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5/3/2002
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wireless networking
Wireless Networking Using 802.11b
To form a wireless network, two basic components are used. The first is a
wireless adapter for a PC. This can be either a USB wireless adapter or a
PCMCIA adapter. The adapter gives the PC wireless Ethernet capabilities.
The second is a wireless access point, which can connect to a wired LAN
and allow the wireless PCs to be able to access the wired LAN. A wireless
access point can be a stand-alone component or it can be embedded into
a cable/DSL router, thus forming a wireless gateway router. The use of
each of these types of products is outlined later in this article.
Wireless networking is very similar to wired networking, except for a
few basic concepts that one must grasp. There are two different ways
to network computers using 802.11b. The first, and least used method is
the "Ad-Hoc" method, also known as "Peer-to-Peer". The more commonly
used method is called "Infrastructure" mode.
Peer-to-Peer (Ad-Hoc) Network
Ad-Hoc, or Peer-to-Peer, refers to a wireless configuration in which each
computer communicates directly with another. An Ad-Hoc wireless network
(LAN) consists of a group of computers, each equipped with a wireless
adapter, connected directly via radio signals to form an independent
wireless LAN. Computers in a specific Ad-Hoc wireless LAN must be
configured to the same radio channel and network name to communicate
with one another. More than one Ad-Hoc network can exist in the same
space if it is configured to operate on a different channel. There are a
varying number of channels depending on which part of the world you are
operating in. The US has 11 channels, Europe has 13 channels, and Japan
has 14 channels. The following diagram shows a typical Ad-Hoc wireless
LAN configuration.
Notebook with Wireless
Notebook Network Card
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Notebook with Wireless
Notebook Network Card
PC with Wireless Desktop
PCI Network Adapter
wireless networking
Infrastructure Network (Access Point)
The use of a wireless access point to connect a wireless LAN to a wired
LAN is called Infrastructure mode. A wireless access point serves as a
bridge between the wired and wireless network. Connecting the access
point to any port on the wired network will give wireless access to all
wireless-equipped computers within its coverage area. An access point
is configured with a "Service Set Identifier (SSID)", a "name" given to
the wireless network and used by the wireless-equipped computers to
access the wireless network. Access points can also be configured to use
encryption or they can grant access to computers with specific MAC
addresses. They effectively double the distance that computers in the
wireless LAN can be located from one another. This is because the unit
serves as a central point for routing of all the wireless network traffic
between the wireless-equipped computers. Wireless-equipped computers
networked together in Infrastructure mode form a group called a "Basic
Service Set (BSS)". Up to 64 individual computers can exist at a single
time in a BSS. This is due to the ability of the wireless access point to
handle no more than 64 clients. The diagram below illustrates how the
wireless access point works to increase the covered area range of your
wireless network.
Notebook with Wireless
Notebook Network Card
WAP
Basic Service
Set (BSS)
Notebook with Wireless
Notebook Network Card
PC with Wireless Desktop
PCI Network Adapter
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