TP-Link T3700G-28TQ User Manual page 135

Choose the menu Spanning Tree→STP Security→Port Protect to load the following page.
Configuration Procedure:
Configure the Port Protect features for the selected ports, and click Apply.
Entry Description:
Port Protect

UNIT:
Select:
Port:
Loop Protect:
Figure 8-10 Port Protect
Select the desired unit or LAGs.
Select the desired port for port protect configuration. It is
multi-optional.
Displays the port number of the switch.
Enable or disable the Loop Protect function. It is recommended to
enable this function on root ports and alternate ports.
Loop Protect function is used to prevent loops caused by link
congestions or link failures. With Loop Protect function enabled, the
port will temporarily transit to blocking state when it does not
receive BPDUs. After the link restores to normal, the port will transit
to its normal state, so loops can be prevented.
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