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Network Connectivity
Glossary Analog Dial-up:
The slowest and least reliable networking medium,. Available
anywhere that you can get a telephone dial tone. This classic method
is fine for users to get email and do some casual surfing. Most
modern consumer modems claim 56Kbps throughput, but the FCC has only
approved up to 53Kbps over any phone
line. Realistic connection speeds are actually 26.4Kbps to ~44Kbps,
depending on the quality of the phone
line to your dialup location. Some lines will allow better performance,
some worse.
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Cable
Modem: Typically a
residential connection, that provides high (though variable)
bandwidth to the user. Upload speed us usually restricted to
128Kbps, but download speeds can be up to 2 Mbps. Bandwidth is
dependent on number of users active on the local cable loop
and the capabilities of the network equipment the cable
company uses. Another problem of shared bandwidth is security.
Finally, sevice quality is dependent on the local cable
company.
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DSL or xDSL (Digital
Subscriber Line): This is an all-digital
high-speed connection which is typically always on whenever your
computer is on. No waiting for a dialup modem connection, much
faster than dialup speeds. In most cases, where DSL is available,
this service can be installed over your existing telephone line for
"line sharing" both regular voice and data transmission on the same
line simultaneously. DSL is limited to several thousand wire feet
from a Telco Central Office (CO). Not all residences or businesses
are eligible for DSL because of this restriction. xDSL is an
oft-used term, as DSL comes in several flavors, some of which are
listed below.
ADSL (Asymmetric DSL): This is the standard offering for private residences.
"Asymmetric" means that the download speed is not the same as the
upload (e.g. 768k download and 128k upload). In addition to distance
limitation from the Central office, Distance and physical line
quality will affect actual throughput
speeds.
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