Analysis and Tuning of the Fddi Media Access Control Protocol

Abstract

FDDI provides a 100 Mbit/s communication system to interconnect computer and peripheral equipment using fiber optics as the transmission medium in a ring configuration. The FDDI MAC priority mechanism supports two classes of traffic: synchronous and asynchronous. The asynchronous class makes provision for up to eight different priority levels. The protocol has several parameters set to control the relative performance (throughput and delay) of the asynchronous priority levels. In this paper, we focus on the relationship between the FDDI MAC parameter settings, the ring configuration, and the performance of the asynchronous priority levels. A procedure to calculate estimates for the throughput of each asynchronous priority level over a range of frame arrival rates is developed. Using this procedure, performance results are presented to demonstrate characteristics of the FDDI priority mechanism. We also describe a procedure that can be used to tune the FDDI parameters so that given performance objectives for the various priority levels are achieved. Such a procedure is a useful tool for configuring and managing an FDDI network. © 1988 IEEE