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Chapter 6:
Understanding Network Hardware
Putting together all the necessary pieces in the proper way is the art of network
design. Chapter 15 discusses important aspects of assembling these devices so they work
together optimally, but first you need to know what they are and what they can do. The
following sections discuss these essential network devices.
Repeaters
A repeater is a device that extends the distance of a particular network run. It takes a
weak network signal in on one side, boosts the signal, and then sends it out its other
side. You most often see repeaters on Thin Ethernet networks, but they are available for
virtually any network connection. For instance, if you need to run a 100Base-T Cat-5
cable longer than 100 meters (328 feet), a repeater enables you to double that distance.
Repeaters operate at the physical layer of the OSI networking model. They do
not have the intelligence to understand the signals they are transmitting. Repeaters
merely amplify the signal coming in either side and repeat it through their other side.
(Remember that they also amplify any noise on the cable!) Repeaters are used to connect
only the same type of media, such as 10Base-2 Thin Ethernet to 10Base-2 Thin Ethernet,
or Token Ring twisted-pair to Token Ring twisted-pair. In practice, repeaters are usually
used with 10Base-2 networks (Thin Ethernet), which are discussed in Chapter 4.
Repeaters do have a small amount of intelligence that can be useful. They can
separate one of their connections from the other when there is a problem. For example,
consider two segments of Thin Ethernet that are connected using a repeater. If one of
those segments is broken, the repeater allows the good segment to continue working
within itself. Users on the good segment will be unable to connect to resources on
the broken segment, but they can still use the good segment without trouble. (But
remember that this capability does you little good if your servers are on the broken
segment and your workstations are on the good segment!) Figure 61 shows a network
extension using repeaters.
Figure 6-1.
Using repeaters to extend network length (10Base-2 Thin Ethernet shown)
Summary :
67 Chapter 6: Understanding Network Hardware Putting together all the necessary pieces in the proper way is the art of network design. You most often see repeaters on Thin Ethernet networks, but they are available for virtually any network connection. (But remember that this capability does you little good if your servers are on the broken segment and your workstations are on the good segment!) Figure 61 shows a network extension using repeaters.
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