Empirical E ective Bandwidths

We analyze the accuracy of four methods for measuring e ective bandwidths (EBs). We also seek to point out advantages and drawbacks of the four estimators. We nd that for nite time realizations of a process the measured e ective bandwidth di ers considerably from its analytical counterpart. We also show that increasing the trace length has little impact on the accuracy of the measurements. We explain this behavior as a consequence of the intrinsic characteristics of the observed trace. We subsequently introduce the notion of \empirical e ective bandwidth" (EEB) as a measure of performance tailored to the actual values. We derive properties of the EEB which capture its behavior in the parameter space and we contrast these properties with the ones obtained for analytical e ective bandwidths. Finally, we comment on the use of EEBs in the context of connection admission