Hub can be defined as one common point for connecting all the network devices. Various LAN segments are connected to hub in order to organize the working of the network. A network hub connects the various ports of the optic fiber cable and helps establish a single network connection or segment.
Uses of Hubs
The early adopters of the network hub used it as a convenient substitute for expensive and efficient switches. Besides being inexpensive network hubs also serve many unusual purposes. In some special cases hub replaced network taps for the effective installation of protocol analyzer. Network hub is efficient enough to receive load of data traffic for cluster of computers. Hubs are simple and easy to use. If we however use a switch instead of a hub for the same purpose, we need to configure the switch settings. Hub can also be used to establish a loop, where it is necessary to give a connection to end users in a presentation hall. Hubs can be used for network extension the reason of this extension is that network hubs repeat every packet of data or information sent. More recently the hubs are more specifically used for small networks.
How Hub Works
The more precise and true definition of a network hub is that it is more like a variable port repeater, besides only being a common link for cluster of computers. The most common operation it performs is that it repeats all the information it receives and forward it to all PC terminals attached to it. This repetition of data results in unnecessary data traffic being sent to the network. Therefore the data is sent in bulk without the identification of its destination. Whereas switches work in more efficient way, switches control the flow of data traffic in an organized way. A switch is an intelligent device. Switches can identify easily to which it has to send data. Transfer of appropriate data packets to appropriate units thus help to increase network bandwidth. Hence we can say that the use of switches instead of hubs lower the load of unnecessary data being sent to the network. This unnecessary data flow results due to the same amount of information sent to all units irrespective of their individual needs .hubs are used for small networks, however switches can serve the various purposes of large networks. Network hubs are devices which operate at layer one (physical layer) of the OSI model, as compared to switches which work on the layer 2(data link layer) of the OSI model. Often a switch and a hub is combined to make a switching hub, which serves the basic purpose of transporting the right data packets to right place. However this network hub comes under the head of hubs and not switches.
Types of Hubs
There are three broad categories of hubs if we compare them on technical bases. Passive hubs, active hubs and intelligent hubs are three kinds of hubs most frequently used. Hubs are not often preferably used because they are considered passive devices, which do not respond to the electrical signals. Such hubs which are not capable of regenerating electrical signals to efficiently transfer data packets are known as Passive hubs. Passive hubs are often termed as concentrators. More recently there are hubs available in the market which can perform actively. Multi port repeaters which can amplify the electric signals to deliver packet of data are known as active hubs. When active hubs are developed more to be used by companies they are known as intelligent hubs. The purpose of these hubs is to preserve the space in an operation room or office. Various hubs are set one over the other to allow enough space for the human working. Intelligent hubs can also back up media and multiple protocols.