This article provides a step-by-step guide to diagnose and optimize FortiWifi speed.
Scope
FortiAP managed through FortiGate.
Solution
Step 1: Optimal Placement.
Make sure that the AP placement is done as per a per-site survey to identify and address coverage gaps and interference sources.
Place the FortiWiFi device in a central location, elevated and away from obstructions (do not keep the APs on desks).
Physical Barriers: Placing APs near thick walls, metal objects, or large appliances can cause signal reflection and absorption, reducing signal strength and coverage.
Step 2: Optimize Wi-Fi Settings.
Change Wi-Fi Channels:
Interference from other Wi-Fi networks can affect speed. Use a less crowded channel.
Refer to the below KB article to see the nearby interfering sources:
Troubleshooting Tip: Channel utilization is reported high on FortiAP (Managed by FortiGate)
On the FortiAP profile, radio resource provisioning should be enabled on the radios.
Adjust Channel Width:
- For 2.4 GHz, use a 20 MHz channel width to avoid interference.
- For 5 GHz, use 40 MHz or 80 MHz for higher speeds but be cautious of potential interference.
Navigate to the FortiAP profile -> Go to each radio -> Choose the Channel width.
Enable Frequency handoff:
Encourage dual-band devices to use the 5 GHz band for better performance.
The wireless controller monitors the usage of 2.4GHz and 5GHz bands and signals clients to switch to the lesser-used frequency.
Navigate to FortiAP profile > Enable Frequency handoff.
Enable AP handoff:
The wireless controller signals a client to switch to another access point.
Navigate to FortiAP profile > Enable AP handoff.
- High Traffic Areas: Improper placement can result in certain APs overloaded with too many clients, while others are underutilized.
- Bandwidth Bottlenecks: Overloaded APs struggle to provide adequate bandwidth to all connected devices, leading to slow internet speeds.
Set the right Transmit power:
Adjust transmit power to balance coverage and minimize interference. Avoid setting the power to maximum unless necessary.
Set the right Tx power on each radio as recommended in the initial site survey report.
Do not broadcast all APs at 100% power, instead set the Transmit power mode to ‘Auto’ and choose the power range as per the survey report.
FortiGate will auto-adjust the power range on the basis on nearby APs.
Make sure that the test client is near to the FortiAP and the signal strength is good on the FortiGate GUI.
To list the particular station station to the WIFI:
diagnose wireless-controller wlac -d sta | grep -v x.x.x.x
If the issue still exists, capture the below logs and raise a case with the TAC team:
From FAP :
sta fap-get-status cw_diag -c his-chutil cw_diag -c all-chutil cw_diag ksta fap-tech
From FortiGate:
FAP profile configuration screenshot get wireless-controller scan --> List all discovered neighboring APs get wireless-controller rf-analysis --> RF conditions around all APs. get wireless-controller status –-> Show client load over time.