Force MAC OSX users to use 5Ghz

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Hi - we have a common SSID "Wifi Secure" for both 2.4 and 5Ghz bands.  We have an issue where MAC OSX devices  always seem to connect on 2.4 GHz, and there is no way of disabling 2.4 as an option (unlike on most PCs).  Is there any solution to help MAC devices prioritize 5 Ghz?
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David Kinnaird

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Posted 5 months ago

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Igor Tunakin

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Hi,
I know two ways, how it coul be done:

1. You can implement a Band Balancing  feature to load balance the client between the 2,4 and 5 GHz. All dual-band client radios transmit probe requests on both the 2.4 and 5 GHz bands looking for an AP. The AP can see, that client has a dual-band radio. AP will then respond to the client using only 5 GHz. 
This feature is  set to 25/75  by default. It means, that 25% of clients connecting to the 2,4 GHz Band.  You can change this ratio from the CLI:
ruckus(config)# band-balancing
ruckus(config-band-balancing)# percent-2.4G 25
Of course you can not be sure that your particularly MAC device will  connect to 2,4 GHz.

2. The second way is: using much more Tx Power of the 5 GHz radio (5 dB compared to 2.4 GHz is a  good choice). Then the client radio will identify the 5 GHz radio as having a stronger signal and connect to it.
(Edited)
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Jakob Peterhänsel

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Well, it's the devices responsibility to connect to the radio it thinks are the best.
As mentioned by Igor above, you can do some tricks, but why do you think the devices select 2.4GHz and not 5?
Just looked at one of our ZD's, and there 4/7 Mac OS devices connect to 5GHz radios.iOS ration is 12/51..
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David Kinnaird

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Thanks both for comments.  Not sure why the OSX client is choosing 2.4.  Its often a remote AP, rather than the closest.  So combination of Band and AP selection.  We have increased BSS Minrate to 12Mbps, but this has not fixed issue. 
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izagatsky

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As far as I know, Mac OS is supposed to always prefer 5 GHz over 2.4. But in practice, it seems to also like to re-connect to the last AP,  instead of the strongest signal, which then may connect using 2.4GHz.
Perhaps reducing channelization or power levels may help. 

This year I just turned off 2.4 GHz completely on our main SSID, and that simplified things. I've left it on the guest network, on the off chance that some device doesn't support 5 Ghz, and needs 2.4 GHz, but those devices are rather rare these days.


See:  https://support.apple.com/en-us/HT206207

Selection criteria for band, network, and roam candidates

macOS always defaults to the 5 GHz band over the 2.4 GHz band. This happens as long as the RSSI for a 5 GHz network is -68 dBm or better.

If multiple 5 GHz SSIDs meet this level, macOS chooses a network based on these criteria:

  • 802.11ac is preferred over 802.11n or 802.11a.
  • 802.11n is preferred over 802.11a.
  • 80 MHz channel width is preferred over 40 MHz or 20 MHz.
  • 40 MHz channel width is preferred over 20 MHz.