The Availability of a Computer System Communications Network as Perceived by a User and Viewed Centrally

Abstract

A communications network has been assessed for availability as perceived by a user of the system and also as seen from the centralised computer. The user view analysis uses a state transition model to demonstrate that high availability is attainable for individual services at remote locations. There is a penalty that might be incurred in achieving this level of service which is revealed in a simulation model of the distribution of availability of the complete system. The second analysis based on the central view of the system confirmed the need for a centrally located operators console to control the interconnection and fault diagnosis of the communications equipment. The paper describes the communications network, gives a summary of the user view analyses and the results of the simulation.