Cisco Aironet Wireless LAN Client Adapters

Cisco Aironet 802.11 A/B/G Client Adapters CB21AG & PI21AG

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The following information details the new features, changed specifications, and closed caveats for the Desktop Utility Installer 4.0 release of the Cisco® Aironet® Client Adapters, CardBus (CB21AG), or PCI (PI21AG).

New Features

The Desktop Utility (ADU) version 4.0 release enhances Cisco's secure wireless solution with the addition of version 5.0 of Cisco Client Extensions (CCX).
Cisco Client Extensions (CCX) v5.0 including the following highlights:

Client troubleshooting, diagnostics, and reporting

The capability to more quickly diagnose network access problems can reduce the total cost of ownership of a wireless local area network. The diagnostic features enable an end-to-end troubleshooting capability within Cisco's wireless LAN infrastructure. The network managed test feature in the diagnostics tab of the ADU requires software release 4.2 on Cisco's Wireless LAN Controller.

Management Frame Protection

Management Frame Protection (MFP) enables a more secure wireless solution by encrypting management frames sent between the client and the wireless LAN. Management frame protection requires software release 4.1.181 or later on Cisco's Wireless LAN Controller.

Table 1. Resolved Caveats



CSCsf96751-CB21AG client does not function properly with PC network bridge feature

Network bridging on a PC with the CB21AG client and a wired NIC initially allows traffic to pass from end to end. However, if the PC is rebooted, the network bridge does not start because the CB21AG does not associate to the access point.

CSCsg65164-Authentication timeout for EAP-FAST occurs after 60 seconds

The ADU sends an EAPOL-start message after 30 seconds. However, the login window does not appear. The ADU sends a second EAPOL-start message after 30 seconds. After this second message, the login window appears. It takes 60 seconds for the login window to appear, even when the Authentication Timeout Value is set to 30 seconds.

CSCsg99350-CB21AG client does not follow data-rate setting on WLC

The CB21AG client does not follow the data-rate setting on the WLC. The client uses the 1-Mbps and 2-Mbps data rate for 802.11 data packets even though these rates were disabled on the WLC. This caveat was changed to an enhancement request.

CSCsh49433-CB21AG fails to associate at extended channel set for (-KE) domain

CB21AG and PI21AG fail to associate at extended channels for 802.11A other than channels 149, 153, 157, and 161 in (-KE) country code setting for 4404 controller.

CSCsi11587-CCKM caching and roaming are not working with WLC

When the client first authenticates to AP1 and then to AP2 in roaming, there is packet loss when pinging. User credentials are not cached.

CSCsi49993-AP scan log timer at 0 seconds freezes CASSU and CPU usage reaches 100 percent

When the access point scan list logging timer is set to 0 seconds in the CASSU AP Scan List Logging Configuration window, the CASSU stops responding and CPU usage reaches 100 percent.

CSCsj27353-CB21AG does not work with 802.11a channel 52, 56, 60, and 64 on WLC AU

Wireless clients in Australia cannot associate with 802.11a access points. The 802.11a mid-band (5.4-5.725) is not working. The other two bands are working with the CB21AG and other vendors. Wireless clients can connect on channels 36, 40, 44, 48, 149, 153, 157, 161, and 165 but cannot connect on channels 52, 56, 60, and 64.

CSCsk29290-MAC address returned during manufacturer information test in S65 is incorrect.

Manufacturer's information was incorrect in the S65 message.

Upgrade Paths

The version 4.0 Cisco Aironet CardBus CB21AG and PCI PI21AG client adapter software is incompatible with other Cisco Aironet Client Adapter Software. The Desktop Utility Installer 4.0 release is an upgrade for prior software releases of the Cardbus CB21AG and PCI PI21AG adapters.


The Cisco Aironet 802.11 a/b/g Client Adapter Desktop Utility Installer 4.0 release became available for purchase on October 12, 2007.

Ordering Information

The Cisco Aironet 802.11 a/b/g Desktop Utility Installer 4.0 release is available for download through the Cisco download center. From the main page on, go to the Cisco Ordering page. To download software, visit the Cisco Software Center.

Table 2. Ordering Information

Product Name

Download File

Cisco Aironet 802.11 a/b/g CardBus Wireless LAN Client Adapter Desktop Utility Installer 4.0 (CB21AG)


Cisco Aironet 802.11 a/b/g PCI Wireless LAN Client Adapter Desktop Utility Installer 4.0 (PI21AG)


Service and Support

Obtaining Technical Assistance

Cisco Technical Support provides 24-hour-a-day award-winning technical assistance. The Cisco Support Website on features extensive online support resources. In addition, if you have a valid Cisco service contract, Cisco Technical Assistance Center (TAC) engineers provide telephone support. If you do not have a valid Cisco service contract, contact your reseller

Cisco Support Website

The Cisco Support Website provides online documents and tools for troubleshooting and resolving technical issues with Cisco products and technologies. The Website is available 24 hours a day at:
Access to all tools on the Cisco Support Website requires a user ID and password. If you have a valid service contract but do not have a user ID or password, you can register at:

For More Information

For more information about the Cisco Aironet 802.11 a/b/g client adapters (CB21AG and PI21AG), visit: