The loopback command enables the Ethernet interface to perform internal or external loopback.
The undo loopback command disables the loopback.
By default, loopback is disabled on Ethernet interface.
loopback
undo loopback
None
Ethernet interface view, Layer-2 Ethernet interface view
2: Configuration level
When some special function tests are carried out, the interface is set to perform loopback only.
# Enable the interface GigabitEthernet 0/0/1 to perform loopback.
<sysname> system-view [sysname] interface GigabitEthernet 0/0/1 [sysname-GigabitEthernet 0/0/1] loopback