For a while now, I've been using an AirPort Extreme wireless network in my home office. However, due to the limited coverage of the wireless network, I had difficulty getting a wireless connection in my bedroom (My AirPort Extreme base station is in the study). With the kitchen separating the two rooms, I had moderate coverage in the kitchen but I also wanted the ability to surf the Web on my bed using my notebook. So I visited the nearest Apple Center and bought an AirPort Express to extend the range of my network (see Figure 1).
 Figure 1. The AirPort Extreme base station and the AirPort Express. |
In this article, I'll show you the steps you need to perform to extend your AirPort wireless network using the Wireless Distribution System (WDS) feature found in Apple’s AirPort base stations.
Note that you cannot use WDS if you use WPA on your wireless network; only WEP is currently supported.
Here is what my wireless network looks like (see Figure 2):
 Figure 2. My AirPort wireless network. |
The easiest and fastest way to set up your AirPort Express is to use the AirPort Express Assistant application included on the CD that comes with your AirPort Express (see Figure 3).
 Figure 3. Using the AirPort Express Assistant to configure the AirPort Express. |
The first step is to select whether you are creating a new wireless network or extending the range of a wireless network. For my case, I chose “Connect to my current wireless network” and check the “Extend the range of my AirPort wireless network” (see Figure 4) option.
 Figure 4. Extending the range of my wireless network. |
The AirPort Express Assistant will then proceed to detect any available AirPort Express adapter. Once it is found, click on Continue (see Figure 5).
 Figure 5. Detecting AirPort Express. |
You now choose the current wireless network to extend. In my case, my current wireless network name is called AirPortExtreme. Also, you need to assign a name to your AirPort Express for identification (see Figure 6). Since I am placing my AirPort Express in the kitchen, I have named it “Kitchen.”
 Figure 6. Choosing which wireless network to extend. |
If your wireless is protected with WEP, the AirPort Express Assistant will prompt you for permission to retrieve the WEP key from Keychain, if you store it there (see Figure 7).
 Figure 7. Retrieving the WEP key for the wireless network. |
You will then be asked to identify the base station for your current wireless network (see Figure 8).
 Figure 8. Identifying the AirPort Extreme base station. |
Enter the password for the AirPort Extreme base station (see Figure 9).
 Figure 9. Entering the password for the AirPort Extreme base station. |
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Finally, the AirPort Express Assistant will automatically configure the base station to use the new AirPort Express to extend its range (see Figure 10).
 Figure 10. Completing the configuration. |
That’s it! After a brief restart, the AirPort Express should display a green light (see Figure 11) and you are now ready to go!
 Figure 11. AirPort Express ready to go! |
AirPort Express functionality is transparent to the user – the wireless network names of both the AirPort Extreme and AirPort Express are identical.
If you are the adventurous sort who wants to understand what goes on behind the scene, however, you can examine the various settings set by the AirPort Express Assistant using the AirPort Admin Utility application (located in the Applications/Utilities folder).
If you have configured the AirPort Express as explained in the previous section, you should now be able to see the two base stations as displayed in AirPort Admin Utility (see Figure 12).
 Figure 12. Using the AirPort Admin Utility program. |
Let’s first examine the Base Station (10.0.1.1). This Base Station is the AirPort Extreme base station connected directly to my cable modem. Notice that in the WDS (Wireless Distribution System) tab, the option “Enable this base station as a WDS” is checked and the “main base station” option is selected (see Figure 13). This enables the AirPort Extreme base station as a main base station for other remote base stations.
Basically, there are three options available for WDS:
Since I also want my wireless clients to be able to connect wirelessly to my AirPort Extreme base station, the “Allow wireless clients on this base station” is checked.
To add more remote base stations, you can click on the “+” button. The MAC address (00:11:24:08:af:e9) shown in Figure 13 is the MAC address of my AirPort Express.
 Figure 13. Configuring the AirPort Extreme base station as a main base station. |
On the AirPort Express (10.0.1.232), you’ll notice that under the Internet tab, the “Connect using” option is set to AirPort (WDS). The MAC address (00:03:93:ef:29:be) specified is the MAC address of the AirPort Extreme base station. You also need to configure the IP address of the AirPort Express, either manually or by DHCP (see Figure 14).
 Figure 14. Configuring the AirPort Express for WDS. |
Under the Network tab, notice that for wireless network extensions, you have to uncheck the “Distribute IP addresses” option (see Figure 15).
 Figure 15. Disabling DHCP for the AirPort Express. |
Finally, in the WDS tab, select the “remote base station” selection for the “Enable this base station as a WDS” checkbox (see Figure 16).
 Figure 16. Configuring the AirPort Express for WDS. |
The AirPort Express is a cost-effective way to extend the range of your wireless network. While Apple claimed that the AirPort Express’s WDS is only compatible with an AirPort wireless network, there have been reports of successes with non-AirPort wireless network. For now, I am just happy that I am able to access the Web in my bedroom!
Wei-Meng Lee (Microsoft MVP) http://weimenglee.blogspot.com is a technologist and founder of Developer Learning Solutions http://www.developerlearningsolutions.com, a technology company specializing in hands-on training on the latest Microsoft technologies.
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