Port Management
Loopback Detection Settings
166
Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
10
-
UDLD
—Select to enable automatic error recovery mechanism for the UDLD
shutdown state.
-
Loopback Detection
—Select to enable error recovery mechanism for ports shut
down by loopback detection.
-
Storm Control
—Select to enable error recovery mechanism for ports shut down by
storm control.
-
Link Flap Prevention
—Select to minimize the disruption to your network.
Enabled, this command automatically disables ports that experience link-flap
events.
STEP 3
Click
Apply
to update the global setting.
To manually reactivate a port:
STEP 1
Click
Port Management
>
Error Recovery Settings
.
The list of inactivated interfaces along with their
Suspension Reason
is displayed.
STEP 2
Select the interface to be reactivated.
STEP 3
Click
Reactivate
.
Loopback Detection Settings
Loopback Detection (LBD) provides protection against loops by transmitting loop protocol
packets out of ports on which loop protection has been enabled. When the switch sends out a
loop protocol packet, and then receives the same packet, it shuts down the port that received
the packet.
Loopback Detection operates independently of STP. After a loop is discovered, the port that
received the loops is placed in the Shut Down state. A trap is sent and the event is logged.
Network managers can define a Detection Interval that sets the time interval between LBD
packets.
The following loop cases can be detected by the Loopback Detection protocol:
•
Shorted wire
—Port that loop backs all receiving traffic.
