There are number of factors that govern the selection of topology for a network, the most important of which are as following :
(a) Cost – For a network to be cost effective, one would try to minimize installation cost. This may be achieved by using well understood media and also, to a lesser extent, by minimizing the distances involved.
(b) Flexibility – Because the arrangement of furniture, internal walls etc. in offices are often subject to change, the topology should allow for easy reconfiguration of the network. This involves moving existing nodes and adding new ones.
(c) Reliability – Failure in a network can take two forms. Firstly, an individual node can malfunction. This is not nearly as serious as the second type of fault where the network itself fails to operate. The topology chosen for the network can help by allowing the location of the fault to be detected and to provide some means of isolating it
