WLAN Wireless Networking

by Johannes Helmig [Published on 31 Aug. 2002 / Last Updated on 31 Aug. 2002]

In the last years, a new technology has become available, avoiding the need for network cables:

WLAN : Wireless networking

WLAN allows you at home to share an Internet connection in all rooms,
without having to drill holes and put in Network cables between all
the room.
In such cases, you would use a WLAN Router, often available as
combination unit of WLAN-router and DSL / ADSL modem.
using a Wireless Access-point,
networks can be configured with
systems connected via cables and
via Wireless connections.

Such wireless connections are
often used in offices, where users
with notebooks need to be able
to move between different rooms
and need to continue to be connected
to the network without having the
need to re-connect to a network
cable (for example: in conference rooms).

Like networking via coax-cable (10base2) or via coax-cables (10baseT / 100baseT / 1000baseT),
WLAN networking is a world-wide standard :

802.11b : maximum bandwidth : 11 Mbps
802.11g : maximum bandwidth : 54 Mbps

Most 802.11g installations allow dual-speed operations, allowing wireless connection of
802.11b - 11Mbps clients and of 802.11g - 54 Mbps clients.

At this time ( Sept.2003), 802.11g devices are still more expensive than 802.11b devices,
so which one should you buy ?
- for home to share an Internet connection : 802.11b is sufficient, since it is still faster than
most cable-modems or DSL/ADSL connection.
- for office use, where you need to copy via the network large files, use 802.11g.

Range:
Depending on the WLAN devices and where it is used (outside or in a building with walls),
you can have a wireless connection between 50 meter (side a building through walls and floors)
and 500 m (outside with no items between Access Point and client).


for WLAN, the following components are available:

WLAN Access-point :
Allows multiple systems with WLAN network cards to
connect to the network, for communication with other
wireless systems and/or systems connected via network cables
( like a network hub, but using wireless communication instead of cables)
WLAN Network Interface card
for installation in a desk-top PC
WLAN PC-Card / PCMCIA Card
for installation in a notebook computer
WLAN via USB
for connection via a USB port (in case that you do not like
to open a desktop PC or that the PC-card / PCMCIA slot
of a notebook are already filled with other devices.

Configuration of WLAN devices:

A proper configuration of WLAN devices is important to make sure that you have a secure network:

when using network cables, a stranger would have to connect via a network cable.
But now you are using a wireless connection : a strange can sit outside in a car or in a park
with a notebook can connect to your system.

And this is not a joke:
several tests have been made in large cities, where people were driving in a car through
business areas and they did find a lot of WLAN networks, where they could connect!

The main reason for this:
to make is easy for users to establish a first WLAN connection ( to avoid to get a lot
of support calls), most WLAN access-points are shipped with a default configuration,
allowing easy access with minimum need for configuration.
but if you can connect so easy to a WLAN, so can unwanted guests !


- Example for an Access Point configuration
- Example of a PC-Card configuration / connection to the Access-Point

Warning :
using default values of a WLAN Access-point create unsecure networks !


I have seen several articles in computer journals, where they went in a car through a business
district and could locate and connect to multiple WLAN network, connecting to company
networks!

Have you ever seen signs like these on walls ?

They indicate WLANs and define the SSID !

for more information on these symbols :
www.warchalking.org


It is a MUST to use the security features of the WLAN Access-Point !

- Example to secure your WLAN

In general. WLAN network cards are supported for all versions of Windows , as long as the
supplier of the WLAN network card is delivering the required software driver for it.

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