+If link monitoring is enabled with the ``-m`` command line flag, one
+additional pthread is launched which will check the link status of each
+physical NIC port and will update the carrier status of the corresponding
+KNI interface(s) to match the physical NIC port's state. This means that
+the KNI interface(s) will be disabled automatically when the Ethernet link
+goes down and enabled when the Ethernet link goes up.
+
+If link monitoring is enabled, the ``rte_kni`` kernel module should be loaded
+such that the :ref:`default carrier state <kni_default_carrier_state>` is
+set to *off*. This ensures that the KNI interface is only enabled *after*
+the Ethernet link of the corresponding NIC port has reached the linkup state.
+
+If link monitoring is not enabled, the ``rte_kni`` kernel module should be
+loaded with the :ref:`default carrier state <kni_default_carrier_state>`
+set to *on*. This sets the carrier state of the KNI interfaces to *on*
+when the KNI interfaces are enabled without regard to the actual link state
+of the corresponding NIC port. This is useful for testing in loopback
+mode where the NIC port may not be physically connected to anything.
+