CAPWAP-3-DATA_KEEPALIVE_ERR: Failed to receive data keep-alive

[ajc]

I checked for another post regarding the use of "_" as AP Group name but that is not our case. I am getting multiple error messages likes this after migration this site from a traditional MPLS connection with guaranteed BW to SD-WAN where the remote gateway is now a FW running an IPSEC tunnel to the HQ with the capwap tunnel travelling inside. We are having

I got this article where it mentions something about MTU and larger packets being dropped so I was wondering if my issue has something to do with this. I am still doing my research, collecting debugs, etc.

https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/211405-Configure-CAPWAP-Path-MTU-Discovery.html

[romain-salmon]

Hello,

Have you found a solution ?

[Rich R]

@romain-salmon probably better to open a new thread.  But either way:
- What model of WLC and APs are you using?
- What version of software are you using?
- What exactly is the problem you are experiencing?

Generically speaking:
- make sure your software is up to date as per TAC recommended link below.  WLC 2504, 5508 or 8510 should be running 8.5.182.12.  WLC 3504, 5520, 8540 should be running 8.10.196.0
- Check your WLC config using Config Analyzer (link below)
- Refer to https://bst.cisco.com/bugsearch/bug/CSCvm76689 and https://bst.cisco.com/bugsearch/bug/CSCvt16235 regarding AP path MTU settings.

[romain-salmon]

Hello thanks for your fast reply.

- What model of WLC and APs are you using?vWLC: 8.10.185.0. AP :  AIR-CAP1702I-E-K9,AIR-CAP2702E-E-K9,AIR-AP1832I-E-K9, AIR-AP2802E-E-K9. But i dunno if i have the problem for all the AP.
- What exactly is the problem you are experiencing?

I have exactly this problem : some joined the WLC then disconnect after 1min. I ll open a TAC case soon

 https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvc42741

[Rich R]

That bug is caused by having a device on the local subnet with an (invalid) IP address the same as the WLC.  Obviously if you have that you should remove it!
In any event that bug was fixed long before 8.10 so it cannot be that particular bug.
Don't waste your time with TAC until you have updated to 8.10.196.0 - that's probably the first thing TAC will tell you to do anyway!
If you still see the problem then get a packet capture on the AP switch port so that you can see exactly what is going on.
Share the complete console log file from the AP from power-on showing all logs up to and including when it starts failing.  Save the logs to a text file (.txt) and attach here.
Also check the WLC logs for any relevant messages.
Check the AP join stats on the WLC showing the disjoin reason.

Since all your AP models are supported on 9800-CL virtualised WLC why are you still using AireOS vWLC which is now effectively end of life?  https://www.cisco.com/c/en/us/products/collateral/wireless/8500-series-wireless-controllers/wireless-software-8-10-pb.html I highly recommend upgrading to IOS-XE based 9800-CL which is still fully supported.  9800 release 17.12.x is the last release to support the 1702 and 2702 APs because they are now End of Support. (which also means that TAC could refuse to troubleshoot any issues with those APs)
https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-12/release-notes/rn-17-12-9800.html#supported-aps