H3C Technologies H3C S12500 Series Switches - Manual (Page 19)

11
Configuring loopback testing on an Ethernet interface
If an Ethernet interface does not operate correctly, you can enable loopback testing on it to identify the
problem.
If an Ethernet interface is in a loopback test, it does not forward data traffic.
Configuration restrictions and guidelines
• The loopback external configuration command is available only on the Ethernet interface that
supports 10-G XFP transceiver modules.
• Internal loopback testing can be enabled on interfaces in DOWN state, but not on those
administratively shut down.
• The speed, duplex, port-mode, mdi, combo enable, and shutdown commands are not available
during a loopback testing.
• During loopback testing, an Ethernet interface operates at its highest speed in full duplex mode.
When you disable loopback testing, the rate and duplex mode of the interface restore.
Configuration procedure
To enable loopback testing on an Ethernet interface:
Step Command Remarks
40. Enter system view. system-view N/A
41. Enter Ethernet interface view. interface interface-type
interface-number
N/A
42. Bring up the interface. undo shutdown N/A
43. Enable loopback testing. loopback { external | internal }
Optional.
By default, loopback testing is
disabled.
Configuring Layer 2 Ethernet interfaces
Layer 2 Ethernet interface configuration task list
Task Remarks
Configuring a manual port group
Optional
Applicable to Layer 2 Ethernet interfaces
Setting speed options for auto negotiation on an
Ethernet interface
Optional
Applicable to 100-Mbps or 1000-Mbps Layer 2
Ethernet interfaces
Configuring storm suppression for an Ethernet
interface Optional
Applicable to Layer 2 Ethernet interfaces
Configuring jumbo frame support
Optional
Applicable to Layer 2 Ethernet interfaces