What to do when having client connectivity issue with OTA enabled
Environment- This article is applicable to controllers running 6.x code and OTA enabled in ARM
Answer- When ARM Over The Air is enabled, the Aruba AP will send OTA updates that are Aruba proprietary packets which can only be interpreted by Aruba AP's and will be bogus frames for other clients or devices.
We have seen issues with some older model WLAN NICs that shut down when receiving OTA management frames from the AP. It would be intermittent and were fixed after disabling scanning or OTA. Mostly these issues seems to be client-specific issue.
WLAN NICs which are older might not handle OTA frames which will be "unrecognized frames" correctly. Ideally, these clients should IGNORE these frames and carry on, but it results in connection drop. Disabling ARM OTA updates will not have much of a negative impact as “PASSIVE SCANNING” would still work and will help AP's discover each other.
To debug this further we would need Air packet capture with and without OTA
1. 3rd party sniffer captures (if this is not possible please take AP packet captures from a nearby AP that can listen to AP and client)
2. pktlogs (plog.bin) - 3 instances (steps given below)
3. AP uplink captures (on AP's ethernet port)
4. ap tech-support logs - 3 instances
On the AP console
echo 3000000 > /proc/sys/ath_pktlog/system/size
2. echo 15 > /proc/sys/ath_pktlog/system/enable
3. Run the test and when the issue is happening
4. cat /proc/ath_pktlog/system > plog.bin
5. Then tftp it to the local machine to save it
Contact Aruba TAC for further analysis with the captured data
Related Links- https://arubanetworkskb.secure.force.com/pkb/articles/HowTo/How-does-ARM-OTA-update-work-How-is-this-configured-via-CLI-and-GUI