Dynamic bandwidth reservation for label switched paths: An on-line predictive approach

Managing the bandwidth allocated to a Label Switched Path in MPLS networks plays a major role for provisioning of Quality of Service and efficient use of resources. In doing so, twomain contrasting factors have to be considered: not only the bandwidth should be adapted to the traffic profile but also the effort for bandwidth renegotiation associated with a variation of the allocated bandwidth should be kept at low levels. In this context, we formulate a problem of optimal LSP bandwidth reservation as the one of minimizing a convex combination of the difference between the assigned bandwidth and the estimated future traffic, and of a measure of the frequency of bandwidth variations. The contribution of this paper is to propose a new method to reserve optimally the bandwidth of an LSP, avoiding an excess of bandwidth renegotiations on the basis of prediction of future traffic, assuming a simple birth-and-death model to describe the traffic dynamics. Whenever the prediction is inaccurate due to unpredictable variations in the characteristics of real traffic, a suitable ‘‘emergency procedure’’ is proposed, which performs a new traffic prediction and a consequent modified bandwidth reservation. Numerical results are presented which show the effectiveness of the method and the achieved performance, both for simulated and real data traffic. 2006 Elsevier B.V. All rights reserved.