There are different network topologies that you can find right now but the most common one has to be the star network. This means that the answer to this question is Star network. If in case you are not too familiar with this, this is a central hub which will be able to send the various messages to the different networks.
This is also reliable because just in case one of the nodes do not work, the other nodes will not be affected. This means that the transmission of messages will still go on as planned. The other topology nodes can still be useful for different things.
