I have deployed a WLC4404-100 running software version 22.214.171.124. Lightweight APs (model: LAP1242AG-C-K9) in an office building join to this controller via Layer 3 LWAPP transport mode. Few WLANs (SSIDs) are created with different security policies.
The APs are initially installed with 2.4GHz antennas (AIR-ANT4941) to enable 802.11b/g network and everything works fine.
Recently I installed 5GHz antennas (AIR-ANT5135D-R) on few of the APs to enable 802.11a network and used a Dell Latitude D620 notebook (with built-in Intel PRO 3845ABG radio card) to test.
The laptop is able to automatically associate to two of the SSIDs (WPA1+WPA2 with 802.1x and Web Authentication with Static WEP) using 802.11a standard. Strangely, it never able to associate using 802.11a to the other SSID which is configured for dynamic WEP with 802.1x. It always associated using 802.11g.
Eventho I disabled 802.11b/g radio on that floor's APs, the laptop roams to another floor's AP using 802.11g standard.
I can't explain why the laptop is able to associate to two of the SSIDs using 802.11a and not to the third SSID. Is there any dependency between SSIDs and the physical standards?