Document Type Master's Dissertation Author Strauss, Marthinus David URN etd-04112007-120231 Document Title A Simulation study of traffic conditioner performance Degree MSc (Computer Science) Department Computer Science Supervisor
Advisor Name Title Prof D G Kourie Keywords
- traffic conditioners
- Quality of service
Date 2006-05-04 Availability unrestricted AbstractA traffic conditioner is an element of the Differentiated Services architecture. This
architecture is used to regulate quality of service in computer networks. Five traffic
conditioners were selected for the study. These include the token bucket marker and
four conditioners described in RFCs. The contribution of this dissertation is two-fold.
Firstly, it presents process algebra models of the five identified traffic conditioners.
These models provide succinct descriptions of the conditioners thereby highlighting essential
features. The models are, however, not intended for model checking purposes,
but rather serve as a convenient pedagogical device. The second and main contribution
of the dissertation is a simulation study to investigate the relative performance of
the five traffic conditioners across a range of simulated scenarios in which traffic patterns
and subscription levels are varied in a fixed network topology. Two performance
measures—TargetRatio and GreenRatio—are defined, justified, and used to compare
the traffic conditioners. The GreenRatio measure was found to be more discriminating
than the TargetRatio measure. A variant of the GreenRatio measure was used to
further illuminate the differences between conditioners. The simulation results suggest
that the performance of the conditioners are sensitive to parameter values such
as token bucket size and that bursty traffic patterns are particularly sensitive to these
parameters. Under such bursty conditions, these parameters should be chosen with care.
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