FortiAP 231F Slow Wi-Fi Speeds

[sagvan]

Hello, everyone

We have already experienced slow Wi-Fi speeds on our campus. We have installed one Fortigate 100F  firewall (version: 6.4.6) and multiple FortiAP 231F access points (version: 7.0).

We have tested the cables and quite various scenarios, but we feel like the devices need to be upgraded.

I just noticed that, as shown in the screenshot, one AP's channel utilization is 77% when there is no single user connected to it. Would an upgrade fix this? What does this even mean? Is it really this problem that is causing slow Wi-Fi speeds? What's the solution?

Thank you all in advance!

[Jakob-AHHG]

Any reason that FG is not on 7.2.7 and then your AP's on 7.4.2?

Do you know if your client connect to 2.4 og 5 GHz radio?
Is your SSID Tunnel or Bridge?

Maybe make an SSID you only have on 5GHz and test that?

I have just installed 231F here and have about 600Mbit on the 5G radio.

[sagvan]

Thank you for the reply, @Jakob-AHHG 

We are planning on upgrading the firmware versions.
There is no reason other than that I already recommended it and my superior asked me to ignore it.

Now, since we have this problem, I got permission for the upgrade.

The problem with only 5GH radio frequency is some devices' don't support it, so we need 2.4 GH as well.

What do you think? Is this due to the outdated firmware or anything you can think of?

[Jakob-AHHG]

Hmm..
How is your Radios configured in the Operation Profile?

Do you have AP enabled on Radio 1 & 2 and Monitor Only on Radio 3?

Or is it because it's using Radio 2 as monitor when idle?

5GHz: I'm not saying you should make an SSID with 5-only for production, but make one for test. ;) 

[sagvan]

We have not changed the channels. We worked on the default settings.

Here are a few screenshots you may understand:

[sagvan]

I forgot to answer your question.
The SSIDs run on Tunnel mode 

[sagvan]

This is the FortiAP Profile:

[Jakob-AHHG]

Can't remember if FortiAP/WLC is auto-assigning a channel, if you have none selected in the profile?
On never FortiOS versions, you select them like this:

I would select, at least, all UNI1+2+2E and UNI-3. 140-144 is not enabled here in Denmark.
Also, I would recommend a visualizer tool, that you can also make surveys with. We use NetSpot (Win & Mac): netspotapp[dot]com.
NetSpot has build-in iPerf3 testing, and your FortiGate has iPerf3 server build-in (at least from 7.0), so you can test the raw speed of your infrastructure.
The KB on the subject, state it's for testing in-between-fortigates, but you can use it to test local links as well. :) 
The steps is:
1: Enable the system-levet iperf server on the FG:

# config system global
set speedtest-server enable
end

 2: Enable 'Speed Test' on the Interface/VLAN you like to test against.

Administrative Access: [x] Speed Test

3: Use an iPerf3 client (like NetSpot), here is the needed settings in NetSpot:

NetSpot 3 iPerf client settings

So do some real-life tests, see what you actually get.

[sagvan]

Do I need this complex method when I can test the raw speed by connecting to the firewall through LAN, which I have already used to test the speed?

[Jakob-AHHG]

If you have other means of testing the speed over your wifi, that's fine - it was just an option (and it's not really that complex).