Hub

Hub: A hub is used in a wired network to connect Ethernet cables from a number of devices together. The hub allows each device to talk to the others. Hubs aren't used in networks with only wireless connections, since network devices such as routers and adapters communicate directly with one another.

Hubs are such simple devices — they require no configuration, and have no manuals — that their function is now included in other devices such as routers and modems.  NETGEAR no longer sells stand-alone hubs.  If you require a stand-alone appliance, use a switch instead.  Switches provide better performance and features than hubs.

A hub is rectangular box that is used as the central object on which computers and other devices are connected. To make this possible, a hub is equipped with small holes called ports. Here is an example of a hub:

Although this appears with 4 ports, depending on its type, a hub can be equipped with 4, 5, 12, or more ports. Here is an example of a hub with 8 ports:

When configuring it, you connect an RJ-45 cable from the network card of a computer to one port of the hub.

In most cases for a home-based or a small business network, you may not need a hub.