How the Bernoulli slot occupancy approximation in the node DQDB analytical model influences the throughput-delay performance

The effect of the Bernoulli slot occupancy approximation, which is assumed in most distributed queue dual bus (DQDB) analytical models, on the throughput-delay characteristics of DQDB networks is studied. Studies cover a variety of traffic statistics and network configurations. The results reveal that the influences of the Bernoulli slot occupancy approximation are message length, internode distance, and carried network load dependent. In general, for light to medium carried network load and relatively short message length, the analytical model tends to underestimate the mean message delay. The shorter the internode distance is, the smaller are the network load and message length values at which the analytical model starts to overestimate the mean message delay.