A switch is usually used to set up a LAN and is an important network element for LAN communication. It uses the Layer 2/Layer 3 switching function to quickly forward data packets.

Firewalls are deployed at the network border to control incoming and outgoing network access. Security protection is the core feature of firewalls.

Routers are used to connect different networks and use routing protocols to communicate with each other so that packets can be forwarded to the correct destination.

Routers and switches are mainly used to forward data, while firewalls are used to control data.