A Numerical Analysis of the M/D b /N Queueing System

In this paper, we provide a numerical analysis of the M=D b =N \Gamma 1 queueing system. This system consists of an infinite buffer and N identical batch servers with batch capacity b. It serves as a model for various types of workstations in the manufacturing context. Using an approach presented by Crommelin, we derive the distribution of the number of lots waiting in queue at arbitrary time instants and the distribution of the waiting time of lots. The results are of an exact nature and the computation is of low complexity concerning run time and memory usage. 1 Introduction Batch servers or bulk servers can be found in many areas of manufacturing. For example, in the manufacturing of semiconductors, lots of wafers are usually grouped together into batches at workstations like oxidation ovens or chemical deposition [1]. Furthermore, identical servers are commonly grouped together as workstations. All servers at a workstation are fed by a single queue. In this way, the idle times o..

Models of WWW-traffic: a comparison of pareto and logarithmic histogram models

In this paper we present results from measurements of WWW-traffic, the analysis of the data measured, and derive two simple models that could be used to describe WWW-traffic for performance assessment purposes. We analyze client WWW-sessions that are characterized by the size of the response and inter-response intervals. The samples of both categories are found to exhibit heavy-tailed properties. Thus, we represent WWW-traffic by two models: an independent Pareto model and a logarithmic histogram model. The models are evaluated by simulating the transmission of traffic generated by the models over an ATM link using the VBR service category. We show that the histogram model is able to represent the properties of WWW-traffic with higher accuracy while the Pareto model is able to resume the characteristics of WWWtraffic with fewer parameters. 1

Effects of Variations in the Available Bandwidth on the Performance of the GFR Service

... into the specification documents of the ATM-Forum. The concept of the GFR service is to provide a minimum service guarantee to classical best-effort services, taking into account the frame-based nature of todays data-traffic. In this paper we present a discrete-time analysis of the GFR service and discuss the effects of variations of the bandwidth available for the GFR service. The presented method can be applied to dimension the thresholds of the algorithms used to enforce the guaranteed service

A Numerical Analysis of the M/D^b/N Queuing System

In this paper, we provide a numerical analysis of the M/D^b/N - ∞ queueing system. This system consists of an infinite buffer and N identical batch servers with batch capacity b. It serves as a model for various types of workstations in the manufacturing context. Using an approach presented by Crommelin, we derivethe distribution of the number of lots waiting in queue at arbitrary time instants and the distribution of the waiting time of lots. The results are of an exact nature and the computation is of low complexity concerning run time and memory usage

Performance of the GFR-service with constant available bandwidth

minimum service guarantee to classical best-effort services. The eligibility of frames for this service category is determined with the Frame Based Generic Cell Rate Algorithm and the transmission is guaranteed by a queuing-discipline based on two thresholds. In this paper we present a discrete-time analysis of the GFR-service under the assumption of constant available bandwidth. The presented method can be applied to dimension the thresholds of the queuing discipline used to enforce the guaranteed service.