Switch: A switch is a networking device that connects devices on a local area network (LAN) by using packet switching to forward data to the destination device. It operates at the data link layer of the OSI model and is used to create and manage communication paths between devices on a network.

Firewall: A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between an internal private network and the public internet or other networks. The firewall can allow or block specific types of traffic based on its security policy, protecting the network from unauthorized access and potential threats.

Router: A router is a networking device that is responsible for directing the traffic between different networks. It acts as a central point that connects multiple devices or networks together and determines the most efficient path for data packets to reach their destination. Routers operate at the network layer of the OSI model and use routing tables and protocols to make decisions on how to forward data packets.