Enabling loopback test – H3C Technologies H3C S3600 Series Switches User Manual
Page 167
1-7
Operation
Command
Remarks
Configure the system to
run loopback detection
on all VLANs of the
current trunk or hybrid
port
loopback-detection
per-vlan enable
Optional
By default, the system runs loopback
detection only on the default VLAN of
the current trunk or hybrid port.
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 loopback-detection control enable command and the loopback-detection per-vlan
enable command are not applicable to access ports. When the link type of a non-access port
changes to access, the two commands already configured on the port become invalid
automatically.
Enabling 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 enable loopback test:
To do...
Use the command...
Remarks
Enter system view
system-view
—
Enter Ethernet port view
interface interface-type interface-number
—
Enable loopback test
loopback { external | internal }
Required
z
external: Performs external loop test. In the external loop test, self-loop headers must be used on
the port of the switch ( for 100M port, the self-loop headers are made from four cores of the 8-core
cables, for 1000M port, the self-loop header are made from eight cores of the 8-core cables, then
the packets forwarded by the port will be received by itself.). 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.
Note that:
z
After you use the shutdown command on a port, the port cannot run loopback test.