Information Technology Reference
In-Depth Information
lines, each category/class allows a wide range of applications in addition to the
classic Ethernet ones.
However, it is quite possible and probably desirable for a manufacturer to build
cabling components that actually exceed the minimum specifications of a particular tar-
geted category. For example, at one time, Category 5 was considered the ultimate and
was a manufacturing challenge. Soon the leading manufacturers discovered that they
could use innovative designs and production methods not only to comply with
Category 5, but to actually exceed the parameter requirements, often by a significant
margin. These better quality cables and connectors were initially called
Enhanced
Category 5
and ultimately were found to be all but necessary to achieve Gigabit
Ethernet operation. Now the same has happened with Category 6, resulting in
Augmented Cat 6, or AC6. Some exceed Cat 7 preliminary specs by more than double.
The lesson here is that good engineering can create components that have bet-
ter performance than the standards require. Can you benefit from those enhance-
ments? Yes, you can, particularly if you operate near the limits of distance or data
rate. Better still, you may be able to plug in new technologies that were not even
dreamed of when the cable standard was defined. Those of us who specified
enhanced Category 5e were rewarded with the ability to jump to Gigabit Ethernet
over copper as soon as it became available, because our cable already met the TSB-
95 and/or Category 5e performance levels that were later made part of the -B stan-
dard. By the same token, enhanced cable and components for Category 6 and 7
already exist, and may well prove to offer more long-term stability as well.
You should buy the best cabling components you can afford, keeping in mind
that the network technologies of today are transient and will be obsolete in a few
years. Stepping beyond the envelope may be a little risky, as some predicted tech-
nologies never reach critical market mass. So, try to plan for one or two steps in
increased network speed and leave the rocket science for the experimenters. In that
way, you will have a network infrastructure that will provide optimum performance
at minimum cost with a reasonable useful life.
The importance of fiber-optic cable cannot be overemphasized. Fiber cable has
unique characteristics that make it suitable in many types of high-bandwidth,
high-interference, and interbuilding applications. As recent very high-speed tech-
nologies have emerged, fiber interfaces have been developed and marketed consid-
erably in advance of their copper counterparts. Whereas copper cables are limited
to 100 m for almost all applications above 100 Mbps, such a short distance is triv-
ial for fiber.
