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Chapter 2
Connecting the Switch Block
Distance
The distance that 10BaseT can run and be within specification is 100 meters
(330 feet). The 100 meters includes the following:
Five meters from the switch to the patch panel
Ninety meters from the patch panel to the office punch-down block
Five meters from the punch-down block to the desktop connection
This doesn't mean that you can't really run more then 100 meters on a cable
run; it just is not guaranteed to work.
FastEthernet
FastEthernet is 10 times faster than 10Mbps Ethernet. The great thing about
FastEthernet is that, like 10BaseT, it is still based on the Carrier Sense Mul-
tiple Access/Collision Detection (CSMA/CD) signaling. What this means is
that you can run 10BaseT and 100BaseT on the same network without any
problems. What a nice upgrade path this type of network can give you.
You can put all your servers on 10BaseT and upgrade only the clients to
100BaseT if you need to. However, you can't really even buy a PC that
doesn't have a 10/100 Ethernet card in it anymore, so you really don't need
to worry about compatibility and speed issues from the user's perspective.
Use FastEthernet at All Three Layers
FastEthernet works great at all layers of the hierarchical model. It can be
used to give high performance to PCs and other hosts at the access layer, pro-
vide connectivity from the access layer to the distribution layer switches, and
connect the distribution layer switches to the core network. Connecting a
server block to the core layer would need, at a minimum, FastEthernet or
maybe even Gigabit Ethernet.
IEEE Specifications for FastEthernet
There are two different specifications for FastEthernet, but the IEEE 802.3u
is the most popular. The 802.3u specification is 100Mbps over category 3 or
5, twisted-pair (typically just category 5 or 5 plus is used for FastEthernet).
The second Ethernet specification, called 802.12, used a different signaling
technique, which was more efficient than the CSMA/CD access method. The
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