Analytical modelling and characterization of Weighted Fair Queueing (WFQ) have recently
received considerable attention by several researches since WFQ offers the minimum
delay and optimal fairness guarantee. However, all previous work on WFQ has
focused on developing approximations of the scheduler with an infinite buffer because of
supposed scalability problems in the WFQ computation.
The main aims of this thesis are to study WFQ system, by providing an analytical WFQ
model which is a theoretical construct based on a form of processor sharing for finite
capacity. Furthermore, the solutions for classes with Poisson arrivals and exponential
service are derived and verified against global balance solution.
This thesis shows that the analytical models proposed can give very good results under
particular conditions which are very close to WFQ algorithms, where accuracy of
the models is verified by simulations of WFQ model. Simulations were performed with
QNAP-2 simulator. In addition, the thesis presents several performance studies signifying
the power of the proposed analytical model in providing an accurate delay bounds to
a large number of classes.
These results are not able to cover all unsolved issues in the WFQ system. They represent
a starting point for the research activities that the Author will conduct in the future. The
author believes that the most promising research activities exist in the scheduler method
to provide statistical guarantees to multi-class services. The author is convinced that
alternative software, for example, on the three class model buffer case, is able to satisfy
the large number of buffer because of the software limitation in this thesis. While they can
be a good topic for long-term research, the short-medium term will show an increasing
interest in the modification of the WFQ models to provide differentiated services. / Ministry of Higher Education
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/4877 |
| Date | January 2010 |
| Creators | Alsawaai, Amina S.M. |
| Contributors | Awan, Irfan U., Fretwell, Rod J. |
| Publisher | University of Bradford, School of Computing, Informatics and Media |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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