Cable modems provide an alternative to Digital Subscriber Lines (DSL) for a
fast, broadband connection to the Internet. Like DSL, cable modems provide higher
speeds than traditional dial-up modems. And cable modems offer constant connectivity,
appropriate for residential and small business use. Both DSL and cable technologies
allow multiple computers to be networked and to share the Internet connection—a
feature particularly important for small businesses that cannot afford an expensive
leased line. The speeds of DSL and cable services are close to those previously
available only through expensive leased lines, at a fraction of the cost.
Coverage in Most of the United States is Extensive…
According to industry sources[2],
coaxial cable infrastructure now runs near 105 million households in the United
States and Canada. Seventy-five percent of these households are cable subscribers.
Sixty percent of the cables have been upgraded to provide high-speed data. As
a result, over 15 million households use cable modems—twice as many subscribers
than residential DSL users. [3]
But Coverage in Appalachia is Below That in the Rest of the U.S.
According to the Appalachian Regional Commission's study Links to the
Future, the majority of non-metropolitan communities in the Region do
not have access to either DSL or cable modems. That study is being updated
with new data, but the same factors that drive up the costs of plant upgrades
in many Appalachian communities—terrain and sparse population—still exist,
and still serve as a barrier to broadband access equal to that in the rest
of the nation.
In rural areas, there may be few—or zero—options for high-speed Internet service.
Cable TV systems were created to be one-way streets, designed to send information
in one direction from a head-end to your television. The Internet is not only
a two-way street but a superhighway. Enabling cable systems to handle both directions
of information—that is, to let people watch CNN and send email simultaneously—requires
changes to cable infrastructure.
Changes to Cable TV Infrastructure Are Required to Provide Internet Access
Changes in the infrastructure can include replacing much—though not all—of
a system's copper coaxial wire with fiber optic cables to handle the additional
traffic. The bottom line: the more fiber optic cables that are installed in
the network, the higher capacity the network will have. In addition to replacing
wires, cable operators will need to invest in expensive networking equipment
to upgrade their cable TV network so it can also operate as a data network.
Such networks are called Hybrid Fiber-Copper networks (HFC) and are the most
popular way to upgrade cable infrastructure.
Once upgraded, a cable network is often capable of transferring data at rates
significantly higher than DSL or expensive leased lines. However, unlike DSL,
a cable connection on a hybrid network is not dedicated. That is, you will
share bandwidth with up to 2,000 of your neighbors, depending on how many
have cable modems.
Changes to infrastructure don't require changes to the wires that run into
homes. But instead of plugging wires into a TV, they are plugged into a cable
modem. The modem then filters and splits the incoming information, sending
TV signals to your television and sending the data stream to your computer
through either an Ethernet or USB connection. The cable modem also manages
the data from your PC back to the cable network.
Choosing Between DSL and Cable Modems
If there are high-speed options in your community, research them. Rating one
service as superior to another is impossible, as pricing and offerings vary
widely across the region and will affect your decision. And providers can offer
different levels of access—more speed for more money.
Cable Modems Can be Fast, but Speed Varies As of this writing, a typical offering from cable providers is 1.5Mbps downstream and 256Kbps upstream for under $45 a month for cable subscribers. However, cable
operators don't advertise specific speeds. Instead, some operators say only
that the cable modem speed is "up to 50 times faster than dial-up."
Consumers should insist that the operator specify the bandwidth.
Connection speeds of cable modems are particularly
affected by the number of users actively sharing the service on same branch
of the network. The number of users varies during the day, so expect to see
variations—often significant ones—in bandwidth availability.
Though you can't change the performance of the modem, you can adjust your computer's
operating system. There are a number of published tweaks[1]
for the various versions of Microsoft Windows that will speed a computer's interaction
with the modem. (The same applies to DSL.) Questions to Consider Before Choosing a Service
- What will you use the service for?
- Do you need significant bandwidth to send information, or will you use
it primarily to surf the Internet, where upstream bandwidth is not as critical?
- Will you have a web server or a local area network?
- How many other customers are on your branch? 200? 500? 1,000? (Contact
your local cable provider for this information.) If you think there may be
many users on your branch—and it will degrade the service too much—you might
want to consider purchasing a higher grade of service.
As for DSL, performance often declines as the distance increases from the
telephone company's central office. If your home or office is more than three
miles away from the central office, performance can deteriorate significantly.
What the Future Holds: Cable Services Will Continue to Expand
Cable operators invest significantly to upgrade their networks, so they
are seeking to offer more services and increase the return on their investment.
With the increasing reliability of Voice over IP technology (Internet telephones)
most large cable operators are planning to offer telephone services in the near
future. AT&T and Cox currently have over 1.8 million voice customers on
their networks. The addition of telephone service provides an opportunity to
bundle cable, Internet, and telephone services over one line. Bundling usually
carries a significant discount to the consumer, compared with buying services
separately.
Other services the industry is investigating or testing include: on-demand
video (virtual Blockbuster); access to enormous audio and video libraries;
and localized content.
The current and emerging standards that guide cable modem technology in the
United States will lead to widespread adoption of new uses for cable networks.
Footnotes:
[2] Cable Datacom News, July 2003
[3] Cable Datacom News, May 2003
Related links:
Telecommunications
Sources of Funding
Best Practices
Examples of ARC Telecommunications Projects
Research and Data
News and Events
Frequently Asked Questions
Spotlight on Telecom Issues
Directory of Telecom Resources
|