Hi,
fact 1: my WLAN AP provides a dual band WLAN (2.4GHz and 5 GHz) with same network name. The client can decide which band he wants to use.
fact 2: my HA is running on a PI 4B
Is there a way to force one of the bands in HA? 2.4GHz performance is bad because of many other 2.4 networks in my house…
Br, Michael
It’s probably not what you want to hear but it will be much more stable connection to HA if you use an ethernet cable. 5Ghz has a more limited range compared to 2.4Ghz
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No. Router side it may be possible
Why? A few nearby networks won’t necessarily interfere with each other. Have you tried other channels.
Ethernet is best. Server on wifi is bad idea.
Fact 3: Connect your server(s) via ethernet.
Fact 4: Profit
Sharing the made / model of the WLAN AP may assist with better answers.
A single SSID on dual band radios, you have very little ability to dictate from a client which band would be used.
Splitting the WLAN bands to separate SSID’s solves the problem easily, enabling connecting to a dedicated 5Ghz only Wi-Fi network.
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Hi,
thx for your feedbacks. Yes, it´s a single SSID for both bands. Splitting would be theoretically possible, but I would have to reconfigure all connected devices (because of the new SSID). The alternativ is to install a network cable. I hoped that I can prevent both, but it seems I have no luck…
Br, Michael
It’s not an alternative but realy the go-to solution for servers. 
Band steering would in come handy here - but again, not for servers (you want maximum uptime → ethernet!) but for your client devices 
If this were mine…
-
ethernet - don’t use wifi for servers. Many reasons mostly stability.
-
plan to split the wifi bands. IoT devices generally use the cheapest wifi chips and many can’t understand 5ghz… and when faced with two APs on the same ssid with different bands - get confused and can’t connect (I’ve had very poor experience with band steering in general) this will cause you issues later. And then you’ll end up splitting the band to solve it… Might as well do it now. (I make my IoT wireless as plain and vanilla as possible no steering no shaping no funky bandwidth adjustments)
Sorry to correct you on this matter but this false statements come up a lot and other users then sadly copy this… 
Obviously to safe bucks many MCU’s (like $2 ESPs) don’t include both wifi bands because of costs. What this means if it is a “legacy” device only supporting 2.4GHz it simply can’t see anything(
) happening on the 5GHz band - it can’t even (try) to connect to a 5GHz SSID (like you describe). 
Band steering can only work if a client supports both, 2.4+5GHz. It actually doesn’t even need to be supported by the client as the AP can just respond on 5GHz only when a connection attempt is made: 
Band steering works by responding only to 5 GHz association requests and not the 2.4 GHz requests from dual-band clients
IEEE 802.11n-2009 - Wikipedia
I think many from this weird (and often simply false) explantions come from onbarding processes like, for example “smart config” (not so smart!). 
Your smartphone is connecting to your 5Ghz WiFi and therefore keep broadcasting SSID and password in this radio band. While your smart home device still waits in 2.4Ghz radio band for the required SSID and password to complete pairing.
Pairing failed? Read this before you try again (help.ewelink.cc)
In a nut 
shell: Due to the fact that they are sending and receiving information in two different bands, they won’t talk to each other and the pairing will fail. 
In a nutshell: No wifi “legacy” (only 2.4GHz) should have any problems connecting to a SSID that also broadcasts in 5GHz because it simply can’t see (or connnect) to it 
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I understand what your saying O. And practice says otherwise…
Basically. Tell this to my friends washing machine and about 20 esp32 devices sitting in a drawer that Absolutely REFUSE to connect on mixed ssids. Nest Protects also hate them.It took two days of my life trying to unscrew why it SHOULD WORK (Because exactly what you said) and it doesn’t. It’s most likely due to minor implementation differences between vendors. I bought a bunch to try… They’re still in the drawer.
Therefore I stand on why I said what I said. The tech details may be slightly off but the net net is the exact same no connect on mixed networks and they amazingly start connecting when you split them. So I get what you’re saying and I don’t setup mixed networks on purpose because it simply doesn’t work well with cheap esp32s and im not interested in trying to figure out why when splitting the network is a perfectly acceptable answer.
“Beware of false knowledge; it is more dangerous than ignorance.” - George Bernard Shaw.
I know you like to dig into these things.
I have a scenario where there is verification that the issue exists. How about trying to figure why and get a solution instead of saying hey your (absolutely verified probable problem with empirical evidence) can’t possibly be a problem.
The workaround (and yes it’s a work around) is split network ssids. Because yeah it SHOULD work. But I hate to break it to you and everyone who makes these things it doesn’t work very well. And practical applications state it doesn’t.
So you can espouse on about false data and whatever. Op doesn’t have to split network. I honestly do not care.
But I’ve setup literally hundreds of wireless networks and a good portion(well over 1/4) of those who chose combined ssids have issues with IoT and a fair amount of hose we ended up splitting later. The ones with isolated 2ghz run almost flawlessly. (except roborock that’s another animal) When researching it came down to combined ssids being the delta. Books v practical applications.
Thus, the recommendation. Do with it as you please. And I’d love to learn why but again I have other things to work on. There is no harm in splitting it and it solves tons of problems.
It’s funny and a bit like groundhog 
day - happens like every year 2025, 2024, 2023…
Well, that’s weird, I deploy literally only cheap esp’s (or esp based devices) since around 7 years without any hiccups 
In the end Brandolini’s laws applies and I call it a day 
I don’t have split bands and I have everything that only supports 2.4GHz working well with dual-band, but I have had instances where a crappy 2.4 device would not connect until I disabled the 5GHz band. Once connected I re-enabled the 5GHz and it continued to work.
So I agree, there are some flakey 2.4GHz devices that just don’t play well with dual-band networks!
That very much sounds like you couldn’t pair a device from manufactures like adax, mill heaters, sonoff and probably many hundreds (or even thousands?) more that use techniques like “smart config” which requires your phone/tablet or whatever device used to deploy wifi credentials to be on the same (2.4GHz) band as the device you want to deploy.
The SmartConfig
is a provisioning technology developed by TI to connect a new Wi-Fi device to a Wi-Fi network. It uses a mobile application to broadcast the network credentials from a smartphone, or a tablet, to an un-provisioned Wi-Fi device.
The advantage of this technology is that the device does not need to directly know SSID or password of an Access Point (AP). This information is provided using the smartphone. This is particularly important to headless device and systems, due to their lack of a user interface.
SmartConfig - ESP32 - — ESP-IDF Programming Guide latest documentation
You probably can expect that many modern routers and access points to have band steering on by default. This most likely will result in 5GHz connection for most or all of your dual band devices like phones and tablets. 
Very, very much sounds like 
Pairing failed? Read this before you try again
Good to know. Thanks!
Finally I decided to install a LAN cable. Thx to all!
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