Ethernet Network Switches

Network Switches-a basic introduction. 

A switch is used in a wired network to connect to other devices using Ethernet cables. The switch allows each connected device to talk to the others. ... Switches allow you to control who has access to various parts of the network. Switches allow you to monitor usage.

A network switch (also called switching hub, bridging hub, officially MAC bridge) therefore is a computer networking device that connects devices on a computer network by using packet switching to receive, process, and forward data to the destination device.

A network switch is a multiport network bridge that uses hardware addresses to process and forward data at the data link layer (layer 2) of the OSI model. Some switches can also process data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches.

Switches for Ethernet are the most common form of network switch. The first Ethernet switch was introduced by Kalpana in 1990. Switches also exist for other types of networks including Fibre Channel, Asynchronous Transfer Mode, and InfiniBand.

Unlike less advanced repeater hubs, which broadcast the same data out of each of its ports and let the devices decide what data they need, a network switch forwards data only to the devices that need to receive it.