This thesis presents a study and analysis of the major influences on network cost and their
related performance. New methods have been devised to find solutions to network
optimisation problems particular to the AT&T ISTEL networks in Europe and these are
presented together with examples of their successful commercial application. Network
performance is seen by the user in terms of network availability and traffic delay times. The
network performance is influenced by many parameters, the dominating influences typically
being the number of users accessing the network, the type of traffic demands they place upon
it and the particular network configuration itself. The number of possible network
configurations available to a network designer is vast if the full range of currently available
equipment is taken into account. The aim of this research has been to assist in the selection
of most suitable network designs for optimum performance and cost.
This thesis looks at the current differing network technologies, their performance characteristics
and the issues pertinent to any network design and optimisation procedures. A distinction is
made between the network equipment providing user 'access' and that which constitutes the
cross country, or *core\ data transport medium. This partitioning of the problem is exploited
with the analysis concentrating on each section separately.
The access side of the AT&T ISTEL - UK network is used as a basis for an analysis of the
general access network. The aim is to allow network providers to analyse the root cause of
excessive delay problems and find where small adjustments to access configurations might lead
to real performance improvements from a user point of view. A method is developed to allow
statistical estimates of performance and quality of service for typical access network
configurations. From this a general method for the optimisation of cost expenditure and
performance improvement is proposed.
The optimisation of both circuit switched and packet switched computer networks is shown to
be difficult and is normally tackled by the use of complex procedures on mainframe computers.
The new work carried out in this study takes a fresh look at the basic properties of networks
in order to develop a new heuristic method for the design and optimisation of circuit switched
core networks on a personal computer platform.
A fully functional design system was developed that implements time division multiplexed core
network design. The system uses both a new heuristic method for improving the quality of
the designs and a new 'speed up' algorithm for reducing times to find feasible routes, thereby
dramatically improving overall design times. The completed system has since been used
extensively to assist in the design of commercial networks across Europe.
Date of Award | 1993 |
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Original language | English |
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Awarding Institution | |
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COMPUTER NETWORK ANALYSIS AND OPTIMISATION
RAY, G. P. (Author). 1993
Student thesis: PhD