Loopback-Detection Enable - 3Com H3C S3100 16C SI Manual

H3C Loopback Detection Feature Manual
Release 2107
After the loop is removed, the port will automatically resume the normal forwarding
state.
With the function disabled on the trunk or hybrid port, the system will only send log
messages to the terminal, and the port is still in the normal forwarding state.
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.
Note that this command is invalid for an access port.
Related command: loopback-detection enable.
Example
# Enable the loopback port control function on Ethernet 1/0/1.
<H3C> system-view
System View: return to User View with Ctrl+Z.
[H3C] interface ethernet 1/0/1
[H3C-Ethernet1/0/1] port link-type trunk
[H3C-Ethernet1/0/1] loopback-detection control enable

2.1.2 loopback-detection enable

Syntax
loopback-detection enable
undo loopback-detection enable
View
System view or Ethernet port view
Parameter
None
Description
Use the loopback-detection enable command to enable the loopback detection
function on the current port to detect whether an external loopback occurs on the port.
Use the undo loopback-detection enable command to disable the loopback
detection function on the port.
1) If a loop is found on an access port, the system will set the port to the block state
(ports in this state cannot forward data packets), send log messages to the
terminal, and remove the corresponding MAC forwarding entry.
If you have enabled the loopback port auto-shutdown function (with the
loopback-detection shutdown enable command) on the access port, the system
Chapter 2 Loopback Detection Configuration
2-2
Commands