Banning 2.4GHz clients from 5GHz wireless

Hello,

My is configured with two radios: one for 2.4 Ghz and another for 5Ghz. However, some 2.4 Ghz clients connect to the 5Ghz radio, which could downgrade quality of transmissions of 5Ghz. How to force connection on 5Ghz client on 5Ghz server (or ban 2.4 Ghz clients from a 5Ghz radio)? The best would be that a 5Ghz AP does not appear in a scan from a 2.4 Ghz client.

Kind regards,
furies

Clients try to pick the strongest/best AP when connecting.

If you have different SSIDs for 2.4 and 5 GHz networks, and give the device only the passphrase for the 5 GHz network, it can't connect to the 2.4 GHz network. And vice versa.

But that will decrease fault tolerance in case one of the radios is down.

Anoter solution: MAC filtering on 5GHz - deny all exept allowed client's MACs. IMHO it's more flexible as You can always allow/deny clients on-the-fly.

how does a 2.4G client connect to a 5G radio? they would need to have both a
2.4G and 5G radio in the client.

How does a client that has both bads degrade communications quality on 5G? they
would be like any other 5G-only client once they are connected.

now, if you have both bands bridged in a single network, broadcases span both
and you have other issues, but just because someone is able to talk on 2.4G as
well as 5G, that doesn't mean that they will slow down the 5G network.

David Lang

1 Like

This feature is called "Band Steering". I think it's implemented by having APs stop responding to clients on 2,4 GHz for a period of time after they saw them on 5 GHz.

I would like to avoid 5ghz clients downgrade speed to 2,4Ghz on the same AP and prevent the AP from turning into a 2.4 Ghz AP. Is there a way for an AP to advertise supported speed and force 5Ghz without banning the AP?

I would like to avoid 5ghz clients downgrade speed to 2,4Ghz on the same AP
and prevent the AP from turning into a 2.4 Ghz AP. Is there a way for an AP to
advertise supported speed and force 5Ghz without banning the AP?

you don't understand how wifi works, 2.4G clients connecting don't slow down 5G
clients (unless you are doing broadcasts that span both bands, and you just put
them on two different SSIDs and networks to prevent that)

This won't prevent 'slow' 5GHz clients from connecting and slowing down 5GHz
communications, see the make-wifi-fast work on airtime fairness for the best way
to prevent slow clients from having drastic effects on faster clients.

Some chipsets let you specify what speeds they will accpet, and let you disable
some of the lower speeds (unfortunantly, the specs say that some housekeeping
traffic like SSID broadcasts is done at the lowest possible speeds)

David Lang

I've used that approach for some time - but I wouldn't recommend it. While it basically worked, it caused my clients to require longer times connecting (since they first tried to connect to the band which they were blacklisted on) and sometimes longer interruptions after changing the room, etc.

I ended up setting two different names for the 2.4Ghz and 5Ghz bands. If I want clients to be able to use both bands, I would configure both networks on the client, and if I want to have a client only use one band, I would only give it the credentials for that band.

This is not real "band-steering", but it works rather well and solved one issue for me where one client device which is 5G capable would cause the 5G radio firmware to crash when it's connected.

Maybe it's Your hardware problem as firmware has tendency to crash and was not stable (I guess only). I've never seen connection lags even on old TP-Link WDR3600. On that ancient router connection time was ca. 2-3sec and it was client devices' connected: Android longer, Windows shorter (my guests' iOS even longer). Moreover, clients prefered 2.4 network as its signal was stronger.
But as I wrote, that's only my observations...