Switches and Hubs

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 receive a broadcast frame.

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. (#segments = # circuits - 1). 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

New Term: A collision domain is a logical area in a computer network where data packets can "collide" with one another, in particular in the Ethernet networking protocol. A collision domain can be a single segment of Ethernet cable in shared-media Ethernet, or a single Ethernet hub in twisted-pair Ethernet, or even a whole network of hubs and repeaters.

In general, a Hub is a central node in a network. The term comes from the analogy to a wheel's hub, the center.

A hub is a computer networking device that connects multiple Ethernet segments together making them act as a single segment. When using a hub only one computer connected to the hub is able to transmit at a time. With a hub every attached device shares the same broadcast domain and the same collision domain.

(from Casey's draft, originally)

Good explanation, but probably too difficult to use as is.