boyboyds@yahoo.com wrote:
> My understanding of Internet is somewhat rudamentary and I have a
> question for you people. How is Fiber Optic cables make my Internet
> connection faster if the rest of the world is using copper cables? Are
> we all wired together in one global web network?
>
> Thanks,
> Boy.
>
The Internet is divided into "roadways", just like the highway system.
There are small, two lane, local roads. And there are the major highways,
with many lanes on either side of the road.
http://www.cybergeography.org/atlas/cox_1678_large.jpg
The connection from your Internet provider, to your house, could be done
with wires. The data rate is normally pretty low.
At the Internet provider, they "concentrate" all of the traffic from
thousands of users connected to each multiplexer. Not everyone
downloads big files at the same time, so there is less traffic than
you might think. There might be 1000 people with 1 megabit per second
plumbing, but perhaps only a total of 100 megabits per second of traffic.
Your Internet provider, connects to a larger Internet provider. The
connection will likely happen with a fiber optic cable.
Fiber optics can carry a lot of traffic. More than one optical wavelength
can be used. I think a single wavelength could carry in the neighbourhood
of 40Gb/sec, enough for many many Internet providers, and perhaps a single
fiber could carry all the traffic for a small city.
Fiber optics are relatively expensive, so you really want to be using
the fiber, to help pay for it. Empty fiber cables don't pay for themselves.
There are communities, that are wiring the last mile of the Internet with
fiber optics. Some people have "fiber to the home" (I'm not really up
on the latest acronyms for this). The fiber cabling and optical methods
used, won't be quite as sophisticated as the major Internet highways
would be, but that helps keep the cost down. The problem with fiber
optics, is the cost is still a bit higher than using copper. But the
companies that are currently installing fiber optic interconnect, are
hoping that new services, like movies on demand, would help pay for
the investment in the new fiber optic cables.
http://en.wikipedia.org/wiki/Fiber_to_the_home
Fiber has tremendous bandwidth. Wires less so. A major achievement years
ago, was to connect two distant cities in Canada, at 274Mb/sec, via a
high voltage coax cable (the high voltage powered buffer amplifiers
along the route). Now, one fiber optic cable, can carry 40000Mb/sec on
a single wavelength, and the cost of installing that one fiber, is a
lot cheaper than stringing the fat 274Mb/sec coax. When the bulldozer
digs a trench for fiber optic cable, the cable used may have dozens
of individual fibers. If you do a bit of multiplying, I think you can
see that fiber is the best kind of interconnect for the "major
highways" of the Internet.
And if this is a homework assignment, don't forget to give me
credit, when you copy & paste :-)
Paul
Fiber Optics question 
Linear Mode
