48
backbone operating at a speed of 2.5 billion bits per second. That is just the
beginning.
What is enabling the dramatic increase in speed of the backbones is fiber optic
technology. Think of a glass fiber smaller than a human hair and imagine shining
a light through the fiber. Turn it on and you get a “1”. Turn it off and you get a “0”.
In the near term the limit of this will be 10 billion “ons” and “offs” (bits) per second
through a single fiber. That limit will soon be 40 billion bits per second. In addition
to this incredible speed through a fiber, a technology called Dense Wavelength
Division Multiplexing (DWDM) can enable more than one light to be passed
through a fiber at the same time. This is done by using multiple colors of light
called “windows” or Lambdas. Current fiber optic cables are utilizing 160
“windows” but work is underway to upgrade that to 320 “windows”. The state of
the art in research laboratories is currently approximately 1,000 windows and
some startup companies like Avanex are now talking about the possibility of
having 100,000 “windows” per fiber.
Lucent is currently building cables that contain nearly 1,000 fibers. The numbers
are staggering when you add it up. The aggregate capacity of a fiber optic cable
may be 40 billion bits per second per “window” times 100,000 “windows” times
1,000 fibers per cable. That comes out to 4 million terabits per second per cable!
There are hundreds of companies putting fiber in the street alongside water
pipes, in the ground alongside railroad tracks, and under the oceans. There are
already tens of millions of miles of fiber in place. New fiber optics companies like
Qwest, Level 3, Global Crossing, and Williams already have an aggregate
capacity that exceeds what AT&T, MCI, Sprint, and WorldCom combined
currently have in service.
An entire optical infrastructure is emerging causing the Internet to morph itself
from a wired world to an optical world. While the “last mile” is expanding from a
one inch garden hose to a 3 foot in diameter pipe, the backbones are moving
from six foot in diameter pipes to ones which are hundreds of feet in diameter.
Bill Alpert, in a December 2000 story in Barron’s called “Optical switches will be
the next big thing in data transmission” said “The optical Internet is a modern
wonder.” The backbones will not be the bottleneck.
Where does the bottleneck move to?
The bottleneck is going to move away from the “last mile” and away from the
backbones. So where does the bottleneck move to? Part of the bottleneck will
move to getting the bits from the backbone through the last mile to the end user
or business. Part of the bottleneck will be at the server. Servers are specialized
computers that deliver the web pages and video streams and music and e-
commerce applications to millions of users on the Internet through their
browsers. If you have moved to a cable modem or DSL from your former slower
speed Internet service you may not have actually noticed as dramatic an
increase in speed as you had hoped. This is partly because there are servers
 |
 |
 |