wpa_supplicant seems to prefer 2.4GHz over 5GHz

Jouni Malinen j at w1.fi
Wed Feb 15 03:04:19 PST 2017

On Wed, Feb 15, 2017 at 08:37:57AM +0000, John Frankish wrote:
> Ref: https://bugzilla.kernel.org/show_bug.cgi?id=175401

That does not include wpa_supplicant debug log showing the BSS selection
step. You would need to run wpa_supplicant without the -B command line
argument to allow the log to continue through the connection.

> Does anybody know why wpa_supplicant seems to prefer 2.4GHz to 5GHz?

It should not; quite the opposite.. 5 GHz is preferred for the
connection. That said, it looks like you are using an older version of
wpa_supplicant. I would recommend re-running this with the current
hostap.git snapshot or at least the last released version and providing
the debug log from wpa_supplicant if you are still seeing the 2.4 GHz
BSS being preferred.

> What does wpa_supplicant use to decide which frequency to connect to?

If you have BSSs from the same ESS (i.e., APs with same SSID) on
multiple channels, wpa_supplicant tries to estimate the expected
reliability and throughput of the connection through each available BSS
and select the one that is likely to result in best connection. This
determination is also taking into account the likelihood of less
interference on the 5 GHz band and giving higher priority to it.

Jouni Malinen                                            PGP id EFC895FA

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