DFS channels not being selected by DCS?

Jamiewyc

Hi,

I've disabled "Avoid 5G DFS channel" but I can't seem to get any of my AP's to pick up anything other than the 36,40,44 and 48 channels using DCS - There's nothing in the logs to indicate why. Am I missing something obvious here?

Zyxel_Judy

Hi @Jamiewyc ,

Here are some troubleshooting steps you can follow:

• 5 GHz channel deployment: Verify that you have selected the 'Manual' option and limited your channel choices to 36, 40, 44, and 48 only
• Blacklist DFS channels in the presence of radar: Verify if this option is enabled and DFS channels were blacklisted when radar was detected.

The configuration should be changed as shown in the screenshot below.

• Interference Check: Use a Wi-Fi analyzer tool to check for neighboring networks that might be using the DFS channels, causing your APs to avoid them.

Generally, the AP will automatically scan the surrounding environment and select the most optimal channel. For further details on DCS, please consult the relevant FAQ: How to solve Co-channel Interference by DCS? — Zyxel Community

Jamiewyc

Hi Judy,

Sorry - why would I set the channels to manual (but your screenshot is highlighting "All channels available")?

Zyxel_Judy

Hi there,

We recommend using this screen above, so that the AP can scan all available channels. If you opt for manual settings, the screen will appear as follows:

Jamiewyc

Hi Judy,

That's completely unrelated and doesn't make any sense….

You stated: "Verify that you have selected the 'Manual' option and limited your channel choices to 36, 40, 44, and 48 only"

Why would I manually set the channels if I want DCS to pickup DFS channels??

Zyxel_Judy

Hi @Jamiewyc ,

Apologies for any confusion. What I meant was that you can check if you've set the option to 'Manual' and selected only channels 36, 40, 44, and 48. Doing so would result in the AP scanning only these four channels currently.

If you've already set the option to 'All Available Channels' and disabled the 'Blacklist DFS Channels in the Presence of Radar,' yet the AP still scans only channels 36, 40, 44, and 48, , please enable Zyxel support by navigating to 'Help' (located at the top right corner) > 'Support Request' > 'Zyxel Support Access', then click 'Enable' and 'Save'.

Additionally, please provide us with the name of your Nebula organization/site here or via the private message by clinking to my account > Message.

Jamiewyc

Hi Judy,

Thanks for that - that's done.

Just to note: We've had really bad performance on both 2.4ghz and 5ghz since installation and have been trying different things to reduce interference (A lot of our AP's will sit at 80%+ on 2.4ghz and we will see spikes over 90% for 5ghz for some APs) hence some of our AP's are not set to use DCS anymore and have been set manually.

Zyxel_Judy

Hi @Jamiewyc ,

The same issue is present across both your Pre School and Senior School sites: some Access Points (APs) are operating in limited power mode, while others are linked at 10/100Mbps speeds. These factors contribute to the low throughput you're experiencing.

To address the issue with APs showing an orange status, please refer to this FAQ: Understanding the Orange Icon Status of Your Nebula AP — Zyxel Community

For optimal performance, it's essential that client devices have a strong signal—ideally at least -70dBm or higher. If you're experiencing low throughput despite a strong signal, consult this FAQ for tips on fine-tuning your wireless environment.: How to resolve the low throughput despite strong signal? — Zyxel Community

Jamiewyc

Hi Judy,

Thank you for this - I'm well aware that some of our AP's are in low power mode/have low link speed but what does this have to do with the DCS issue?

Zyxel_Judy

Hi there,

I understand that my findings may not directly pertain to the DCS issue, but I believe they could shed light on the root cause of the bad performance issues at your site. Addressing these issues should be a priority.

Just to note: We've had really bad performance on both 2.4ghz and 5ghz since installation

As for DCS, it enables the AP to scan the surrounding area for the least congested channel, allowing it to switch channels automatically for optimal performance. Our checks confirm that DCS is active and functioning on your AP.

To further investigate, you can use a Wi-Fi analyzer tool to identify any neighboring networks that might be utilizing DFS channels, which could cause your APs to avoid those channels.

Zyxel_Judy

Hi there,

Thank you for your patience.
Before we conclude this case, we would like to summarize the resolution. Our firmware update/solution for the WAX630A addresses the issue where DFS channels were not being selected by DCS.