A tight upper bound for heterogeneous on-off sources

On-off traffic source models are extensively used in connection admission control (CAC) schemes because of their simplicity and their ability to model real traffic sources. However, the calculation of the probability mass function of heterogeneous on-off sources entails a convolution operation which cannot be carried out in real time. Based on a bufferless fluid flow model this paper proposes the cell loss rate function (CLRF) and uses it for studying cell loss in bufferless systems. The properties of heterogeneous on-off sources in bufferless systems are extensively discussed using CLRF. A tight cell loss upper bound for heterogeneous on-off sources is proposed which results in great computational savings. The upper bound is applied in the CAC scheme. Simulation studies are presented which indicate that the upper bound is tight and the CAC scheme has a very good performance.