To do…
Use the command…
Remarks
or port group
view
Enter port
group view
port-group manual
port-group-name
To configure loopback detection
on one interface, enter Ethernet
interface view.
To configure loopback detection
on a group of Ethernet interfaces,
enter port group view.
Enable loopback detection on the
interfaces
loopback-detection enable
Required
Disabled by default.
Enable loopback detection control
loopback-detection control enable
Optional
Disabled by default.
IMPORTANT:
This command is available only on
hybrid and trunk interfaces.
Enable loopback detection in all
VLANs on the trunk or hybrid
interface
loopback-detection per-vlan
enable
Optional
By default, a trunk or hybrid
interface performs loopback
detection only in its port VLAN
(PVID).
Set the protective action to take on
the interface when a loop is
detected
loopback-detection action
{
no-learning
|
shutdown
}
Optional
By default, a looped interface does
not receive or send packets.
With the
shutdown
keyword
specified, the looped port will be
automatically shut down and its
physical state changes to Loop
down. After the loop is removed,
use the
undo shutdown
command
on the port to recover its
forwarding capability.
NOTE:
•
To use single-port loopback detection on an Ethernet interface, enable the function both globally and on
the interface.
•
To disable loopback detection on all interfaces, run the
undo loopback-detection enable
command in
system view.
•
To enable a hybrid or trunk interface to take the administratively specified protective action, you must use
the
loopback-detection control enable
command on the interface.
Setting the MDI mode of an Ethernet interface
NOTE:
Fiber interfaces do not support the MDI mode setting.
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