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Dated: Jun. 20, 2012
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Networking In General
Overview of Network Hubs
Network hubs were the central devices that network administrators used to use to establish a network setup using Star Topologies. Network hubs had multiple RJ-45 ports integrated in them and were used to connect one end of the LAN cables that had RJ-45 connectors crimped to them. The other end of the cables were connected to the RJ-45 ports available on the PCs. Network hubs were available with 4, 8, 16 and 24 ports. Administrators also used to cascade two hubs for larger network setups. Cascading means that one RJ-45 port of one hub connected to the RJ-45 port of the second hub in order to have increased numbers of RJ-45 ports.
Twisted pair cables were used to connect PCs to the network hubs and one network hub to the other. Since twisted pair cables only carry data signals up to 100 meters, repeaters were used to allow signals to travel at longer distances.
Network hubs are now considered obsolete because of their slow speed and the collisions that occurred in them while transmitting data. Network hubs are no longer available in the market.
Types of Network Hubs
There were mainly two types of network hubs available in the market. They were:
Passive Hubs: These network hubs did not require power supply and were available at cheap rates. Passive hubs did not regenerate the incoming packets before forwarding them to the destination PCs. Therefore the maximum total distance that data signals used to travel (from source computers to the destination computers), in case of passive hubs, was 100 meters. In case the distance between two connected computers was more than 100 meters, administrators were required to use repeaters to allow the data signals to travel at longer distances.
Active Hubs: These network hubs required power supply and were expensive as compared to passive hubs. Active hubs used to regenerate the incoming packets before the packets were forwarded to the destination computers, and therefore the maximum total distance that data signals used to travel, in case of active hubs, was 200 meters. However, repeaters were still required in case data signals had to travel for more than 200 meters. Active hubs were also known as Multiport Repeaters as they used to regenerate data packets so that they can be sent to longer distances. Since repeaters had only two ports in them, active hubs were preferred when repeaters were required.
Network Hubs - Physical vs. Logical Topologies
As mentioned above, network hubs were used to establish networks using Star Topologies, because of their internal circuits, which used to transmit data using bus oriented method, logical topologies of network hubs still remained Bus.
Since in Bus Topologies large number of collisions used to take place, the topologies and all the devices that used to work on the identical concept (for example network hubs) are now considered obsolete and are out of the market.
Network hubs are now replaced by LAN switches that work far more efficiently and provide enhanced speed.
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