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Wireless connection failure for a specific device.

Hello, this is Cisco Community.

Only certain PDA devices cannot connect wirelessly.
As for the wireless communication specifications of the PDA device, the device supports all 802.11 a/b/g/n/ac.
Additionally, both WPA 1 and 2 PSK are supported in the WLAN Security specifications.

Normal communication is possible when connecting Meraki wirelessly with the corresponding PDA device.
In the same place is a Catalyst 9800 with C9115AXE device for dedicated PDA wireless.
The problem is that there is no connection to C9115AXE.

The C9115AXE wireless connection is established normally with other PDA devices (I understand them to be PDA devices from other manufacturers).

The detailed phenomenon reported is that when you try to connect the PDA SSID, it immediately goes to Connecting > Not Connected.
WLC leaves no logs for the device. (There is no log related to Connection Failed.)

In C9800, the AP Radio Interface is 802.11ax.
When I looked it up, I found that there were no compatibility issues between AX and AC.

Have you ever seen a case like this?
For detailed troubleshooting, it would be a good idea to check packet capture or debug on the AP. What are the related commands?

thank you.

1 Accepted Solution

Accepted Solutions

Confirmed to be a WLC OS bug.
Bug code CSCvu24770
After updating to the latest firmware, the problem disappeared.
Thanks everyone!

View solution in original post

15 Replies 15

Leo Laohoo
Hall of Fame
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What firmware is the controller on?
What is the actual model of the WLC?

Hi Laohoo,

WLC Model = C9800-L-F-K9,

Firmware = 17.03.04c

It has been about 3 months since we built the entire system.


Turn off 802.11ax.  

See if this makes things better.


Thank you for answer.

How do I turn off 802.11ax?

I didn't see it anywhere in the WLAN settings.



Go to the Advanced tab and scroll down to the 11ax section.

Leave "Enable 11ax" un-ticked.

Hall of Fame
Hall of Fame

Not that we heard this behavior.

what IOS XE code running on WLC ?

take one of the PDA and debug the connection issue and you can use troubleshoot WLC debug logs.

check the debug analyzer :




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Hi bandi,

Thanks for your answer.

Since PDA device connection tests are not always performed, it seems that there will be time to extract debug data.

thank you

Since you mentioned only few model having issue, there may be compatible issue due to speed and negotiation, if you do the debug you may notice any information which can help you to fix the issue.

also suggest to upgrade WLC to latest code 17.9.4a or above for lot of bugs and other issues fixed. (if you get chance and downtime).



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   For testing : if you know to which AP a PDA device  will connect (and or in a lab setup) ; issue this command first on the AP:
                          show  ap client-trace events mac aa:bb:cc:01:02:03 (replace MAC with that of the PDA device   ). Then during the connecting process (and later) follow up on the outputs shown or check the logs on the AP.

                  - 17.3.x is getting old and or EOL ; go for 17.9.5


-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

Hi Marce1000, I tried to check the MAC address of the PDA using this command, but no information was displayed.
The event on the test laptop has been confirmed.
If no event is displayed, can I understand that the PDA did not send any packets/data to the AP?

The PDA's OS uses Android 10.

thank you