Technical information

AX Series L2 Loop Detection Configuration Guide (Edition 2)

2.4 Troubleshooting with operation commands

This section describes the basic operations of the L2 loop detection functionality in the configuration example.

When the L2 loop detection functionality detects an L2 loop, the detection of a loop is output in the message log

of the device and a log entry is recorded. It is also possible to issue an SNMP trap.

When an L2 loop is detected in a device, the loop status and other information can be viewed for each device

using the operation commands related to the L2 loop detection functionality as shown below.

After that, investigate the location of the loop by referring to this information as well as the network

configuration diagram and the actual wiring status.

#1: When the port is set to be blocked at the detection of an L2 loop (send-inact-port)

and has no link destination after the loop status is removed

Figure 2.4-1 Operation (troubleshooting) procedure related to the L2 loop detection

functionality

L2 loop occurs! (0H(1) Detecting the L2 loop status)

- Message log

- SNMP trap

1H(2) Identifying the loop location

- show logging (Shows the log message)

- show loop-detection (Shows the loop status)

Determining the cause of the loop (incorrect connection or incorrect setting)

If the cause is an incorrect setting

Check the configuration and layout.

Correct the configuration,

etc.

If the cause is an incorrect

connection

Disconnect the cable.

2H(3) Restoring blocked ports and removing the loop status

display

- show port (Shows the port status)

activate (Releases the blocked port)

- show loop-detection (Shows the loop status)

show loop

detection

Clears the

Down(loop)

status