Non stationary request distribution in video on demand networks

Several works have recently appeared in the literature on the design, performance and dimensioning of networks supporting video on demand and multimedia services. It has been shown that performance is strongly dependent on the model adopted to describe the user's behaviour in terms of requests for programs. In this paper we provide a detailed investigation of a non stationary model for the user's request distribution. Numerical results are provided for a network scenario proposed in the literature to investigate the error achieved when the non stationary distribution is approximated with a stationary exponential one.