Client Behaviour in dual 5/6 GHz environment

[The_Roo]

This post is primarily concerned with Win11 device behaviour under 6E. I'm hoping to hear real-world experience with Meraki 91xx APs, I've read the documentation and I'm still wondering what really happens in real life

If a tri-band-capable client enters a 5GHz-only Wi-Fi domain, it will go through though the usual scanning process to find an SSID with which to associate. It will list available SIDs, the user can select one of the found SSIDs, provide credentials and the client will associate with the 5GHz SSID (AAA permitting) as they are both 5GHz capable. Thats what happens now.

However, assume this same tri-band-capable client moves to a site where there is a 5/6GHz-capable AP broadcasting SSIDs in both 5 and 6 GHz bands with different names (e.g. "5GH" and "6GH"). Within the responses it receives from APs, there will be a Reduced Neighbour Report (RNR) that includes information about all connectivity (including 6GHz) available so it will know there is a 6GHz SSID that it could use to get better performance than staying with the 5GHz SSID.

So here's the question: the client was associated with the 5GHz SSID before, because that was all that was available, and it has the credentials (stored) for the 5GHz SSID, so will it automatically disregard the 6GHz SSID and join the 5GHz SSID, or will it try to join the 6GHz, as the preferred network? If the user didn't select "connect automatically", I assume they could then select the 6GHz manually, provide credentials and the client would join the 6GHz SSID....?

Also, if  the same SSID was broadcast across both the 5GHz and 6GHz bands, will the client behave differently?

[cmr · Accepted solution]

@The_Roo when a client moves from one site to another and loses sight of the connected SSID for a while, it will not treat it like roaming.  There are two distinct configurations here so:

1. different SSIDs - if the client only has credentials for 5GH then it will connect to that, though it may pop up a bubble saying that 6GH is faster.
2. same SSID  - if the signal strength for both 5GHz and 6GHz are similar and the client meets the critera to connect on both bands, then it should prefer the 6Ghz band, but it will be the client's choice.

I just checked my 916x APs and bizarrely every client is connected on the 2.4Ghz band although most SSIDs have 2.4, 5 and 6 all enabled...  Not sure what is going on there!

[GIdenJoe]

Yikes!
I usually try to have the important internal SSID's on the wanted bands only, but in a case where that is not possible this can happen.

[cmr]

It doesn't really matter for me as there isn't another house in WiFi range, so it's only my APs competing for frequencies...

[JustinV]

 If the SSIDs are the same (between 5 & 6 GHz), a client may automatically switch to the 6GHz band if it offers better signal strength/performance. However this is subject to device settings and "nuances".

A device-configured preferred band may commonly take priority, guiding the device to connect to the specified band if it is available and performing well.

Those AP suggestions and band steering messages do influence the device's connection decisions, especially when the device-level preferred band is set to "No Preference" or when the preferred band is not performing optimally.

So...with Windows client settings, don't forget those "Preferred Band" driver settings.