Hub

What is a 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.
Examples of hubs.

What is switch?

A network switch or switching hub is a computer networking device that connects network segments.
The term commonly refers to a network bridge that processes and routes data at the data link layer (layer 2) of the OSI model. Switches that additionally process data at the network layer (layer 3 and above) are often referred to as Layer 3 switches or multilayer switches.
The term network switch does not generally encompass unintelligent or passive network devices such as hubs and repeaters.
                                                               Amitabh Kumar (9015123133, 9811006683)
                                                                                    www. ITRD.CO.IN, AmitSintu@Gmail.com