Speed problems with AP6-Pro

I just installed on Sunday. I have 2 X AP6-Pros connected to a Fortinet 124F-POE switch, which is connected via dual 10Gig links to a Fortinet 100F firewall.

Previously I had 2 Fortinet 431F access points which I replaced with the AP6-Pros. The Fortinet APs had no problem pulling between 850mbps to 1gbps fully loaded like the AP6-Pros are now. The AP6-Pros are only pulling around half of that if I am lucky.

Internal speed test (on my network) shows between 550-600 mbps, internet speed test on various sites, speedtest.net, google speedtest, etc. are between 350-550 mbps. The Fortinet APs pulled between 800 mbps to 1 gpbs. on the same internet speed test.

Latency on the Fortinets - <20ms, normally between 11-17ms.
Latency on the AP6-Pros >40ms, low and high I have seen were 108ms was the highest, 30ms lowest.

I have tried several things, as follows:

  1. Disabling as a whole, the DPI. This actually slowed things down by around 100mbps.
  2. Disabling filtering per SSID with a secondary password and “Bypass Filter” turned on. This was even worse, it slowed me down to around 120mbps.
  3. Went through my config on my switches and firewall. Nothing to note there, standard port setup with POE, speed is auto-negotiated to 1gb. I disabled my filtering profiles on both the management network that the AP6-Pros are assigned mgmt IP addresses from, as well as the networks used for wireless access. It had no effect.
  4. Making the network flat. I gave IP addresses to the AP6-Pro on the same subnet that all of my general access clients get DHCP addresses from, no change.
  5. Ran a monitor on the switch ports. One of them was clean, nothing noteworthy, the second one had quite a lot of drops. The switch ports are configured exactly the same. The drops increased when I put the device under heavy load with a speedtest. Same speedtest on the one with nothing noteworthy showed no drops. This one still suffered from the slow network speeds, so I don’t think the drops are very indicative of anything causative.

I am not quite sure what I can do with these from a lower level perspective, if there is a command line interface with more extensive ability to make changes that will have an impact, or give better logging of what is going on, I would like to have access to it. If there is some simple thing I am missing in the cloud manager, I would like to hear about it. I understand that keeping it simple is normally good, but this is so simple, I can’t really troubleshoot anything. If there is documentation on this stuff, please feel free to point it out to me and give me a good old “RTMF!”.


Are the tests apples to apples comparisons? i.e. same channel, same channel width as the previous Fortinet APs? Generally, to get above the ~600mbps mark, you’ll want to be on 160MHz wide channels for 5GHz; you won’t get the speeds you stated on 2.4GHz (again, generally speaking) so I’m going off the assumption that you’re solely referring to 5GHz.

5GHz for sure. 80MHz channel width on both. Generally speaking, I have had poor experience with 160mhz no matter the platform. This was on both the Fortinet and the Alta APs.

4X4 should have a threshold of around 1800 mbps, of course, these only have a gigabit interface, so expectations dampened to match hardware. :slight_smile:

I suspect you’re quoting advertised air speeds which, agree with it or not, is the industry norm. Realistically speaking, you’re going to get roughly 1/3 of the advertised air speed on any platform. Their datasheet states 1147mbps on 2.4GHz and 2402mbps on 5GHz; or 383mbps and 800mbps respectively and that would be on the maximum channel width of course. This explains the 2.5gbps Ethernet port because if you max out both bands, you’re over 1gbps. Ours, for now, is 1gbps because it’s exceedingly rare to hit that cap for any sustained period of time.

At any rate, something isn’t adding up. Their advertised modulation is QAM1024 and we’re doing QAM4096.
They do 4x4 on channel widths up to 80MHz, whereas we’re doing 4x4 up to 160MHz.
So, on paper, we should far exceed their speeds.

And you’re 100% sure you matched up the channels to what the Fortinets were running? Have you run a scan on the Alta APs to ensure those are the best channels to use?

If I may chime in as well… in my testing the Alta AP radios are powerful enough that you will actually get reduced speeds if you blast yourself with the power on high and you are anywhere near the AP… perhaps check your power settings? I know for me I had to turn the 5Ghz power down to 20dBm, and I still have devices with signals in the -40s.

Excellent point @rutman286, another variable to take into consideration!

All of the 5GHz connections are between -41 and -72. I have power set to “auto” because when I tried to manually adjust it, I couldn’t find a sweet spot. Once I set it back to auto, it has worked better, as in, stable signal to pretty much everything that needs it.

Your explanation and quotation of the specs is why I bought the Alta APs. I don’t have any 2.5gbit interfaces, I am not a fan yet…they aren’t really standardized so I am not really interested. I understand why you are asking the questions you are about channels, and width, but all I can do it tell you, yes, I am matching things exactly. The only thing I can think of is that the Fortinet APs are obviously made to work with their other gear, so that may be where the issue is.

