Multivariate rate-based overload control for multimedia communications traffic over hybrid switch fabrics

We propose rate-based overload control algorithms for multimedia communications over hybrid switch fabrics, where the load control algorithms are based on two parameters, the call setup delay and the call blocking probabilities. The total number of calls that will be allowed to the system in the next time period is initially calculated by using the call setup delay. The threshold of the call setup delay is based on the target data rate. Afterwards, the total number of accepted calls are distributed accordingly among the switch fabrics using the call blocking probabilities of each fabric. The system consists of a main call processor and various switch fabrics, such as circuit-switching, ATM switching, etc. The algorithms are derived for two switch-fabric case, but they can easily be generalized for multi-switch-fabric cases. The smoothing procedure and overload control probabilities are also introduced to enhance the performance of the system. We observe that the smoothing procedure gives better results in the range of lower offered load. The overload control probabilities enhance the performance in the higher offered load range