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Wireless Ethernet Networking
with 802.11b
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| In 2000, 802.11b became the standard wireless
ethernet networking technology for both business and home. The WiFI
organization was created to ensure interoperability between 802.11b
products. With a realistic throughput of 9.5-11Mbps, it is fast enough
for most network applications and tolerable for file transfers. |
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Do I need an access point? |
| An 802.11b wireless network adapter can operate
in two modes, Ad-Hoc and Infrastructure. In infrastructure mode(AP),
all your traffic passes through a wireless ‘access point’. In Ad-hoc
(peer) mode your computers talk directly to each other and do not
need an access point at all. |
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Access point varieties |
| Access points come in three varieties -- bridge,
NAT router and NAT router+bridge. A bridge type connects a wireless
network to a wired network transparently. Communication is possible
between both networks in both directions. A NAT router type routes
traffic from your wireless network to an Ethernet wired network, but
it will not route traffic back. This type can be used to share an
Internet connection. Lastly, there are hybrid NAT router + Bridge
devices that bridge your wired and wireless networks, then route them
both to the internet using a single IP address. This is good for sharing
an Internet connection when you have both wired and wireless computers
in your home. These are often called Cable/dsl routers with wireless
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Bridge Access Point Diagram |
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NAT Router Access Point Diagram |
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Cable/DSL Router with Wireless Ethernet
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Security |
| Any network adapter coming within range of another
802.11b network adapter or access point can instantly connect and
join the network unless WEP – wireless encryption protocol – is enabled.
WEP is not very secure, although it's better than nothing. There are
several flaws in WEP making it unusable for high security applications.
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WEP and Speed |
| WEP ‘WILL’ slow down your wireless network. Expect
a 20-50% reduction in speed depending on the products you are using.
The speed issue is often the result of an access point without enough
processing power. |
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Encryption keys |
| Encryption comes in 64bit and 128bit key varieties.
All your nodes must be at the same encryption level with the same
key to operate. 40bit and 64bit encryption is the same thing, it’s
just a matter of how the manufacturer decided to label the product.
Often 128bit cards can often be placed in 40/64bit mode. |
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NIC Form Factors |
| 802.11b adapters come in two major form factors.
PCCards for laptops and USB for desktops. In addition, there are PCI
adapters that let you plug a PCCard into a PCI Slot. PCI slot adapters
are often finicky about working correctly in anything but Windows
98/SE/ME. I would opt for the USB version to play it safe if you have
Windows XP or 2000 on a desktop machine. |
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How fast is it (real world)? |
| A full strength 802.11b signal will get you about
9.5-11 Mbps without WEP enabled. With WEP enabled, expect 5.5-9.5
Mbps. As you put walls and distance between your wireless adapter
and your access point, your speed will drop. Don’t expect to put more
than a few walls between you and your access point. |
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Technical: |
| 802.11b is a half duplex protocol – it can send
OR revive, but not both at the same time. In addition it uses the
same 2.4 GHz range as many cordless phones so plenty of opportunity
exists for interference. Use 900Mhz cordless phones if using 802.11b
in the same area. |
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Extended range? |
| Some people have used directional
antennas to get some serious range out of their 802.11b products –
miles! Some others use antennas to find and compromise networks like
yours. |
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