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30 Chapter 2

using a multimode fiber, and the 100 base F, which is the Fast Eth-
ernet standard on multimode fiber in a backbone. Now the 1,000
base F standard (Gigabit Ethernet) is supported on multimode or
single-mode fiber in the campus. This adds a new dimension to the
use of fiber because the speeds are ever-increasing, yet the corporate
user has other issues to handle. The selection of a wiring standard is
usually based on a specific point in time. For example, 5 years ago,
one may have selected Category 3 wiring as a norm because this was
the standard for Ethernet cabling at the time. However, in a matter
of months, Category 5 wires appeared, causing heartburn for admin-
istrators who had installed the older version. In 1996 and 1997, the
use of 100 base T wiring became far more prevalent.This meant that
the building that was prewired for lower-speed networks was not
conducive to supporting the newer high-speed standard. The choices
were limited:

1. Use only 10 base T on these wires.
2. Rewire the building to support the higher speeds at 100 and
now 1,000 Mbps.
Figure 2-1 shows the growth rates for 100-Mbps Ethernet. This
figure shows the percentage of new installations that use the 100-

Growth of 100 Mbps Ethernet Usage
Figure 2-1
Growth of the 100
base T standard
1999

1998

1997

1996

0% 20% 40% 60% 80%