H3C Technologies H3C WX3000 Series Unified Switches - Manual (Page 125)

15-10
z
To enable loopback detection on a specific port, you must use the loopback-detection enable
command in both system view and the specific port view.
z
After you use the undo loopback-detection enable command in system view, loopback detection
will be disabled on all ports.
z
The commands of loopback detection feature cannot be configured with the commands of port link
aggregation at the same time.
Configuring the Ethernet Port to Run Loopback Test
You can configure the Ethernet port to run loopback test to check if it operates normally. The port
running loopback test cannot forward data packets normally. The loopback test terminates
automatically after a specific period.
Follow these steps to configure an Ethernet port to run loopback test:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet port view interface interface-type interface-number —
Configure the Ethernet port to run loopback
test
loopback { external | internal } Required
z external: Performs external loop test. In the external loop test, self-loop headers (which are made
from four cores of the 8-core cables) must be used on the ports of the device. The external loop test
can locate the hardware failures on the port.
z internal : Performs internal loop test. In the internal loop test, self loop is established in the
switching chip to locate the chip failure which is related to the port.
After you use the shutdown command on a port, the port cannot run loopback test. You cannot use the
speed , duplex, mdi and shutdown commands on the ports running loopback test. Some ports do not
support loopback test, and corresponding prompts will be given when you perform loopback test on
them.
Enabling the System to Test Connected Cable
You can enable the system to test the cable connected to a specific port. The test result will be returned
in five minutes. The system can test these attributes of the cable: Receive and transmit directions (RX
and TX), short circuit/open circuit or not, the length of the faulty cable.
Follow these steps to enable the system to test connected cables: