Which of the following techniques are part of the way to implement STA fast roaming?
After setting up tunnels with the active and standby ACs, the AP sends Echo messages to monitor tunnel status. The Echo messages contain the active/standby status of the tunnels. When the AP detects that the primary tunnel fails, it sends an Echo Request message with the active flag to the standby AC. After receiving the Echo Request message, the standby AC becomes the active AC, and the AP sends STA data to this AC.
When the STA uses the WPA2-802.1x security policy and supports fast roaming, the STA only needs to perform key negotiation, but does not need to pass 802.lx authentication again during roaming.