December 12, 2000, 2:40 PM — Infrastructure is everything to networks. If you have the proper infrastructure, you
can build flexible networks that efficiently reach out to your users. On the other
hand, if you don't, you need to build it before you can deploy the network you need.
Copper remains the infrastructure of choice for intrabuilding LANs. However, for
enterprise networks, the infrastructure is increasingly fiber-based. Fiber supports
Gigabit Ethernet, ATM, and Packet over SONET. With transceivers, even good
old-fashioned 10/100 Mbps Ethernet can run over fiber links.
There are two primary kinds of fiber: single-mode and multimode. The main difference
between the two is distance and cost. Multimode is typically used for shorter
distances, such as within buildings, while single-mode is normally used to span long
distances of up to several miles. Of the two, single-mode is more expensive and often
more in demand.
Slicing up the fiber
Dark fiber is like pizza. As soon as people know you have it, everyone seems to want
a slice because you can use it for everything from data to video connections. You can
even run PBX T-1 emulation over fiber.
There's a finite number of strands in each sheath of fiber, and unused strands have
a tendency to become increasingly scarce as your enterprise network grows. At first you
think you have all the fiber in the world, so you aren't hesitant to give away unused
strands for nonnetworking purposes. But as time passes and your network needs grow, you
realize you can't expand your network without the expensive task of pulling more
The moral? Be careful about what you give away. If the requested application makes
sense to you and you have enough reserve, that's fine. Otherwise, turn down the
request. Giving out fiber strands is easy, particularly when you have fiber to burn, so
to speak. However, as your network grows, getting it back can be extremely difficult.
Adding fiber is expensive, so treat your fiber infrastructure for what it is -- a
rare and valuable commodity.