If the focus is on my environment and there aren’t any recommendations for anything other than spectrum, I will just keep at it until I either get tired of messing with them or figure out a way to make them work. I do very much appreciate the fact that my Apple TV and HomePods are working as they are supposed to now. It is nice to just turn it on and have it work, not dropping the sound because my HomePods are on a different AP than my Apple TV.

Replying to myself here, sorry if that is bad etiquette. What I was saying above, and not very well, was that I don’t think spectrum is the issue. It feels more like some kind of limitation, perhaps the connection between wireless and physical interfaces, or memory limitations, or perhaps a software issue. Who knows, but it just doesn’t feel like a spectrum issue. Every thing has good coverage without having anything that would be causing reflection issues or co-channel interference.

:laughing: No worries. Would it be possible to get an invite to your site, please? I’ll DM you the email address to invite.

I am seeing some interference on both APs:

I tried to crop as much as I could for your privacy.

The left image shows 3 strong signals on the AP broadcasting on channel 36, so there are 2 hidden SSIDs broadcasting on the same channel. Then you have a mid strength “GetOffMyWiFi” broadcasting on channel 48 but 80MHz wide channel so that interferes with your AP as well

The right image shows a strong hidden network on channel 153 which is the same channel the AP is broadcasting on. Then you have 2 mid/weak on channel 157 but 80MHz wide channels so that will interfere with your AP.

When looking at 5GHz, a 20MHz wide channel affects just that channel. A 40MHz will be that channel + or - 1 channel to the left or right. 80MHz is that channel + or - 2 channels, typically 1 to the left and 1 to the right. 160MHz, you guessed it, that channel + or - 4 channels.

I can adjust based on the scan results, but there will be momentary drops in client connections as it applies the channel change, clients scan, and reconnect.

Thanks for this. Let me try to eliminate a few of those before any changes are made. I think maybe some Apple AirPlay is turned on that shouldn’t be…the “GetOffMyWiFi” SSID is an annoying neighbor who has about 40 Google WiFi Mesh nodes in his house. The Fortinet had WIDS on them and was able to use some ECM to push them away to other channels to clear the air, that may be part of why there is such a big difference as well.

I moved to a couple of DFS channels and things are better, but I am seeing something very odd. I have one of the APs set to use channel 135, but it is actually using channel 120. See screenshots.

Screenshot 2024-01-23 at 15-32-23 TexasHome - Alta
Screenshot 2024-01-23 at 15-32-02 TexasHome - Alta

That’s common within the DFS channels of the spectrum as if there is something transmitting, most devices won’t transmit on that channel, but use a different channel.

What speeds are you getting now?

Latency is much improved, hitting around 12-17ms now. Speeds are running around 650mbps with a marginal signal, haven’t been able to test with a good signal yet because work is getting in my way! :stuck_out_tongue:

I will test in the same place I have been in a bit and update.


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Latency is between 13-23ms. Speeds are between 650-700 mbps, so yes, better. I will keep making tweaks and see if anything makes a difference. I really appreciate you taking the time to look it over and give me some pointers.

Those numbers are really good in my opinion. I wish latency could be that low in my area. Soo many incorrectly set up neighboring APs.

Totally know the pain of all of the consumer grade stuff stomping on the whole neighborhood! They are great from a technology adoption perspective, but tend to eat spectrum like crazy. I was able to reduce a ton of noise that I hadn’t really thought about by turning off Airplay on 3 Roku TVs and turning it off on 3 Apple TV devices. They were polluting the place a lot. I just hadn’t really thought about them because I had turned it off when I set them up…having grandkids and nephews/nieces come over and allowing them unfettered access to remote controls can be a bad thing. :slight_smile:

I have a couple of netAlly AirCheck G3s running so I can capture probably 3 days worth of data and will use that to tweak channels if the data says I need to.

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My pleasure. I’m glad we were able to improve things. 700mbps on 80MHz wide is really good, I echo @rutman286 's sentiments.

I recently discovered that my ISP modem is broadcasting 80MHz in 5GHz and 40MHz in 2.4GHz (which I personally think should be done away with :rofl:). It’s the first ISP modem I’ve had in 10+ years, and I’m rapidly reminded of why I always bought my own. One of them is for their security system (which I don’t have) and the other, get this, is for any other customers of theirs that have the app.

So now the only question is do I build a Faraday cage or just wrap it in tin foil?

I digress, let me know if there’s anything else you run into but it sounds like you’re in solid shape.

HAHAHA! Yeah, my T-Mobile Home Internet in Florida has wireless built into the “gateway”. The service itself isn’t bad at all, but the wireless can’t be shut off, you can only hide the SSID. I am certainly going to be buying my own there.