Technical information

AX Series L2 Loop Detection Configuration Guide (Edition 2)

(1) Detection of the L2 loop status via message logs, show logging, and SNMP traps

When an L2 loop is detected and the port is blocked due to this loop, message logs are displayed as shown below.

These logs can be viewed also in the log message history shown by the show logging command.

Display example

For details about log messages, see the manual Software Manual Message Log Reference.

If SNMP traps are enabled, trap notification to the SNMP manager is also available. Details of SNMP traps

supported by the L2 loop detection functionality are as follows.

Table 2.4-1 SNMP traps supported by the L2 loop detection functionality

Type Meaning Issued when

axsL2ldLinkDown Transition of a line to the

communication disabled

state via L2 loop detection

This trap is issued when the operating state of an

interface is changed from ACTIVE (communication

enabled) to DISABLE (communication disabled) by L2

loop detection.

axsL2ldLinkUp Transition of a line to the

communication enabled

state via the

automatic-restoration

functionality of L2 loop

detection

This trap is issued when the operating state of an

interface is changed from DISABLE (communication

disabled) to ACTIVE (communication enabled) by the

automatic-restoration functionality of L2 loop

detection.

axsL2ldLoopDetection L2 loop detection This trap is issued when an L2 loop is detected.

This trap is issued every 60 seconds while the L2 loop

still exists.

For more details about MIB information, see the manual Software Manual MIB Reference for each device.

E1>sh logging

...

EVT 06/26 17:19:57 E4 VLAN 20800001 0700:000000000000 L2LD : Port(0/24): inactivated because of

loop detection from port(0/24).

EVT 06/26 17:19:57 E4 VLAN 20800005 0700:000000000000 L2LD : Port(0/1): loop detection from

port(0/24).

...

--- Port 0/24 is deactivated due to L2 loop detection sent from port 0/24.

--- L2 loop with source port 0/24 is detected at port 0/1.