1-19DescriptionUse the loopback command to perform a loopback test on the current Ethernet port to check whetherthe Ethernet port works normally. The loopback test terminates automatically after running for a specificperiod.By default, no loopback test is performed on the Ethernet port.Examples# Perform an internal loop test on Ethernet 1/0/1. system-viewSystem View: return to User View with Ctrl+Z.[Sysname] interface ethernet 1/0/1[Sysname-Ethernet1/0/1] loopback internalLoopback internal succeeded.loopback-detection control enableSyntaxloopback-detection control enableundo loopback-detection control enableViewEthernet port viewParametersNoneDescriptionUse the loopback-detection control enable command to enable the loopback detection controlfeature on the current trunk or hybrid port.Use the undo loopback-detection control enable command to disable the loopback detection controlfeature on the trunk or hybrid port.This function needs to be used in conjunction with the loopback detection function. For details, refer tothe loopback-detection enable command. When a loopback is detected in a VLAN on a trunk or hybridport, you can use this function to control the working status of the port.z If this feature is enabled on a trunk or hybrid port, when loopback is found on the port, the systemputs the port into the controlled working status and removes the MAC address entriescorresponding to the port.z If this feature is disabled on a trunk or hybrid port, when loopback is found on the port, the systemjust reports a Trap message, and the port still works normally.By default, the loopback detection control feature is disabled on the trunk or hybrid port.Note that this command is invalid for an access port.Related commands: loopback-detection enable.Examples# Enable the loopback detection control feature on Ethernet 1/0/1.
