Aironet 2800 duplex mismatch

[bvj197222]

Our switch, WS-C3750X-24P running 15.0(2)SE4, keeps Reporting Duplex mixmatch With most of Our 2800 AP's;

Mar 14 09:32:18.338: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet1/0/14 (not half duplex), with XXX_AP3 GigabitEthernet0 (half duplex).
Mar 14 09:32:21.786: %CDP-4-DUPLEX_MISMATCH: duplex mismatch discovered on GigabitEthernet2/0/16 (not half duplex), with XXX_AP6 GigabitEthernet0 (half duplex).

The WLC (Cisco 5508, sw 8.3.140.0) reports speed 1000 and Duplex full. The switch also reports a-full and a-1000 on the switchports. I can only assume that this is a bug somewhere..

[powys]

We're getting this on both Catalyst and Small Business switches, the WLC is running 8.3.143.0. Upgrading to 8.5.x would involve a lot of work as we still have older APs which are supported on 8.3.x but not 8.5.x.

[patoberli]

This is a known issue with 8.3.143.0. See here for more information:
https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html#anc9
It's this bug: https://tools.cisco.com/bugsearch/bug/CSCvi02106
Field notice: https://www.cisco.com/c/en/us/support/docs/field-notices/702/fn70252.html
You can either open a TAC and you get a new 8.3.14x.x image where this is fixed, or wait until the next normal 8.3 release is out.
Please note, it's just a cosmetical issue and the AP/Switch is working correctly.

[David Ritter]

moved to 8.5.140.0 and all is well
Thank you

[wlcuser]

Same phenomenon with Aironet 2800 and WLC SW 8.5.160 on Catalyst 2960X

[patoberli]

Then it should be a different bug. Please open a new thread and include the error messages you see and also the configuration of the switchport plus software version of the switch.

[wlcuser]

Ok i will open a new thread

[wlcuser]

Here´s the new thread:
https://community.cisco.com/t5/wireless-and-mobility/aironet-2800-duplex-mismatch-on-wlc-5520-with-8-5-160-and-c2960x/m-p/4030817#M114544

[Leo Laohoo]

I agree with Patrick.
If the controller is running 8.5MR6 and this message is still appearing, contact Cisco TAC as this could be a new bug.

[ittechk4u1]

I am using 8.5.151.0 and having same issue with one 2802 AP.

[wlcuser]

That is not possible, the problem was temporary and has now gone and is not reproducible, i had running 40 2802I temporary for an event and the issue was only on one port of an 2960X.

The AP´s were deployed to six 2960X but the issue was on only one port of an 2960X although all switchports and all AP´s had the same identical configuration.

[zumriatha]

Hi,

Same issue with 8.3.143.0

Any luck with this ?

[patoberli]

Duplex mismatch is supposed to be fixed in 8.3.150.0:

https://www.cisco.com/c/en/us/td/docs/wireless/controller/release/notes/crn83mr5.html

[Leo Laohoo]

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@zumriatha wrote:

Same issue with 8.3.143.0

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8.3.143.0 was released on 05 June 2018.

The fix is found in release 8.5.151.0 which was released back in 20 June 2019. 

Try upgrading the firmware of the controller.