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While building a flexible, effective and high performance network
it is very important to think about the type of hub that can help you in
building the type of network you want to build.

What is HUB?
As the name suggests, the meaning of hub is a center of activities. In network
terminology, a hub is a device where the entire connecting mediums come
together. A hub is a medium used to collect signals from the input line(s) and
redistribute them in various available wirings around a topology (topologies
such as: Arcnet, 10base-T, 10base-F etc). Hub basically acts as signal splitter,
it accepts signal through its input port and outputs it to the output ports.
Some hubs help in regenerating the weak signals prior to sending them to the
intended output lines, whereas some hubs help in synchronizing the data
communication (in simple words, the hub not only provide the mean of interface
within the network, it also provides some additional and useful features).
Sometimes multiple hubs are interconnected in the network. Generally hubs are
used more commonly where star topology is used.
Need of HUB:
Generally when we build a network using two or more computers, we need a hub.
However, it is possible to connect two computers to each other directly without
the need of hub but when we add a third computer in the network, we need a hub
to allow a proper data communication within the network.
Types of HUB:
There are many types of hubs with various features/specifications, which provide
the type of functionality you need in building network. There are three main
types of hubs: Passive hub, Active hub and Intelligent hub.
Passive Hubs:
As its name suggests, passive hubs are the ones, which does not provide any
additional feature except for working just as an interface between the topology.
These types of hubs do not help in rectifying/enhancing the signals they pass on
in the network, in terms they do not help in enhancing the performance of the
network/LAN. It is very hard to get any help from the passive hubs while
troubleshooting in case if there is any fault in the hardware or the network. A
passive hub simply receives signal(s) on input port(s) and broadcasts it (them)
on the output port(s) without even rectifying it (them).
Active Hubs:
As you must have guessed from the name, active hub is a type of hub that take
active participation in data communication within the network/LAN. Active hubs
come with various features, such as receiving the signal (data) from the input
port and storing it for sometime before forwarding it, this feature allows the
hub to monitor the data it is forwarding, some hubs come with a feature that
helps in transmitting data that has high priority before the data that has lower
priority (this feature is very important for some applications and some type of
networks), some hubs help in synchronizing data communication (by retransmitting
the packets, which are not properly received at the receiving computer or by
adjusting re-transmission of the data packets to compensate timing), and some
active hubs come with a feature that rectify the data/signal before forwarding
it in the network/LAN.
Active hubs also help in troubleshooting at certain level. If there is a
bottleneck within the network/LAN, active hubs can be used to find out the
problem at certain extent. Active hubs have some benefits over the use of
passive hubs; however, active hubs are more expensive than passive hubs as they
provide additional features.
Intelligent Hubs:
Intelligent hubs add some more features to that provided by the active hubs. An
intelligent hub provides all the features of a passive and an active hub; it
also provides some features, which help in managing the network resources
effectively and efficiently. Intelligent hubs help in improving the performance
of the network/LAN that you are using. As an active hub helps in finding out
where the problem persists, an intelligent hub itself finds out the problem in
the network, diagnoses it and tries to rectify it without letting the problem
hamper the performance of the network. Intelligent hubs provides feature that
helps in determining the exact cause and exact place of the fault, this saves
lot of time and energy which otherwise would have been required for finding out
the exact place of fault and identifying the solution for it. Another feature of
intelligent hub is that they can decide which packet goes in which output line,
this helps in controlling and minimizing data traffic in the network, which
results in improved performance of the network/LAN.
Intelligent hubs also help in managing the data communication within the
network, it recognizes the slower devices automatically and helps them to
transmit the data with their own speed, and during this time the hub manages the
traffic within the network effectively. This feature also improves the
performance of the network manifolds. An intelligent hub also adopts the changes
in the network very easily and it also supports different technologies without
need of changing anything in configuration.
Now a day, as the technology is progressing exponentially at every second,
bigger and complex networks are built and need for hubs with additional features
is increasing. The hubs are also being developed to incorporate the new features
and help in building high performance, flexible and more manageable networks.
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