Session Delay in File Server Output Buffers with General Session Lengths

Abstract

Abstract-In this paper, we analyze the delay incurred by session-based traffic in the output buffer of a file server.Users can start and end sessions during which they are active and download information from the file server. Per time slot, each active user downloads a random but strictly positive number of information packets. Each session lasts for a random, yet again, strictly positive number of slots.We model the file server output buffer as a discrete-time infinite-capacity queueing system and we present an analytical technique to study the queueing delay for sessions in case of a general session-length distribution. The analysis method is based on the combination of a generating-functions approach with the use of an infinite-dimensional state description. As a result, a closed-form expression for the mean session delay is obtained. The analysis is illustrated with a numerical example, based on real traces of file server traffic.

The mean queue content of discrete-time queues with zero-regenerative arrivals

“…Arrival models of interest include, amongst others, finite-state-space Markovian arrival models like the discrete batch Markovian arrival model [1] as well as Markovian arrival models with an infinite but structured state-space. Prime examples of the latter class include M/G/∞-input -often referred to as train arrival or session models, see [3,5,13] -as well as autoregressive arrival models [7,8,10]. Most often, performance analysis of queues with finite-state-space Markovian arrivals relies on a computational approach: efficient algorithms are devised to calculate the performance measures of interest [4].…”