed, and two routing rules are investigated that take advantage of the network regular structure.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The use of multiple buses can improve both the fault tolerance and performance of local area computer networks. Existing schemes either depend on active components for full connectivity or can experience decreased performance as many hosts attempt to access one bus. An architecture class based on balanced incomplete block designs (BIBDs) is proposed to address these problems. A BIBD architecture uses redundant communication channels and exhibits degradable performance as faults occur. The performability of such networks is evaluated, where evaluation is based on stochastic activity network models. The results obtained are provided for comparison of BIBD network performability with that of conventional multibus networks. >

The textbook outlines the main directions in the development of modern information technologies and the principles underlying them. The book consists of five sections devoted to technical means of information technology, software, features of creation and transformation of information objects and technologies of construction of local and global computer networks. Meets the requirements of the federal state educational standards of secondary vocational education of the latest generation. It can be used both in the system of secondary vocational education and in educational institutions of higher professional education.

Local area computer networks for industrial process control: Mataix, J and de la Puente, J AMundo Electronico No 163 (June 1986) pp 57–63 (in Spanish)

This discussion considers in particular the application of ISDN technology to data processing needs, and gives some practical examples showing when an ISDN implementation in an organisation can be feasible. >