Partially shared buffers with full or mixed priority

This paper studies a finite-sized discrete-time two-class priority queue. Packets of both classes arrive according to a two-class discrete batch Markovian arrival process (2-DBMAP), taking into account the correlated nature of arrivals in heterogeneous telecommunication networks. The model incorporates time and space priority to provide different types of service to each class. One of both classes receives absolute time priority in order to minimize its delay. Space priority is implemented by the partial buffer sharing acceptance policy and can be provided to the class receiving time priority or to the other class. This choice gives rise to two different queueing models and this paper analyses both these models in a unified manner. Furthermore, the buffer finiteness and the use of space priority raise some issues on the order of arrivals in a slot. This paper does not assume that all arrivals from one class enter the queue before those of the other class. Instead, a string representation for sequences of arriving packets and a probability measure on the set of such strings are introduced. This naturally gives rise to the notion of intra-slot space priority. Performance of these queueing systems is then determined using matrix-analytic techniques. The numerical examples explore the range of service differentiation covered by both models

Delay analysis of a discrete-time multiclass slot-bound priority system

This paper introduces a new priority mechanism in discrete-time queueing systems that compromises between rst-come-rst-served (FCFS) and head-of-line (HoL) priority. In this scheduling discipline - which we dubbed slot-bound priority - customers of dierent priority classes entering the system during the same time-slot are served in order of their respective priority class. Customers entering during dierent slots are served on a FCFS basis. In this paper we study the delay in anN-class discrete-time queueing system under slot-bound priority. General independent arrivals and class-specic general service time distributions are assumed. Expressions for the probability generating function of the delay of a random type-jcustomer are derived, from which the respective moments are easily obtained. The tail behaviour of these distributions is analyzed as well, and some numerical examples show the eect slot-bound priority can have on the performance measures

Performance of a partially shared priority buffer with correlated arrivals

In this paper, we analyse a finite sized discrete time priority buffer with two types of packet arrivals, referred to as class 1 and class 2 packets. Packets of both classes arrive according to a discrete batch Markovian arrival process, taking into account the correlated nature of arrival processes in heterogeneous telecommunication networks. Packets of class I are assumed to have both space priority and transmission priority over packets of class 2. In particular, the partial buffer sharing acceptance policy is adopted as space priority mechanism. Using a matrix analytic approach, the buffer content is analysed and through some numerical examples, the impact of the priority scheduling, the threshold and the correlation in the arrival process is demonstrated