The network diagram is as follows:
The ACs work in HSB mode. After a revertive switchover, new STAs cannot go online and all APs get offline.
Remove and insert the cable connecting the active AC to the switch. After the active AC gets online and detects the standby AC, a revertive switchover is triggered immediately. The VRRP state of the active AC is BACKUP for a flash of time. Four or more than four packets are lost during the revertive switchover.
STP is enabled on the switch port connected to the AC.
Disable STP on the switch (Huawei S5710) connected to the AC.
Analyze logs to check whether the VRRP revertive switchover time is the same as that configured on the active AC.
Check the devices that the VRRP packets pass through to locate which device discards the packets.