Switch

A switch is network hardware that connects devices together on a LAN. For example, a village cinema might connect its ticket till, projector control laptop and box-office computer to a switch so they can share booking files. In a wired LAN, each device connects to the switch with a cable that plugs into one of its ports.

When a switch receives data from a device, it checks which device the data is meant for and forwards it only to that device. The other connected devices do not receive a copy. Unlike a hub, which sends every piece of data to every device, forwarding only where it is needed means the network carries less unnecessary traffic and other devices' data stays more private.

Ports limit the connections

A switch can only accept as many direct cable connections as it has ports. If an 8-port switch has eight cables plugged in, there is no free port for a ninth connection. To provide more ports, you can connect another switch to a free port on the first switch. The second switch adds its own ports, so more devices can join the LAN.

A switch does not connect different networks; that is the job of a router. It also does not store files or act as a server. Its role is to connect devices within a LAN and pass data only to the device that needs it.