A Time - Scale Decomposition Approach toMeasurement - Based Admission

We propose a timescale decomposition approach to measurement-based admission control (MBAC). We identify a critical timescale f T h such that: 1) aggregate traac uctuation slower than f T h can be tracked by the admission controller and compensated for by ow admissions and departures; 2) uctuations faster than f T h have to be absorbed by reserving spare bandwidth on the link. The critical timescale is shown to scale as T h = p n, where T h is the average ow duration and n is the size of the link in terms of number of ows it can carry. A MBAC design is presented which lters aggregate measurements into low and high frequency components separated at the cutoo frequency 1= f T h , using the low frequency component to track slow timescale traac uctuations and the high frequency component to estimate the spare bandwidth needed. Our analysis shows that the scheme achieves high utilization and is robust to traac heterogeneity, multiple timescale uctuations and measurement errors. The scheme uses only measurements of aggregate bandwidth and does not need to keep track of per-ow information.