Buffer contents and cell delay in a rate adaptation buffer with Markovian arrivals

Abstract

This paper investigates the performance of a rate adaptation buffer in the case that the arriving cell stream is generated by an on/off-source, where both the on-periods and the off-periods are geometrically distributed. The ratio between the input rate and the output rate takes an arbitrary integer value greater than one. Under the assumption of an infinite storage capacity, exact explicit expressions are obtained for the mean values and the tail distributions of the buffer contents and the cell delay. Furthermore, an approximation is derived for the cell loss ratio in a finite-capacity buffer. Some numerical results are presented and discussed. Scope and purpose In communication networks a rate adaptation buffer is used at the interface between two consecutive links, when the speed of the incoming link exceeds the speed of the outgoing link, in order to avoid excessive loss of information. So far, only few papers in the literature have investigated the buffer dimensioning of a rate adapter. All of these papers assume an uncorrelated arrival process on the incoming link and/or small differences between the input and the output rates, assumptions which in practice may not always be realistic. The present paper therefore presents and analyzes a discrete-time queueing model for a rate adaptation buffer which both accounts for the presence of correlation in the arrival stream and allows (possibly) large input/output ratios.