Any device that can control the flow of electrical signals. A number of special-purpose switches are used in networking. For example, the following types of switches are used to control access to computers by printers, keyboards, and monitors:
In the context of controlling data flow within a network, the term “switch” is also used to describe a data-link layer device that routes frames between connected networks. Data flow switches include
In the context of high-speed Ethernet networks, the term “switch” usually refers to an Ethernet switch. Thus, the phrase “routers and switches” is understood to mean “routers and Ethernet switches.”
The term “switch” can also refer to a device used at a telco central office (CO) for establishing connections in circuit-switched services or for forwarding packets in packet-switched services.