Fiber optics is faster than wireless Internet service-by a bunch
 Q: I am trying to determine what type of internet connection I should get based on theoretical speed. My question is
which connection would be faster: data streams via radio frequency (RF) or data streams via fiber optic cable
(optical)- Sean McK., San Diego, CA
A: A fiber-optic connection is faster than wireless by many orders of magnitude. A single optical fiber can carry about 3 trillion
bits per second (bps). The fastest wireless service (fixed wireless access) approaches 2 million bps. So, fiber optics can be
more than a million times faster.
Right: [NASA] Fiber-optic cables
Dense wave division multiplexing (DWDM) is the process of putting many colors of light-each carrying its own data
stream-onto a single strand of fiber-optics cable and sorting out the data streams at the other end. The extremely clever scheme
enables a single strand of fiber-optics cable to carry up to 3 trillion bits of information per second.
The two emerging technologies, wireless and fiber-optics, are difficult to compare since breakthroughs with one or the other happen frequently. Every six to
nine months the number of colors you can put on a fiber-optics strand doubles: from 4 in 1996 to 320 now, in 2001-with no increase in cost. The cable's in
place. This revolutionary technology will probably sweep the Internet just as the cheap PCs that everyone could afford swept the computing world back in the
1980s.
Think of the speed. Suppose you were to download the entire Library of Congress onto your PC using a dial-up modem transferring data at a rate of 56
thousand bps. You'd have trouble storing that much admittedly but-it would take about 82 years. A wireless connection going at 2 million bps would move
the library in a little over two years. How long would a 3-trillion-bps fiber-optics connection take? 48 seconds.
One last remark on the fiber-optics connection using DWDM: you don't share your color with anyone. It's all yours so your data through-put rate doesn't
diminish as traffic piles up on your local net. The fixed-wireless-service is a shared system and not as reliable as fiber.
Running Internet messages (i.e., TCP/IP, the Internet protocol) on wireless is also more difficult when fading occurs, says Vahid Tarokh, electrical engineering
and computer science professor at Massachusetts Institute of Technology. "This makes the practical throughput of Wireless Internet much less than the peak
rates (that are usually advertised by the providers).
Is fiber available? Bell South is installing and testing fiber-to-the-home connections in 200,000 homes in Atlanta and Miami. The fiber-optics system, fast but
not state of the art, operates at 10 billion bps. Even so, Bell South's connection only takes 4 hours to transfer the Library of Congress. In a few years, maybe
your city will have it.
(Answered by April Holladay, science correspondent, August 8, 2001)
Further Surfing:
ZD Net: The fiber optics challenge
Forbes: Fixed wireless internet access
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