Using cable Internet services for
the first time can be a breathtaking experience.
Images and text flash before your eyes instantly. Full-motion video
and audio play without jitter. When you see this, you realize that
this was how the Internet was meant to be. Even for Internet
oldtimers, it's like a whole new world.
The cable television network has emerged as the
early leader in providing such high-speed data access in the home.
With more than a million cable modern subscribers now in North
America, the system has matured from a string of experimental
deployments in 1995 to a mainstream service available in most major
Internet access over cable runs at speeds up to
100 times those of the traditional dial-up world. This raw speed is
the catalyst producing the dramatic change to typical Internet
services. And the connection is "always on," enabling
users to call up a site immediately as the spirit moves them. Gone
are the days of having to log in to the network.
How does cable achieve these data rates? In the
late 1980s and early 1990s cable operators started deploying fiber
optics in their networks. Cable companies ran fiber out to
individual neighborhoods and made use of existing network of coaxial
cable to reach the "last mile" to each home. The optical
fibers connect the cable operator's central facility (the "head
end") to each neighborhood area (the "node"). Fiber
has greatly increased the capacity and reliability of cable TV
networks. With a cable Internet connection, data occupy the space of
one TV channel. Tune to this channel with your TV, and you'll see
only static, but connected to your cable modem it becomes a data
stream flowing at about 40 megabits per second (Mbps), which can
then be relayed to your personal computer at rates up to 10 Mbps.
the fiber network also allow signals to be sent back from the home
to the head end, making telephone and interactive vidio services