Loopback-Detection Action - HP 3100 v2 Series Command Reference Manual

Default level
2: System level
Parameters
external: Enables external loopback testing to test all on-chip functions related to Ethernet
interfaces.
internal: Enables internal loopback testing to test the hardware of Ethernet interfaces.
Description
Use loopback to enable loopback testing on an Ethernet interface.
By default, loopback testing is disabled on Ethernet interfaces.
Enable loopback testing for troubleshooting purposes, such as identifying an Ethernet problem.
During loopback testing, the speed, duplex, mdi, and shutdown commands are not available. In
addition, the port is operating in full duplex mode, regardless of its duplex configuration. After
loopback testing is disabled, the duplex configuration of the port is restored.
Loopback testing is a one-time operation, and is not recorded in the configuration file.
Examples
# Enable internal loopback testing on Ethernet 1/0/1.
<Sysname> system-view
[Sysname] interface ethernet 1/0/1
[Sysname-Ethernet1/0/1] loopback internal
Loop internal succeeded!

loopback-detection action

Syntax
loopback-detection action { no-learning | shutdown }
undo loopback-detection action
View
Ethernet interface view, port group view
Default level
2: System level
Parameters
no-learning: Disables MAC address learning on the interface.
shutdown: Shuts down the Ethernet interface. To bring up the interface again, use the undo
shutdown command.
Description
Use loopback-detection action to configure the action for loop protection on Ethernet interfaces.
Use undo loopback-detection action to restore the default.
By default, a looped interface does not receive or send packets; the system generates traps and log
messages, and deletes all MAC address entries of the looped interface.
When you change the link type of an Ethernet interface by using the port link-type command, the
switch removes the protective action configured on the interface. For more information about the
port link-type command, see "VLAN configuration commands."
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