When reading again, the message "Enabled radar detection on channel" may even be the result of the AP reboot, as a DFS event should generate an event like 'radar detected' or so. Can you check the reboot reason for the AP? ( show ap debug log ap-name xxxxx | inc boot )
If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check
for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
Original Message:
Sent: Jul 31, 2023 06:14 AM
From: AdamNewsonCU
Subject: 5GHZ DFS behaviour on 3xx series APs
Thanks both.
The log messages do seem to only occur on those two APs (of which I've checked - we do have 10K APs so difficult to tell for sure). We're running 8.10.0.7.
As these APs are deployed amongst general residential properties there are a large amount of home broadband SSIDs broadcasting too. Which are being picked up as rogues on Airwave. A lot of which are broadcasting on 2.4GHz channels (not using 1, 6 or 11).
I'm just trying to understand why the AP (1) changed its AAC at the exact time of the DFS log message and why AP (2) reloaded. I can understand that the AP would change channel if needed. But that shouldn't cause the AP to reload or change AAC?
Original Message:
Sent: Jul 31, 2023 02:20 AM
From: Herman Robers
Subject: 5GHZ DFS behaviour on 3xx series APs
Radar events are likely near airports, weather stations, sea/waterways, including military use (which may not always be clear where/when). It may also be some equipment in your or neighboring locations that emit RF signals it shouldn't really.
If you see the events on one location, not on others, it's fair to start with the assumption that the radar detects are actual radar events. If you run early firmware version for your type of AP (unlikely as the AP3xx is around for a while), it may be good to upgrade firmware as radar detection is a software feature that can be improved in case of false-positives (but has to be present in order to be compliant).
If you experience extensive radar events, in many cases that's just on a few channels, or on a few APs (that are positioned sub-optimal versus the source of the radar events), and it makes sense to remove those channels from your ARM/Airmatch planning on all APs or just the APs that show these radar events. The logs should help you to analyze channels & APs to be changed.
------------------------------
Herman Robers
------------------------
If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
Original Message:
Sent: Jul 28, 2023 09:35 AM
From: AdamNewsonCU
Subject: 5GHZ DFS behaviour on 3xx series APs
There appears to be a lot of DFS messages in the debug logs for both APs in this building. Does anyone think this could be caused by a weather/military radar event causing the APs to change channel? They're both 3xx series so follow this rule instead of 5xx which use the zero-wait feature.
"Dynamic Frequency Selection (DFS), a mandate for radio systems operating in the 5 GHz band to identify and avoid interference with Radar systems now supports zero-wait feature. When an 802.11 radio detects radar, it vacates its channel and switches to another channel. This might result in a one minute outage".
What exactly does a 'one minute outage' look like? Does the AP bootstrap or reload at this point?
1. (UWS-MC-A8) *#show ap debug log ap-name 20:4c:03:5a:42:1a
Jul 26 11:31:34 KERNEL(20:4c:03:5a:42:1a@172.30.209.241): [ 236.379982] Enabled radar detection on channel 5280
Standby AAC 131.111.10.88 (last assigned at Wed Jul 26 11:31:34 2023 (2d:0h:57m:30s ago)
-------------------------------------------------------------
2. (UWS-MC-A8) *#show ap debug log ap-name 20:4c:03:5a:3b:d2
Jun 19 08:29:08 KERNEL(20:4c:03:5a:3b:d2@172.30.209.240): [ 301.614358] Enabled radar detection on channel 5580
Up time 39d:5h:26m:53s