Worst Case Traffic from Policed Traffic Sources

Walsh, Cormac

HPL-BRIMS-2001-01

Keyword(s): worst case traffic; leaky bucket; generic cell rate algorithm; effective bandwidth

Abstract: We address the problem of maximising the effective bandwidth of a traffic source over the space of all stationary traffic sources which have realisations meeting certain constraints. Specifically, we ask that the peak rate of the source does not exceed ? and that realisations obey a "leaky bucket" constraint with bucket size β and leak rate σ.We present two results as a step towards a solution. Firstly, we reduce the optimisation over all stationary processes to an optimisation over periodic processes, that is sources which emit traffic in a periodic manner with uniformly distributed phase. Secondly, we show that the realisations of a worst case source must obey the following conditions: at each time, the transmission rate must be one of 0,σ, or ?; the transmission rate may only be σ when the leaky bucket is either empty or full; each burst of activity must either start with the leaky bucket empty or end with it full.

16 Pages

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