Hub

A hub, more commonly known as a network hub or concentrator, is a device that connects multiple fiber optic or twisted paired Ethernet devices together. When interconnecting these devices, they perform as a single network segment, thus making the device a type of multiport repeater. A hub functions at layer 1 of a network; which is the physical layer of the OSI model. Because of this, layer 1 switch is a term often used to represent a hub. A hub may be included with an AUI (attachment unit interface) or BNC connector. These components enable connection with 10BASE2 and 10BASE5 network segments. It may also take on the responsibility of transmitting a jam signal to each port when a collision is detected. Hubs have basically become obsolete due the availability and affordable nature of network switches. At the same time, hubs remain active in older installations and certain applications.