Troubleshooting Tip: DARRP channel assignment on FortiAP WiFi

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Description	This article describes the steps to set DARRP (Distributed Radio Resource Provisioning) channel assignment on FortiAP WiFi.
Scope	FortiAP v7.4.x, FortiGate v7.4.x.
Solution	DARRP feature assigns non-overlapping channels on the FortiAPs managed by FortiGate, and the DARRP is used to address co-channel interference on the Wireless Networks. Ensure FortiAPs are on the latest v7.4.x GA and FortiGate on minimum v7.2.8, v7.4.1, because known DARRP bugs 825182 and 923530 are fixed on FortiOS v7.2.8, v7.4.1, and higher versions: Resolved issues v7.4.1. Remove static override channel settings, if any, from the APs, and enable DARRP (Radio Resource Provisioning) in all radios in the FortiAP profile:   Ensure the FortiGate arrp-default profile has the following configuration in place: config wireless-controller arrp-profile     edit "arrp-default"     weight-weather-channel 0     weight-dfs-channel 0         set include-weather-channel enable         set include-dfs-channel enable end Note: Before v7.0.x, the include-weather-channel and include-dfs-channel will have yes/no options instead of enable/disable. Unset non-default darrp-optimize value, if any, and set it to the default value: config wireless-controller setting     show         unset darrp-optimize end For FortiAP deployments in Europe, ensure the FortiGate firmware is on v7.4.0 and above, because the newer v7.4 and higher versions support additional channels on the 5 GHz band, i.e., UNII-3 channels (149, 153, 157, 161, and 165). Refer to Feature ID 852998: New features or enhancements. In the FortiAP profile, ensure all supported 5 GHz channels are selected on the 5 GHz radio as shown below. This will help DARRP use all the selected channels for DARRP non-overlapping channel assignment on the FortiAPs: During a change window, trigger DARRP channel planning manually using the below command on FortiGate: diagnose wireless-controller wlac -c darrp 1 Note: By default, the DARRP automatically runs every 24 hours (86400 seconds). DARRP schedule can also be defined, refer to: Configuring Distributed Radio Resource Provisioning    9. To view the DARRP channel assignment status on the FortiGate and FortiAP, use the following commands: FortiGate: diagnose wireless-controller wlac -c darrp FortiAP: cw_diag -c darrp Note: If the APs are far from each other (for example, more than 60-80 feet apart or more), then DARRP may not assign a non-overlapping channel because the APs cannot see each other (due to weak neighbor RSSI), and hence, the APs may choose to operate on any channel of their choice, and it should be fine because the chances of co-channel interference are low as the APs are far from each other.  Note: Ensure the 'Dedicated Scan', the DDscan option, is enabled in the FortiAP profile, which puts the 3rd radio on the FortiAP into 'Dedicated Monitor' mode, and this will help in proper DARRP function: Disable dedicated scanning on FortiAP F-Series profiles Note: The new FortiAP v7.4.6 GA, v7.6.2 GA, and above versions fix a known DARRP issue in Radar environments; therefore, before debugging any existing DARRP channel assignment issues, ensure the FortiAP is on v7.6.2 GA or v7.4.6 GA. Related documents: Issue 1140990: DARRP was skipping available DFS channels that initially detected radar signals but t... Resolved issues v7.6.2