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Configuring Loopback Detection
Configuring Loopback Detection
Context
After loopback detection is enabled on an interface using the loopback command, the Ethernet interface or link on the interface cannot function properly. When the loopback detection test is complete, run the undo loopback command to disable it immediately.
Loopback detection needs to be enabled for special function testing, for example, Ethernet interface diagnosis. When loopback detection is enabled on an Ethernet interface, the interface works in full-duplex mode. When loopback detection is disabled, the interface restores to the default configuration.
Connect the transmit and receive ends with a cable to form a loop so that the device receives the signals sent by itself.
Software loopback
Remote loopback (external loopback)
The local interface does not forward packets received from the remote interface based on their destination addresses. Instead, it sends the packets back to the remote interface.
Local loopback (internal loopback)
Packets sent from an interface are sent back to the local device.
An Ethernet interface does not support remote loopback.
Procedure
Run system-view
The system view is displayed.
Run interfaceinterface-typeinterface-number
The interface view is displayed.
Run loopbackinternal
Internal loopback detection is configured on the Ethernet interface.
By default, loopback detection is disabled on an Ethernet interface.
