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Cable modems enable
two-way, high-speed data transmissions using the same coaxial lines
that transmit cable television. Some cable service providers are
promising data speeds up to 6.5 times that of T1 leased lines. This
speed makes cable an attractive medium for transferring large
amounts of digital information quickly, including video clips, audio
files, and large chunks of data. Information that would take two minutes to download using ISDN can be downloaded in two seconds through a cable-modem connection.
Cable-modem access provides speeds superior to leased lines, with
lower costs and simpler installation. When the cable infrastructure
is in place, a firm can connect through installation of a modem or
router. And because cable modems do not use the telephone system
infrastructure, there are no local-loop charges. Products such as
the Cisco uBR904 universal broadband router cable modem make cable
access an even more attractive investment by integrating a fully
functional Cisco IOS® router, four-port hub, and cable-modem into one unit. This combination allows businesses to replace combinations of routers, bridges, hubs, and single-port
cable modems with one product.
Cable modems provide a full-time
connection. As soon as users turn on their computers, they are
connected to the Internet. This setup removes the time and effort of
dialing in to establish a connection. The "always-on"
cable connection also means that a company's "information
pipe" is open at all times. This setup increases the
vulnerability of data to hackers and is a good reason to install
firewalls and configure cable routers to maximize security.
Fortunately, the industry is moving toward the standardization of
cable modems, and the move is likely to address encryption needs.
For instance, new models of the Cisco uBR904 cable modem will
provide IP Security (IPSec) and firewall capabilities. These
features protect company LANs and provide virtual private network (VPN)
tunneling, with options for authentication and encryption.
Because the connection is permanently
established, cable modems cannot dial in to different networks or
locations. Any network connection must take place through the
Internet. For example, employees using a cable modem at home to surf
the Web can connect to a company LAN only if the business connects
its LAN to the Internet. Moving through the Internet in this way can
restrict the speedy connection of cable modems. To address this
problem, many cable access service providers are in the process of
developing services that combine cable and T1 connections to provide
fast and reliable remote office-to-corporate network connections.
Availability may be the biggest
barrier to cable-modem adoption by businesses because only a few
office buildings have been outfitted for cable reception, compared
to the almost 85 percent of households in North America that are
wired for cable.
Some cable operators are in the
process of replacing traditional one-way cable systems with the more
interactive two-way architecture known as hybrid fiber coaxial (HFC).
Due to the magnitude of this upgrade and the need to expand networks
to include businesses, the market penetration of cable modems is
expected to lag behind DSLs.
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