If you want to have a network in your home or office, you can
connect the computers together using a wireless network also
known as 802.11 networking and WiFi. (Wireless Fidelity). You
can connect computers anywhere in your home or office without
the need for wires. The computers connect to the network using
radio signals, and computers can be up to 100 feet or so apart.
Wi-Fi (Wireless Fidelity) is a logo and term given to any IEEE
802.11 wireless network product that is certified to conform to
specific interoperability standards. Wi-Fi Certification comes
from the Wi-Fi Alliance, a nonprofit international trade
organization that tests 802.11-based wireless equipment to
ensure it meets the Wi-Fi standard. To wear the Wi-Fi logo, an
802.11 networking product must pass specific compatibility and
performance tests, which ensure that the product will work with
all other manufacturers’ Wi-Fi equipment on the market. This
certification arose from the fact that certain ambiguities in
the 802.11 standards allowed for potential problems with
interoperability between devices. By purchasing only devices
bearing the Wi-Fi logo, you ensure that they will work together
and not fall into loopholes in the standards. The most common
forms of wireless networking in the United States and Canada are
built around various versions of the IEEE 802.11 wireless
Ethernet standards, including IEEE 802.11b, IEEE 802.11a, and
the newer IEEE 802.11g standard. In Europe, HiperLAN, which has
performance and frequency usage similar to that of 802.11a, is
the wireless networking standard. In the past, Wi-Fi has been
used as a synonym for IEEE 802.11b hardware. Because the Wi-Fi
Alliance now certifies other types of 802.11 wireless networks,
the term Wi-Fi should always be accompanied by the frequency
band (as in Wi-Fi 2.4GHz band) to make it clear which products
will work with the device. The new 802.11g wireless standard has
the speed of 802.11a, but connects to 802.11b networks without
special hardware. As 802.11g hardware passes Wi-Fi Alliance
tests, it will also be known as Wi-Fi-compliant hardware.Here it
is a table of 802.11-compliant networks: Table 20.9. IEEE
802.11-Based Wireless Networks IEEE Standard Maximum Speed Wi-Fi
Alliance Term Number of Nonoverlapping Channels Also Known As
Notes 802.11a 54Mbps 5GHz band 12 Wireless-A Dual-band hardware
needed to connect with 802.11b 802.11b 11Mbps 2.4GHz band 3
Wireless-B Can connect with 802.11g; dual-band hardware needed
to connect with 802.11b 802.11g 54Mbps 2.4GHz band 3 Wireless-G
Can connect with IEEE 802.11b; dual-band hardware needed to
connect with 802.11a
802.11 Network Hardware All types of 802.11 wireless networks
have two basic components: * Access points * NICs equipped with
radio transceivers An access point is a bookend-size device that
uses an RJ-45 port to attach to a 10BASE-T or 10/100 Ethernet
network (if desired) and contains a radio transceiver,
encryption, and communications software. It translates
conventional Ethernet signals into wireless Ethernet signals it
broadcasts to wireless NICs on the network and performs the same
role in reverse to transfer signals from wireless NICs to the
conventional Ethernet network Access points are not necessary
for direct peer-to-peer networking (also called ad hoc mode),
but they are required for a shared Internet connection or a
connection with another network. When access points are used,
the network is operating in the infrastructure mode.Some access
points can communicate directly with each other via radio waves,
enabling you to create a wireless backbone that can cover a wide
area, such as a warehouse, without the need to run any network
cabling. NICs equipped for wireless Ethernet communications have
a fixed or detachable radio antenna in place of the usual
coaxial or RJ-45 port or dongle. Adding WiFi to a Computer One
of the best things about WiFi is how simple it is. Many new
laptops already come with a WiFi card built in — in many cases
you don’t have to do anything to start using WiFi. It is also
easy to add a WiFi card to an older laptop or a desktop PC.
Here’s what you do: * Buy a 802.11a, 802.11b or 802.11g network
card. 802.11g has the advantage of higher speeds and good
interoperability on 802.11b equipment. o For a laptop, this card
will normally be a PCMCIA card that you slide into a PCMCIA slot
on your laptop. Or you can buy a small external adapter and plug
it into a USB port. o For a desktop machine, you can buy a PCI
card that you install inside the machine, or a small external
adapter that you connect to the computer with a USB cable. *
Install the card * Install the drivers for the card * Find an
802.11 hotspot * Access the hotspot. A hotspot it is a acces
point. There are many WiFi hotspots now available in public
places like restaurants, hotels, libraries and airports. WiFi
Security Because wireless networks can be accessed by anyone
with a compatible NIC most models of NICs and access points
provide for encryption options. Some devices with this feature
enable you to set a security code known as an SSID on the
wireless devices on your network. This seven-digit code prevents
unauthorized users from sneaking onto your network and acts as
an additional layer of security along with your normal network
authentication methods, such as user passwords. Others use a
list of authorized MAC numbers (each NIC has a unique MAC) to
limit access to authorized devices only. All Wi-Fi products
support at least 40-bit encryption through the wired equivalent
privacy (WEP) specification, but the minimum standard on recent
products is 64-bit WEP encryption. Many vendors offer 128-bit or
256-bit encryption on some of their products. Unfortunately, the
WEP specification has been shown to be notoriously insecure
against determined hacking.For that reason, many network
products introduced in 2003 and beyond now incorporate a new
security standard known as Wi-Fi Protected Access (WPA). WPA is
derived from the developing IEEE 802.11i security standard.
WPA-enabled hardware works with existing WEP-compliant devices,
and software upgrades might be available for existing devices.
You should match the encryption level and encryption type used
on both the access points and the NICs for best security.
Remember: If some of your network supports WPA but other parts
support only WEP, your network must use the lesser of the two
security standards (WEP). http://www.jaec.info
About the author:
Masterand – ” STIC University” , Faculty of Electrical
Engineering and Computer Science, Specialization Software
Engineering web:www.jaec.info