By Miles :)
The star network is a very useful network for many reasons... Such as, within the network, when one of the outer devices stop working, it still will carry on in it's routine unlike the bus or ring network.
There are a fair few amount of disadvantages for the network. Such as, because there are so many wires needed, it is a very expensive network, probably the most expensive of the three. Also, if the main hub/switch stops working, it disables the rest of the devices ability to join the network, and the other devices won't work either.