This paper presents one of the features of DS (Differentiated Services) architecture, namely the queuing or congestion management. Packets can be placed into separate buffer queues, on the basis of the DS value. Several forwarding policies can be used to favor high priority packets in different ways. The major reason for queuing is that the router must hold the packet in its memory while the ou...

Two common approaches for predicting the response times of distributed enterprise applications on new server architectures are solving queuing models and extrapolating from previously gathered performance data. The dynamic recalibration of a layered queuing model and a historical model is investigated experimentally using the IBM Websphere Performance Sample benchmark. It is found that these mo...

We present algorithms for approximating time-varying performance parameters for a Gt/G/c queuing system and for networks of such stations. The key ingredient is a formula for computing approximate sojourn time distributions for a Gt/G/c queuing system with time-varying arrivals and phase-type service times. The formula is based on transient Little laws expressing expected queue lengths and outp...

Recently, techniques have been developed for estimating confidence intervals when simulating stochastic systems having a regenerative structure. These techniques are applied to the simulation of a queuing model of a computer system’s automated tape library. Theoretical and practical issues related to the application of these techniques are addressed. An interesting feature of the automated tape...

At high transmission speeds, complexity of implementation for fair queuing disciplines can impose a bottleneck to the overall system performance. Available scheduling algorithms set a fixed trade off between fairness and complexity, fairer systems involving more operations per packet and vice versa. In this paper first a new fair queuing scheme is proposed, with almost the same fairness and com...

Abstract: During the last few years message queuing and workflow systems have been established as major elements of the software stack. In practice, this middleware is often used to cope with aspects of data federation: Message queuing technology is exploited for application integration. Workflows extend the notion of stored procedures in a federated environment and provide transaction manageme...