ANALYSIS OF STOCHASTIC FLUID QUEUES DRIVEN BY LOCAL-TIME PROCESSES

We consider a stochastic fluid queue served by a constant rate server and driven by a process which is the local time of a reflected Levy process. Such a stochastic system can be used as a model in a priority service system, especially when the time scales involved are fast. The input (local time) in our model is typically (but not necessarily) singular with respect to the Lebesgue measure, a situation which, in view of the nonsmooth or bursty nature of several types of Internet traffic, is nowadays quite realistic. We first discuss how to rigorously construct the (necessarily) unique stationary version of the system under some natural stability conditions. We then consider the distribution of performance steady-state characteristics, namely, the buffer content, the idle period, and the busy period. These derivations are much based on the fact that the inverse of the local time of a Markov process is a Levy process (a subordinator), hence making the theory of Levy processes applicable. Another important ingredient in our approach is the use of Palm calculus for stationary random point processes and measures.