A network switch is a computer networking device that connects network segments. It was developed from the electronic hub where the hub provided a central nodal device for a star configured network. A hub, which utilises a central bus within the device, allows all star network connections to receive a broadcast frame.
A switch can connect Ethernet, Token Ring, or other types of network segments together to form a heterogenous network operating at OSILayer 2.
Switches differ mainly from hubs in that they perform microsegmentation. Microsegmentation is a term used to describe the segmentation of a collision domain into as many segments as there are circuits, minus one. This microsegmentation performed by the switch cuts the collision domain down so that only two nodes coexist within each collision domain. This way, collisions are decreased and only the two NICs which are directly connected via a point-to-point link are contending for the medium.
This point-to-point approach allows the switch to connect multiple pairs of segments at a time allowing more than one computer to transmit data at a time, without causing collisions.
There are four ways in which a switch can operate: