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What is
Networking?
Networking
is a group of computers, printers, and other devices that are connected
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Allows sharing
of one internet connect and one printer between multiple computers.
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Communicate with
the family
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Download music
and video to shared devices in the home
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Play PC games on
your local area network
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More and more
households are using more than one computer. In the United States, about half of
all households have computers, and of these more than 20 million households have
more than one computer! Home networks are becoming increasingly common to
realize the tremendous opportunities sharing computers offers!
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What
is Wireless Networking?
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In a wireless network, all of the computers in your home or office broadcast
their information to one another using radio signals rather then wires. Being
wireless makes it a whole lot simpler to move computers around from one room to
another without having to run new wires. For example, a laptop with a
wireless-network card is completely portable throughout your home or office. |
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How can I Benefit
from having a Wireless Network?
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No need to pay
someone to run expensive cable throughout your home or office.
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Save you the
cost of running new cable each time you want to move your computer.
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There is no need
to buy a printer for each computer, all computers can share one or multiple
printers.
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Enables everyone
to surf the internet, send and receive email all at the same time without
being connected to wires.
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Freedom to be
pool side or on your deck when telecommuting.
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Allows you total
mobility to roam about your home or office and still maintain your internet
connection.
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Below shows a diagram of a wireless network
How
Wireless LANs Are Used in the Real World
The following list describes some of the many applications made possible through
the power and flexibility of wireless LANs:
| Doctors and nurses in
hospitals are more productive because hand-held or notebook computers with
wireless LAN capability deliver patient information instantly. |
| Consulting or accounting audit
teams or small workgroups increase productivity with quick network setup. |
| Students holding class on a
campus green are able to access the Internet to consult the catalog of the
Library of Congress. |
| Network managers in dynamic
environments minimize the overhead caused by moves, extensions to networks,
and other changes with wireless LANs. |
| Training sites at corporations
and students at universities use wireless connectivity to ease access to
information, information exchanges, and learning. |
| Network managers installing
networked computers in older buildings find that wireless LANs are a
cost-effective network infrastructure solution. |
| Trade show and branch office
workers minimize setup requirements by installing pre-configured wireless
LANs needing no local MIS support. |
| Warehouse workers use wireless
LANs to exchange information with central databases, thereby increasing
productivity. |
| Network managers implement
wireless LANs to provide backup for mission-critical applications running on
wired networks. |
| Senior executives in meetings
make quicker decisions because they have real-time information at their
fingertips. |
Once again, wireless LAN users
can access shared information without looking for a place to plug in. Network
managers can set up networks without installing or moving wires. Wireless LANs
offer the following productivity, convenience, and cost advantages over
traditional wired networks:
| Mobility: Wireless LAN systems
can provide LAN users with access to real-time information anywhere in their
organization. This mobility supports productivity and service opportunities
not possible with wired networks. |
| Installation Speed and
Simplicity: Installing a wireless LAN system can be fast and easy and can
eliminate the need to pull cable through walls and ceilings. |
| Installation Flexibility:
Wireless technology allows the network to go where wire cannot go. |
| Reduced Cost-of-Ownership:
While the initial investment required for wireless LAN hardware can be
higher than the cost of wired LAN hardware, overall installation expenses
and life-cycle costs can be significantly lower. Long-term cost benefits are
greatest in dynamic environments requiring frequent moves and changes. |
| Scalability: Wireless LAN
systems can be configured in a variety of topologies to meet the needs of
specific applications and installations. Configurations are easily changed
and range from peer-to-peer networks suitable for a small number of users to
full infrastructure networks of thousands of users that enable roaming over
a broad area. |
Other topics
What is Spread Spectrum
Technology?
Most wireless LAN systems use spread-spectrum technology, a wideband radio
frequency technique developed by the military for use in reliable, secure,
mission-critical communications systems. Spread-spectrum is designed to trade
off bandwidth efficiency for reliability, integrity, and security. In other
words, more bandwidth is consumed than in the case of narrowband transmission,
but the tradeoff produces a signal that is, in effect, louder and thus easier to
detect, provided that the receiver knows the parameters of the spread-spectrum
signal being broadcast. If a receiver is not tuned to the right frequency, a
spread-spectrum signal looks like background noise. There are two types of
spread spectrum radio: frequency hopping and direct sequence.
What is
Frequency-Hopping Spread Spectrum Technology?
Frequency-hopping spread-spectrum (FHSS) uses a narrowband carrier that changes
frequency in a pattern known to both transmitter and receiver. Properly
synchronized, the net effect is to maintain a single logical channel. To an
unintended receiver, FHSS appears to be short-duration impulse noise.
What is Direct-Sequence
Spread Spectrum Technology?
Direct-sequence spread-spectrum (DSSS) generates a redundant bit pattern for
each bit to be transmitted. This bit pattern is called a chip (or chipping
code). The longer the chip, the greater the probability that the original data
can be recovered (and, of course, the more bandwidth required). Even if one or
more bits in the chip are damaged during transmission, statistical techniques
embedded in the radio can recover the original data without the need for
retransmission. To an unintended receiver, DSSS appears as low-power wideband
noise and is rejected (ignored) by most narrowband receivers.
What is Infrared Technology?
A third technology, little used in commercial wireless LANs, is infrared.
Infrared (IR) systems use very high frequencies, just below visible light in the
electromagnetic spectrum, to carry data. Like light, IR cannot penetrate opaque
objects; it is either directed (line-of-sight) or diffuse technology.
Inexpensive directed systems provide very limited range (3 ft) and typically are
used for personal area networks but occasionally are used in specific wireless
LAN applications. High performance directed IR is impractical for mobile users
and is therefore used only to implement fixed sub-networks. Diffuse (or
reflective) IR wireless LAN systems do not require line-of-sight, but cells are
limited to individual rooms. |
