What is Hub
In general, a hub is the central part of a wheel where the spokes come together. The term is familiar to frequent fliers who travel through airport “hubs” to make connecting flights from one point to another. In data communications, a hub is a place of convergence where data arrives from one or more directions and is forwarded out in one or more other directions. A hub usually includes a switch of some kind. (And a product that is called a “switch” could usually be considered a hub as well.) The distinction seems to be that the hub is the place where data comes together and the switch is what determines how and where data is forwarded from the place where data comes together. Regarded in its switching aspects, a hub can also include a router.
1) In describing network topologies, a hub topology consists of a backbone (main circuit) to which a number of outgoing lines can be attached (“dropped”), each providing one or more connection port for device to attach to. For Internet users not connected to a local area network, this is the general topology used by your access provider. Other common network topologies are the bus network and the ring network. (Either of these could possibly feed into a hub network, using a bridge.)
2) As a network product, a hub may include a group of modem cards for dial-in users, a gateway card for connections to a local area network (for example, an Ethernet or a token ring), and a connection to a line (the main line in this example).
Two Kinds Of Hubs
There are two primary types of hubs in the computing world: 1) network hubs and 2) USB hubs.
1. Network hub
A network hub is a device that allows multiple computers to communicate with each other over a network. It has several Ethernet ports that are used to connect two or more network devices together. Each computer or device connected to the hub can communicate with any other device connected to one of the hub’s Ethernet ports.
Hubs are similar to switches, but are not as “smart.” While switches send incoming data to a specific port, hubs broadcast all incoming data to all active ports. For example, if five devices are connected to an 8-port hub, all data received by the hub is relayed to the five active ports. While this ensures the data gets to the right port, it also leads to inefficient use of the network bandwidth. For this reason, switches are much more commonly used than hubs.
2. USB hub
(1) A USB hub is a device that allows multiple peripherals to connect through a single USB port. It is designed to increase the number of USB devices you can connect to a computer. For example, if your computer has two USB ports, but you want to connect five USB devices, you can connect a 4-port USB hub to one of the ports. The hub will create four ports out of one, giving you five total ports. The USB interface allows you to daisy chain USB hubs together and connect up to 127 devices to a single computer.
(2) Some USB hubs include a power supply, while others do not. If you’re connecting basic devices like a mouse, keyboard, and USB flash drive, an unpowered or “passive” USB hub should work fine. However, some peripherals, like external hard drives and backlit keyboards, require additional electrical power. In order for these types of devices to function through a USB hub, you may need use a powered or “active” hub that provides 5 volts of power to connected devices.