Loopback-Detection Control Enable - 3Com 5500-EI PWR Reference Manual

<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] interface ethernet 1/0/1
[Sysname-Ethernet1/0/1] loopback internal
Loopback internal succeeded.

loopback-detection control enable

Syntax
loopback-detection control enable
undo loopback-detection control enable
View
Ethernet port view
Parameters
None
Description
Use the loopback-detection control enable command to enable the loopback detection control
feature on the current trunk or hybrid port.
Use the undo loopback-detection control enable command to disable the loopback detection control
feature on the trunk or hybrid port.
This function needs to be used in conjunction with the loopback detection function. For details, refer to
the loopback-detection enable command. When a loopback is detected in a VLAN on a trunk or
hybrid port, you can use this function to control the working status of the port.
If this feature is enabled on the trunk or hybrid port, when loopback is found on the port, the system
sets the port to the block state (where the port cannot forward data packets), sends log messages
to the terminal, and removes the corresponding MAC forwarding entry. After the loop is removed,
the port automatically resumes the normal forwarding state.
If this feature is disabled on the trunk or hybrid port, when loopback is found on the port, the system
merely reports a Trap message, and the port still works normally.
By default, the loopback detection control feature is disabled on the trunk or hybrid port.
Note that, this command is not applicable to access ports. When the link type of a non-access port
changes to access, the loopback-detection control enable command already configured on the port
becomes invalid automatically.
Related commands: loopback-detection enable.
Examples
# Enable the loopback detection control feature on Ethernet 1/0/1.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] interface ethernet 1/0/1
[Sysname-Ethernet1/0/1] port link-type trunk
[Sysname-Ethernet1/0/1] loopback-detection control enable
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