Performance implications of fluctuating server capacity

In this paper, we consider a variant of an M/M/c/c loss system with fluctuating server capacity. To gain insight into the performance implications of such a stochastic capacity system, we start by analyzing a simple, approximate model. Next, we develop a detailed model using MRGP, such that blocking and dropping metrics can be calculated explicitly from a set of primary inputs, such as arrival rate, service rate, and capacity fluctuation rate. We investigate the functional behaviour of the system, using both the approximate model and the detailed model. The results illustrate some tradeoffs between the blocking rate and the dropping rate, and the sensitivities of these performance metrics to various system parameters. The significance of the results in the context of capacity planning and network performance evaluation is highlighted. (c) 2008 Elsevier B.V. All rights reserved.