Nested threshold cell discarding for ATM overload control: optimization under cell loss constraints

Overload control in asynchronous transfer mode (ATM) networks is dealt with via priority cell discarding mechanisms governed by a set of nested queue fill thresholds. An efficient search technique is developed which is applicable to any number of discarding priorities for determining the set of thresholds that optimize the offered load when constraints on cell loss (discarding) probabilities are specified. Results are presented as a function of queue capacity for given traffic distribution and arrival statistics. The results indicate that nested threshold discarding systems can support significantly higher traffic loads than systems without priorities. The sensitivity of the performance advantage to traffic mix and cell loss constraints is also illustrated. The efficient search procedure is shown to provide substantial computational gain when there are more than two discarding priorities