Effective bandwidths of departure processes from queues with time varying capacities

In this paper, we consider a queue with a time varying capacity and identify the effective bandwidth of the stationary departure process from such a queue. Two important observations are made: (i) the effective bandwidths for the transient departure process and the stationary departure process from such a queue are in general different, and (ii) sometimes it is necessary to build up the queue first in order to have a large excursion of the stationary departure process. The new result on the effective bandwidth of the stationary departure process is applied to intree networks with time varying capacities and priority tandem queues. Algorithms for approximating the tail distributions of queue lengths in such networks are derived.