Performance Analysis of a Fileserver in an ATM Network

Abstract

ATM continues to gain acceptance as a unifying communications technology for traffic of both digital and analog origins. The main characteristic of an ATM network is its discrete time (slotted) operation and fixed-length packets. In this paper we analyze the performance of a fileserver operating in an ATM network to serve files to a group of workstations upon requests of the latters. We assume that the file requests arrive into the file-server as short messages of one packet each. The files themselves are assumed to have a geometrically dis¬tributed number of packets. The requests arriving into the fileserver are buffered in a queue and are treat¬ed on a first come first serve (FCFS) basis. A request is dismissed from the queue only when its associat¬ed file has been fully transmitted to the requesting station. We analyze three metrics for the fileserver: occupancy, unfinished work, and waiting time. For each of these metrics, we obtain the probability generating function (PGF), the entire distribution, and the expec¬tation.