Satisfying customer bandwidth demand in IP data networks

We introduce the notion of customer access fulfillment in IP data networks and provide a quantitative characterization of the fulfillment using measurements of the router uplink (link connecting a router to the backbone) utilization. The threshold for the uplink utilization is calculated for a given probability of customer fulfillment based on the normal approximation. We use three different stochastic models to prove the normal approximation for the distribution of the uplink utilization. The convergence to the Gaussian diffusion process is proved in the framework of the nonstationary exponential Beneš buffer model. In a special case of an alternating renewal process, we show that the fulfillment can be evaluated based on measurements of the mean uplink utilization. We also prove that the distribution of utilized uplink capacity is asymptotically normal in the context of large generalized Erlang and Engset models. We analyze 5 min measurements of router uplink utilization and show that their empirical distribution is close to normal.