H3C Technologies H3C S3100 Series Switches - Manual (Page 147)

1-6
Operation Command Remarks
Enable loopback detection
on a specified port
loopback-detection enable
Optional
By default, the loopback detection function
is enabled on ports if the device boots with
the default configuration file (config.def); if
the device boots with null configuration, this
function is disabled.
Enable loopback port
control on the trunk or
hybrid port
loopback-detection control
enable
Optional
By default, the loopback port control
function is enabled on ports if the device
boots with the default configuration file
(config.def); if the device boots with null
configuration, this function is disabled.
Enable the loopback port
auto-shutdown function loopback-detection shutdown
enable
Optional
By default, the loopback port
auto-shutdown function is enabled on ports
if the device boots with the default
configuration file (config.def); if the device
boots with null configuration, this function is
disabled.
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.
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.
Table 1-6 Enable loopback test
Operation Command Remarks
Enter system view system-view —
Enter Ethernet port view interface interface-type interface-number —
Enable loopback test loopback { external | internal } Optional