An Optimal Randomized Online Algorithm for QoS Buffer Management

Abstract

The QoS (Quality of Service) buffer management problem, with significant and diverse computer applications, e.g., in online cloud resource allocation problems, is a classic online admission control problem in the presence of resource constraints. In its basic setting, packets with different values according to their QoS requirements, arrive in online fashion to a switching node with limited buffer size. Then, the switch needs to make an immediate decision to either admit or reject the incoming packet based on the value of the packet and its buffer availability. The objective is to maximize the cumulative profit of the admitted packets, while respecting the buffer constraint. Even though the QoS buffer management problem was proposed more than a decade ago, no optimal online solution has been proposed in the literature. This paper contributes to this problem by proposing: 1) A fixed threshold-based online algorithm with smaller competitive ratio than the existing results; 2) an optimal deterministic online algorithm under fractional admission model in which a packet could be admitted partially; and 3) an optimal randomized online algorithm for the general problem. We consider the last result being the main contribution of this paper.