The IEEE 802.4 Token Bus--An Introduction and Performance Analysis

Abstract

We present a brief tutorial on the new IEEE 802.4 standard for token bus networks. followed by .a performance analysis based upon simulation studies. We show how total bus capacity is divided among data throughput. token traffic, and propagation delays. We show the relative contributions of access delay and queueing delay to total message delivery time as functions of the network's offered load. The effects of message size and the number of active stations on message delivery times are also investigated. As the token cycle time increases beyond the Target_Rotation_Times for the non~Syrvchronaus acce.s's_classes, service to the lower priority classes is curtailed: we present a formula which can be used to identify the offered load at which the transition (from normal to curtailed service) begins. This paper has been submitted for publication in the IEEE Transactions on Commurtica -tions. Note: Abstract extracted from PDF file via OCR