How do I configure a WLAN?

The first step in configuring a WLAN is to ensure that all wireless network cards have the correct drivers installed. For an ad-hoc connection between computers (without an access point), the computers need to be set to operate in ad-hoc mode using the wireless configuration utility. In Windows XP, wireless configuration is automated by the Zero Wireless Configuration service, but other operating systems will require the WNIC configuration utility that came with the device.

Secondly, a name or SSID needs to be assigned to the WLAN. This is the station ID, and it performs the same function in the wireless network that a workgroup name does on a regular Windows LAN. For devices to communicate, they must connect to the same SSID. Alternatively, the devices can be set to connect to any available wireless connection. To enable data encryption, WEP should be turned on and a password entered. In Windows XP, the password can be 5 orto 13 characters long or a hexadecimal string.

For an example of a network status box, click here.

The process is similar when configuring a WLAN in "infrastructure" mode, which simply means that an access point is incorporated, usually as a gateway to a LAN. Most access points can be configured using any PC on the LAN they are connected to. This can be via a Web interface or standard desktop application. The access point, like a WNIC, must be assigned the same SSID or network name, along with the password for WEP encryption.

Here's an example of how to configure an access point.

What are the operating system requirements?

As mentioned previously, wireless networking is integrated into Windows XP - both Home and Professional versions. For other operating systems the only requirement is that the WNIC used has compatible drivers and a configuration utility. If you plan to use a USB wireless adaptor, make sure you have at least one USB port available and the latest drivers installed for your motherboard and/or USB PCI card.

Ad-hoc vs infrastructure networking

Ad-hoc Networking

Two or more PCs with wireless network cards can be configured to form what is referred to as an ad-hoc wireless network. Simply set all the network cards to connect to the same wireless workgroup name (SSID) and to use ad-hoc mode. In Windows XP this is done using the network properties for the wireless network card. Other operating systems will require the configuration utility that came with the card.

Infrastructure Networking

To connect one or more wireless PCs to an existing wired network, a wireless access point is needed. Sometimes these devices combine a router and an ADSL modem, making them ideal for Internet connection sharing. Simply plug the access point into the Ethernet hub and configure it with the utility supplied by the vendor. Assign it a wireless workgroup name (SSID) and use this name when configuring the wireless PCs to run in infrastructure mode.

The difference between an ad-hoc and infrastructure-based network is shown in this diagram.