AbstractThis paper presents some of the basic concepts and techniques for the modelling of data networks and the determination of performance measures.A simple example of data traffic flow and the service time are investigated first. Then the average message delay traversing the network is decomposed into average message delays on the individual links between node-pairs.It is shown that each link and the associated node-pair in the network can be modeled by a single-server queue. Applications of several singleserver queues to the performance analysis of data networks are also discussed. A simple example and simulation results are presented for illustration.