Enabling Loopback Test - 3Com 4500 PWR 26-Port Configuration Manual

Operation
Enable loopback port
control on the trunk or
hybrid port
Enable the loopback port
auto-shutdown function
Configure the system to
run loopback detection
on all VLANs of the
current trunk or hybrid
port
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.
After you use the undo loopback-detection enable command in system view, loopback detection
will be disabled on all ports.
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...
Enter system view
Enter Ethernet port view
Enable loopback test
Command
loopback-detection control
enable
loopback-detection
shutdown enable
loopback-detection
per-vlan enable
Use the command...
system-view
interface interface-type interface-number
loopback { external | internal }
12-7
Remarks
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.
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.
Optional
By default, the system runs loopback
detection only on the default VLAN of
the current trunk or hybrid port.
—
—
Required
Remarks