A time-scale decomposition approach to measurement-based admission control

We propose a time-scale decomposition approach to measurement-based admission control (MBAC). We identify a critical time scale, T˜_h, such that: 1) aggregate traffic fluctuations slower than T˜_h can be tracked by the admission controller and compensated for by flow admissions and departures; 2) fluctuations faster than T˜_h have to be absorbed by reserving spare bandwidth on the link. The critical time scale is shown to scale as T_h/√n, where T_h is the average flow duration and n is the size of the link in terms of the number of flows it can carry. An MBAC design is presented which filters aggregate measurements into low- and high-frequency components separated at the cutoff frequency, 1/T˜_h, using the low-frequency component to track slow time-scale traffic fluctuations and the high-frequency component to estimate the spare bandwidth needed. Our analysis shows that the scheme achieves high utilization and is robust to traffic heterogeneity, multiple time-scale fluctuations and measurement errors. The scheme uses only measurements of aggregate bandwidth and does not need to keep track of per-flow information.