Showing papers on "Network traffic simulation published in 1982"

A Measurement Center for the NBS Local Area Computer Network

Abstract: This paper describes a measurement center for the NBSNET, a distributed, broadcast local area computer network (LAN) at the National Bureau of Standards. A LAN measurement center allows careful testing and evaluation of a network under normal and varying user-defined conditions. The measurement center consists of three components: an artificial traffic generator, a monitoring system, and data analysis software. The traffic generator emulates varied loads on the network, allowing for controlled experimentation and functional testing. The monitoring system captures measurement information about both artificial and normal network traffic. Analysis software summarizes this information into ten measurement reports following each monitoring period. Implementation issues and problems are discussed.

The design of a multi-microprocessor based simulation computer - III

Abstract: This paper presents further results in development of a discrete event simulation computer based on a network of micro processors. The network is being designed by identifying simulation tasks which may be performed in parallel with other computation required by the simulation, and then assigning those subtasks to attached processing elements in the network. The tasks of priority queue processing and state accounting are considered in this paper. A three attached processor simulation computer has been designed, using two processors for the event set and the third for state statistics accumulation. In a simulation model of this system, a forty to fifty percent reduction in the execution of a benchmark simulation program is easily achieved. (The benchmark program itself uses an adaptive scheduling algorithm). Further observations and suggestions for future research are presented.

A network simulation for budgeting

Abstract: One problem with budgeting is the deterministic nature of the tool, even for flexible budgets, that is being used to provide forecasts of a stochastic process. Budget simulation provides not only expected values but anticipated dispersion of budget data as well. The network model may provide the best framework for such a simulation.

City traffic simulation package and its utilization

Abstract: Population explosion in larger cities and increase in vehicle density cause traffic problems in these areas. Intersections are the places where traffic is mostly blocked and most of the accidents occur. Signalization lights at the intersections aim to arrange the traffic flow and to avoid accidents. If not located properly or have bad timing, not only they fail to avoid accidents but also they cause disobeying, time loss and wearyness.Traffic assignment and management deal with those problems to minimize personal and social cost. The results of some mathematical models are applied. It is not easy to predict the cost of any decisions reached about traffic assignment and management, yet, using simulation, those decisions can be tested on a model representing the traffic network and the results thus can be seen before implementation.This study introduces a special purpose simulation program package developed for urban traffic network. The input of the package is data on roads, intersections, signalization lights, stops, traffic load and objective function parameters. Required changes to test differing management decisions can be made easily through keywords supplied and simulation may be repeated. A powerful user language designed and developed for use in data input, operation, and output is also an integral part of the package. Waiting times of vehicles, time and distance of trip, average speed, queue lengths and other statistical results are the output of the package. Such results can also be utilised automatically in evaluating a cost function declared by user in order to test various traffic management decisions.

The design and calibration of a simulation model of a star computer network

Abstract: A simulation model of the CERN (European Organization for Nuclear Research) SPS star computer network is described. The model concentrates on simulating the message handling computer, through which all messages in the network pass. The paper describes the main features of the model, the transfer time parameters in the model and how performance measurements were used to assist in the calibration of the model.

Network performance reporting

Abstract: Managing networks using Network Administration Centers is increasingly considered. After introducing the information demand for operational, tactical and strategic network management the paper is dealing with the investigation of the applicability of tools and techniques for these areas. Network monitors and software problem determination tools are investigated in greater detail. Also implementation details for a multihost-multinode network including software and hardware tools combined by SAS are discussed.

Simulation of Traffic at a T-Intersection Using Slam

Abstract: The flow of traffic at an intersection is often controlled by a traffic signal. This research report models a T-intersection with a disjoint network for each direction of traffic flow, eastbound, westbound and southbound. The traffic signal is modeled with a fourth network. Three types of signal control (pretimed, semiactuated and full-actuated) are modeled to examine the effect of each type on the average delay time and average length of queues for each lane of traffic queue at the intersection. The computer models presented in this report use SLAM computer language to simulate the traffic signal and vehicle flow.

Extraordinary traffic handling in the telecommunication network

Abstract: Extraordinary traffic phenomena caused by network failures, disasters and social accidents cause remarkable deterioration of the network throughput and service grade. Algorithms of traffic control, e.g., originating traffic control, code blocking control, alterante route control and time-out control, have been investigated and some of them have been implemented as countermeasures. This paper studies analytically the mechanism of congestion and traffic handling behavior of the telecommunication network for focused extraordinary traffic overload in a two-stage hierarchical network, using an exchange model which has limited call handling capacity. The congestion at every part of the network can be explained by several factors: network configuration; traffic flow pattern of the extraordinary overload; maximum call handling capacity of exchanges; and the number of channels of the links. The increase of repeated calls arising as the result of congestion at exchanges is one of the dominant factors reducing the throughput of the network.