Я бы на вашем месте начал с (Cisco Controller) >debug client <MAC addr1>
И повторил эксперимент с band select.
Возможно это поможет понять почему клиенты подключаются на 2,4GHz.
Далее собранные логи можно попробовать распарсить с помощью
https://cway.cisco.com/tools/WirelessDebugAnalyzer/ Band Selection Algorithm
The band selection algorithm affects clients that use 2.4-GHz band. Initially, when a client sends a probe request to the access point, the corresponding client probe’s Active and Count values (as seen from the band select table) become 1. The algorithm functions based on the following scenarios:
Scenario - 1: Client RSSI (as seen from show cont d0/d1 | begin RSSI) is greater than both Mid-RSSI and Acceptable Client RSSI.
Dual band clients—No 2.4-GHz probe responses are seen at any time; 5-GHz probe responses are seen for all 5-GHz probe requests.
Single band (2.4-GHz) clients— 2.4-GHz probe responses are seen only after the probe suppression cycle.
After the client’s probe count reaches the configured probe cycle count, the algorithm waits for the Age Out Suppression time and then marks the client probe’s Active value as 0. Then, the algorithm is restarted.
Scenario - 2: Client RSSI (as seen from show cont d0/d1 | begin RSSI) lies between Mid-RSSI and Acceptable Client RSSI.
All 2.4-GHz and 5-GHz probe requests are responded without any restrictions.
This scenario is similar to the band select disabled.
https://www.cisco.com/c/en/us/td/docs/w ... 11100.htmlВ документе есть Restrictions on Band Selection, возможно в вашем случае вы попадаете на эти ограничения.
