Having multiple computers can be a little bit more complicated to handle. Networking them is also a bit of a chore. In order to network computers, you would need a device that would handle all the communications between the computers; this device is the switch. A switch is a plug
and play device that needs no configuration whatsoever in order to interconnect a number of computers. You just insert all the LAN cables from all your computers into its sockets and you would already have an established network, given that they are in the same IP range and they have the same subnet. After that, you can then configure each of the computers about what services and folders you would want it to share.
A router, on the other hand, is a device that is used to manage traffic between a network and the outside world; which is usually the internet. It has a lot of functionalities that can be configured, usually via an internet browser. A typical router would have 1 port that connects to the switch and 1 port that would connect to the internet modem. The router is another element of the network and as such, it can be accessed from the computers given that the service is allowed. Routers have multiple features including a DHCP server that allows connecting computers to request a dynamic IP whenever it connects, NAT, Static Routing, and Wireless Networking for those who prefer to use it. Routers are usually your gateway to the internet, meaning you should properly secure it unless you want someone else to enter your network and control it.
Having a router would usually mean that you would also need a switch, thus most routers sold today have an integrated 4 port switch built into it already. While owning a switch doesn’t always mean that you would need a router, thus stand-alone switches exist. As your network gets bigger and bigger, you would soon feel the need to add more switches into your network in a system called cascading. But cascading too many switches can degrade the performance of your network, so you should plan your network properly to provide a good connection.
Routers and switches are two of the components that are required to run a proper network. Along with a modem, you can have as many computers connect to the internet at once using a single internet connection.