An understanding of wireless LAN (WLAN) client and WLAN access point (AP) communication mechanisms is critical to anyone attempting to initially connect or troubleshoot a WLAN connection. In this article, I discuss how to troubleshoot WLAN client connectivity issues.
There are several features of the WLAN client that require configuration in order to connect to a wireless AP and to transmit data. These can include SSID, IP addressing, security and channel configuration parameters. Basically, the WLAN client configuration will have to meet the configuration that has been set up on the AP. In most cases, an admin configuring a WLAN for office users or the user setting up a WLAN in a home office will be configuring the access point and can therefore match the client configuration settings and AP settings easily. However, most of the WLAN client issues I see relate to users who have new WLAN cards or embedded WLAN cards.
Configuration parameters
As I said above, in order to connect to an AP, the client and AP must match in their configuration. The first thing that you want to ensure is that the client is configured properly. The following are the basic configuration parameters that must be met:
Troubleshooting the client
Once you have looked at all the areas that need to be configured, the real focus is how you configure/troubleshoot the client. Let's consider the client device for a minute. If you are the person who installs the WLAN card, make sure that you install the GUI capabilities of the WLAN card. This is basically a front end that allows you to view available WLAN networks and configure the information on them. In most cases, the GUI will show available networks (the actual SSID) and the channels that they are broadcasting. Just double-click the available network and see whether your card connects. If there is a symbol beside the network name that looks like a lock, it means the AP is configured with security mechanisms and yo
To continue reading for free, register below or login
To read more you must become a member of SearchNetworking.com
u will have to get this information from the AP administrator to connect. Once connected (the GUI will show that you are connected) you can ascertain whether or not you have been assigned an IP address by doing the following:
This is really straightforward. However, many new laptops are shipping with Intel Centrino Mobile network adapters already installed in the laptop. This means that you did not install a WLAN card, it was just there. The only way to configure the embedded WLAN card is via the Windows software installed on your PC. Windows software will walk you through the setup and configuration of the WLAN card, but I can attest from experience that it is really confusing. In addition, if you have to modify these settings, it can be very cumbersome. Therefore, the recommendation is to download and install the drivers that include the GUI for the embedded Centrino WLAN NIC. Here is how that is done:
There are several different network connections you may be able to see. One may be a LAN connection, but what you are looking for is the WLAN connection. The screen will show the connection name, type, status, device name, or some variation of these. The key information is the device name. On my Dell laptop, I have the Intel PRO/Wireless 2915ABG network connection. When I first got my new laptop, I could not configure this adapter, so I downloaded the drivers from Dell and installed them. Now I have a GUI and do not have to utilize Microsoft's mechanisms for configuring the adapter.
There are several ways to get the drivers. You can do a search on Google for the driver (I did this and got Intel driver information) or you can go to the laptop vendor's support page, browse to "drivers," and find the driver for your laptop. You will need the laptop model number to do this, and I recommend this path to ensure that the drivers are compatible.
That's it. Installing the GUI and knowing how to validate and configure the SSID, channel, security and IP address settings will solve 99% of the client issues associated with WLAN connectivity. Most of the other issues are related to performance of the RF environment and the back-end infrastructure supporting the WLAN network, all of which cannot be addressed by the end user.
Robbie Harrell (CCIE#3873) is the National Practice Lead for Advanced Infrastructure Solutions for SBC Communications. He has more than 10 years of experience providing strategic, business and technical consulting services. Robbie lives in Atlanta and is a graduate of Clemson University. His background includes positions as a Principal Architect at International Network Services, Lucent, Frontway and Callisma.
