Place reservation: Delay analysis of a novel scheduling mechanism

We study the delay performance of a queue with a place reservation mechanism. The objective of this discipline is to provide a better quality of service to arriving packets that are delay sensitive at the cost of allowing higher delays for the best effort packets and was first proposed by Burakowski and Tarasiuk. In our model, we consider a discrete-time queue with arrivals of type 1 (delay sensitive) and type 2 (best-effort). Whenever a packet of type 1 enters the queue, it takes the position of the reservation that was created there by a previous arrival of type 1 and creates a new reservation at the end of the queue. Type 2 arrivals always take place at the end of the queue in the usual way. We present the analysis of this model based on the use of generating functions and provide results for the mean value, variance and tail behaviour of the delay experienced by both the delay-sensitive and the best-effort traffic. For a specific example, we compare the delay performance of this reservation discipline to the performance of an absolute priority discipline on the one hand, and to the reference discipline first-in first-out on the other.