Loopback-Detection Enable - HP 3600 v2 Series Command Reference Manual

Use undo loopback-detection control enable to restore the default.
By default, loopback detection control is disabled on trunk and hybrid ports.
When a hybrid or trunk port detects a loop condition, it sends traps, whether loopback detection control
is enabled or not. However, only after loopback detection control is enabled will the port perform the
protective action configured with the loopback-detection action command.
This command is not applicable to access ports.
Examples
# Enable loopback detection control on the trunk port Ethernet 1/0/1.
<Sysname> system-view
[Sysname] loopback-detection enable
[Sysname] interface ethernet 1/0/1
[Sysname-Ethernet1/0/1] port link-type trunk
[Sysname-Ethernet1/0/1] loopback-detection enable
[Sysname-Ethernet1/0/1] loopback-detection control enable

loopback-detection enable

Syntax
loopback-detection enable
undo loopback-detection enable
View
System view, Layer 2 Ethernet interface view, port group view
Default level
2: System level
Parameters
None
Description
Use loopback-detection enable to enable loopback detection globally in system view or on interfaces in
Ethernet interface or port group view. To use loopback detection on an Ethernet interface, you must
enable the function both globally and on the port.
Use undo loopback-detection enable to disable loopback detection globally or on Ethernet interfaces.
The undo loopback-detection enable command in system view disables loopback detection on all
interfaces.
By default, loopback detection is disabled on all Ethernet interfaces.
If an interface receives a packet that it sent out, a loop has occurred. Loops may cause broadcast storms,
which degrade network performance. You can enable loopback detection to detect loops on an
interface and, if the interface supports the loopback-detection action command, configure the protective
action (shut down the port, for example) to take on the interface when a loop is detected.
In addition to the configured protective action, the switch also performs other actions to alleviate the
impact of the loop condition. For more information, see Table 1 1.
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