|
Abstract : |
Bandwidth allocation is a fundamental problem in the design of networks where bandwidth has to be reserved for connections in advance. The problem is intensified when the requested bandwidth exceeds the capacity and not all requests can be served. Furthermore, acceptance/rejection decisions regarding connections have to be made on-line, without knowledge of future requests. We show that the ability to preempt (i.e., abort) connections while in service in order to be able to schedule "more valuable " connections substantially improves the overall throughput of some networks. We present bandwidth allocation strategies that use preemption and show that they achieve constant competitiveness with respect to the throughput, given that any single call occupies only a constant fraction of the bandwidth. Our results should be contrasted with recent works showing that non-preemptive strategies have at most logarithmic competitiveness. An extended summary of this work appears in the proceedings of the 27th STOC, 1995. y, |
