A gateway and a router are needed to ensure that connections are going to be clear. The router will have the ability to send the needed data to different locations that will be specified based on the address that will be given out.
The gateway is known to be a network point which means that it will also serve as another entrance so that another network can become available. If you would check out the different parts of the internet, you will notice that there are some stopping points that are available. These stopping points can be gateway nodes or it can also be host nodes.