Configuration restrictions and guidelines
On an interface that is physically down, you can only perform internal loopback testing. On an
•
interface administratively shut down, you cannot perform internal or external loopback testing.
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The speed, duplex, mdi, and shutdown commands are not available during loopback testing.
During loopback testing, the Ethernet interface operates in full duplex mode. When you disable
•
loopback testing, the port returns to its duplex setting.
Configuration procedure
To enable loopback testing on an Ethernet interface:
Step
1.
Enter system view.
2.
Enter Ethernet interface view.
3.
Enable loopback testing.
Configuring the link mode of an Ethernet interface
This feature is supported on only routers configured with SAP modules.
Depending on the hardware structure of interface cards, for a device, some interfaces can operate only
as Layer 2 Ethernet interfaces (in bridge mode), some can operate only as Layer 3 Ethernet interfaces (in
route mode), but others can operate either as Layer 2 or Layer 3 Ethernet interfaces (you can set the link
mode to bridge or route).
You can configure the link mode in system view or in Ethernet interface view, which produces the same
result. The link mode configuration in system view applies to multiple interfaces, and the link mode
configuration in interface view applies only to the current interface.
Configuration restrictions and guidelines
Before you change the link mode of an Ethernet interface, make sure the other commands have
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been successfully configured. When the link mode of an Ethernet interface is being changed, you
cannot perform any other configuration.
After you change the link mode of an Ethernet interface, all settings of the Ethernet interface are
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restored to their defaults under the new link mode.
The link mode configuration for an Ethernet interface in system view and in interface view
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supersedes each other.
You can change the link mode of only the active port of a combo interface. To activate the other port,
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make sure the active port operates in bridge mode and activate the other port with the undo
shutdown command.
Configuration procedure
To change the link mode of the specified Ethernet interfaces in system view:
Step
1.
Enter system view.
Command
system-view
interface interface-type
interface-number
loopback { external | internal }
Command
system-view
6
Remarks
N/A
N/A
By default, loopback testing is
disabled.