Description
This article describes how to prevent neighbourly FortiAPs from choosing the same channel after DARRP calculation.
Scope
FortiGate v7.0 and up, FortiAP.
Solution
Sometimes after a DARRP calculation, neighbourly FortiAP may end up transmitting on the same channel after a DARRP calculation due lack of configuration, insufficient RF environment information, and sometimes due to challenging RF environment conditions.
To ensure DARRP can operate as expected, follow the KB articles below to enable DARRP correctly:
Troubleshooting Tip: DARRP channel assignment on FortiAP WiFi
Troubleshooting Tip: How to verify the DARRP status and trigger the DARRP process manually
If neighbourly FortiAPs are using the same channel still can be observed, make sure if devices are collecting RF environmental data on all WI-FI Bands using the following commands on FortiAP CLI:
LAB-UF# apscan
fmvap bssid freq BW rssi cap live age darrp chan age bsscolor ssid
No X4:01:68:a7:7d:b8 36 80 -60 1111 641180 18 -1 -1 35 _Bad_Neigborgh
...sumarized output...
Total 94 APs found on Radio 0
fmvap bssid freq BW rssi cap live age darrp chan age bsscolor ssid
No 66:db:f7:c2:6c:69 11 20 -75 1c11 95121 296 -1 -1 0
...sumarized output...
Total 108 APs found on Radio 1
fmvap bssid freq BW rssi cap live age darrp chan age bsscolor suppressed ssid
No X4:01:68:a7:7d:b8 36 80 -60 1111 641180 18 -1 -1 35 0_Bad_Neigborgh
...sumarized output...
Total 205 APs found on Radio 2
LAB-UF# stascan
sta mac bssid chan live age suppressed
9a:e8:70:04:59:70 f4:fb:b8:92:75:ff 11 133235 125207 0
...sumarized output...
Total 585 STAs
Outputs may be different depending on which FortiAP is used. If no data is displayed after input commands above, ensure ddscan or at least channel monitoring is enabled on the FortiAP profile as directed in earlier articles.
On FortiGate CLI, use the following command to check if the wireless controller is receiving FortiAP data to use it on DARRP calculations:
Fortigate# diagnose wireless-controller wlac -c ap-rogue
... sumarized output...
...warning, this comand may display a lot of data...
C - Configured (G:accept, B:rogue, S:suppress, U:unconfigured)
M - AC managed (V:vdom, C:AC, N:unmanaged)
W - On wire (Y:yes, N:no)
P - Phishing (F:fake, O:offending, N:no)
Total Rogue-AP:640 Rogue-AP-WTP(displayed):1215 Rogue-AP-WTP(total):1215
Total Entries: 652
After DARRP calculation, the possibility of observing FortiAP using the same channel in the same area should be a lot less.
Using the same channel in some areas may be the best Channel choice and should not be an issue if Channel utilisation is not more than 70% sustained for a long time. This scenario is not uncommon on dense FortiAP deployments or dense WIFI utilisation areas. This channel choice should be temporary in most cases.
If the DARRP calculation is still not satisfying requirements, it can be customised by setting more weight for managed FortiAPs on the ARRP profile:
weight-managed-ap Weight in DARRP channel score calculation for managed APs (0 - 2000, default = 50).
Start using a value of 100 or 150 and observe the DARRP calculation. To know more details about DARRP calculations, consult
Following document: Understanding DARRP
