Information Technology Reference
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nector adapter cables, with one end matching the network or workstation equip-
ment, and the other end matching the outlet or patch panel connection. In addition,
you may need to adapt between different technologies, such as single-mode and
multimode, or copper and fiber. Just what are these issues, and how can you deal
with them?
Fiber to the Desktop
The watchword in the fiber cabling industry is “fiber to the desktop.” In the early
days of networking, this was seen as an ability to offer almost unlimited bandwidth
to the user (or at least to the user's workstation, as few of us have much bandwidth
whatsoever). The most popular option for this desktop fiber originally was OC-3 at
155 Mbps. This connection was primarily suggested because the 10BaseF options
were not considered high-speed and the 10 Mbps data rate could easily be sup-
ported on legacy Cat 3 wiring. However, a more practical problem that existed with
OC-3 was that it primarily utilized ATM, which was a rare protocol in the local area
and not very well supported by software or hardware manufacturers. FDDI was also
available as a desktop option, but at an interface cost that frequently equaled or
exceeded the cost of the equipment it was connecting.
100BaseFX and any of the 1000BaseF Gigabit Ethernet options now offer very
viable desktop fiber network connections. Of course, not many users currently need
the speed of gigabit, but certainly the network manager (and the boss) do. Equipment
interfaces are the switch/hub fiber connections and the network adapter cards in
workstations, servers, and routers. All these types of equipment now offer fiber inter-
face options. The cost of the interfaces is a matter of supply and demand. The LED
optics used with 100BaseFX are relatively cheap. Consequently, the adapter cards
and hub interfaces are within reach of the high-end copper counterparts.
Gigabit Ethernet is somewhat in transition, as copper cabling options are
emerging. Although the cost of fiber and copper Gigabit Ethernet interfaces will be
about the same initially, you can expect the price of the copper interface to drop
considerably. Even though the innovative VCSEL laser diodes that are used with
Gigabit Ethernet fiber are much cheaper than the older technology, they still repre-
sent a significant cost penalty over copper transceivers.
The installation efficiency and cost of centralized fiber cabling may actually be
a compensating factor in considering fiber to the desktop. In very large installations,
the savings of using centralized fiber over structured copper may be sufficient to dic-
tate its use. In addition, there are inherent advantages, such as interference immu-
nity, security, and higher-bandwidth future technologies that may give fiber the
upper hand.
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