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28 Chapter 2

As explained in Chapter 1, “Introduction to Optical Communica-
tions,” fiberoptics is not new. However, the field has been ignited by
several new uses and applications of older technologies. The tele-
phone companies were deploying the basic fiber systems in their
local architectures and then moved into Synchronous Optical Net-
working (SONET) architectures in local and metropolitan areas. We
also learned that the long-distance carriers were moving toward a
robust networking strategy using fiber and SONET in support of
their networks. Corporate users also began migrating to fiber inside
the walls of their office buildings on local area networks (LANs) or
campus area networks (CANs). The issues that inevitably surface
when discussing the use of fiber include

Cost per foot of the fiber as opposed to copper-cable plant
Cost of the electronics
Cost of the repeaters and amplifiers
Difficulty of installation

Each of these issues was, in its own right, a valid concern.The cost
issues were significant several years ago. However, technology
matures, and mass production begins driving the prices down to
more palatable and financially justifiable levels.
Suppose that we were asked by management to rewire a building
today. The first question we have to satisfy is: How much bandwidth
do we think we are going to need in the backbone of the network, and
what demands will exist to the desktop? The answer is going to be as
complex as the question. Several congruent technologies can satisfy
most of our day-to-day needs today. However, whether they can meet
the demands for the future becomes the tough part. An example of
this is the use of copper unshielded twisted-pair wires to the desktop.
Clearly, we started out with the use of the different categories of wire
to satisfy our immediate needs to the end-user terminal device. Sum-
marily, Table 2-1 presents the original design around the categories
of wire for use in a building infrastructure and the speeds that are
supported.This table is a summary of the systems in place. However,
several deviations and methods by which improvements can be
made do exist. The assumptions used in the cable specification were
that the wires would be as follows: