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networks. Most hubs are simple multiport repeaters. That is, they receive a signal on one port and repeat it to all other ports. As with repeaters, though, they also repeat any noise or corrupt signals to all ports.


There are three types of hubs:


■    A passive hub simply makes physical, electrical connections between all incoming cables and stations so that stations can communicate. Because they don’t do any repeating, passive hubs don’t require power. ARCnet is an example of a topology that uses passive hubs.


■    An active hub is powered and contains circuitry to amplify the network signals it receives. Active hubs are used most often in UTP installations of Ethernet (the most common method of cabling for Ethernet). The majority of hubs are active hubs.


■    An intelligent hub is really a subtype of the active hub. All intelligent hubs are active, but not all active hubs are intelligent. An intelligent hub is any hub that contains special features for management and configuration. Many hubs today can manage individual ports, collect traffic statistics, and power up/power down from a remote station on the network. These features make an intelligent hub more complex and, thus, more expensive.


When you install a hub, you simply plug patch cables from the patch panel into the ports on the hub. These hub-to-patch-panel patch cables are typically very short (less than 1 meter, or about 3 feet). If you have an intelligent hub, you may be able to configure ports to be active or inactive using special hub-configuration software.

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