CSCwb13784-APs not able to join 9800invalid path MTU in AP Joinrequest

[cisco.bonn]

my customer has a WLC 9800-40 (17.7.1), which is affected with the mentioned Bug.

An upgrade to his WLC is not an option for him now.

In the release note 17.3.5 there is a hot-patch resolves this problem:

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Known issue: APs are unable to join the controller because of an invalid path MTU in the AP join request (CSCwb13784).

To fix this issue, apply the mandatory patch that has been released for all deployments having an MTU lower than 1500 bytes (for example, CAPWAP over WANs), regardless of the AP type. This recommendation could apply to local network scenarios. This hot patch does not require a controller reload.

The following are the image names for the SMU update:

• C9800-CL-universalk9.17.03.05a.CSCwb13784.SPA.smu.bin

• C9800-L-universalk9_wlc.17.03.05a.CSCwb13784.SPA.smu.bin

• C9800-universalk9_wlc.17.03.05a.CSCwb13784.SPA.smu.bin

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My question is: is it OK to apply this patch to WLC (17.7.1)?

Patch: C9800-universalk9_wlc.17.03.05a.CSCwb13784.SPA.smu.bin

WLC 9800-40 > Version 17.7.1

Thank you

[JPavonM]

No this patch is only to fix a defect on 17.3.5 code not others.

If you have any other MTU related issue in other codes I would recommend you to open a TAC case to investigate.