loopback
Function
The loopback command enables loopback detection on an interface.
The undo loopback command disables loopback detection on an interface.
By default, loopback detection is not configured.
Parameters
Parameter |
Description |
Value |
|---|---|---|
internal |
Configures internal loopback detection on a specified interface. |
- |
Views
Ethernet interface view, GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, port group view
Usage Guidelines
Usage Scenario
When testing some special functions, for example, locating an Ethernet fault, you need to enable loopback detection on Ethernet interfaces to check whether the interfaces are working properly. After loopback detection is enabled on an Ethernet interface, the interface is in Up state if it works properly, and is in Down state if it fails.
Follow-up Procedure
Run the display interface command to check whether the current status of the interface configured with internal loopback is Up. If the current status of the interface is Up, the internal forwarding function works well; otherwise, a fault occurs during internal forwarding.
After loopback detection is enabled on an interface, the Speed field in the display this interface command output indicates the configured interface rate or the rate of the installed optical module, copper module, or network cable, and the Bandwidth field in the display interface ethernet brief command output indicates the actual interface rate.
Precautions
Loopback detection interrupts the operation of Ethernet interfaces and links. After loopback detection is performed, run the undo loopback command to disable loopback detection immediately.
You cannot run the loopback command to perform loopback detection on a fabric port.