| |
Once the initial
decisions have been made, the network planning process involves
three main steps:
· Topological design: This stage involves determining where
to place the components and how to connect them. The (topological)
optimisation methods that can be used in this stage come from an
area of mathematics called Graph Theory. These methods involve determining
the costs of transmission and the cost of switching, and thereby
determining the optimum connection matrix and location of switches
and concentrators.
· Network-synthesis: This stage involves determining the
size of the components used, subject to performance criteria such
as the Grade of Service (GoS). The method used is known as "Nonlinear
Optimisation", and involves determining the topology, required
GoS, cost of transmission, etc., and using this information to calculate
a routing plan, and the size of the components.
· Network realization: This stage involves determining how
to meet capacity requirements, and ensure reliability within the
network. The method used is known as "Multicommodity Flow Optimisation",
and involves determining all information relating to demand, costs
and reliability, and then using this information to calculate an
actual physical circuit plan.
These steps are interrelated and are therefore performed iteratively,
and in parallel with one another. The planning process is highly
complex, meaning that at each iteration, an analyst must increase
his planning horizons, and in so doing, he must generate plans for
the various layers outlined above. |
|