S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - f e e d b a c k - d o c @ c i s c o . c o m
2-621
Cisco NX-OS System Messages Reference
OL-15994-03
Chapter 2 System Messages and Recovery Procedures
STP Messages
Error Message
STP-2-LOOPGUARD_CONFIG_CHANGE: Loop guard [chars] on port [chars].
Explanation
The spanning tree loopguard configuration for the listed interface has been changed. If
enabled, the interface will be put into blocking state and marked as loopguard inconsistent when the
message age timer expires because no BPDUs were received from the designated bridge. This
feature is mainly used to detect unidirectional links.
Recommended Action
Verify that this is the desired configuration for the listed interface. Correct it
if this is not the desired configuration otherwise no further action is required.
Error Message
STP-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port [chars] on
[chars].
Explanation
The listed interface has received a BPDU and therefore if the inconsistency was due to
an unidirectional link failure, now the problem is not there anymore. The loop guard inconsistency
is cleared for the interface which is taken out of the blocking state if appropriate.
Recommended Action
No user action is required.
Error Message
STP-2-PVSTSIM_FAIL: Blocking [chars] port [chars]: Inconsistent
[chars] PVST BPDU received on VLAN [dec], claiming root [chars]
Explanation
When a MST switch is connected to a PVST+ switch, the CIST (MST00) information
on the port of the MST switch must be consistently better than all the PVST+ messages if the port
is designated or consistently worse than all the PVST+ messages if the port is root. If this constraint
is not respected, the port on the MST switch is blocked in order to prevent a potential bridging loop.
Recommended Action
When STP is converging after a new switch, or switch port is added to the
topology, this condition may happen transiently. The port unblocks automatically in such cases. If
the port remains blocked, identify the root bridge as reported in the message, and configure a worse
or better priority for the VLAN spanning tree consistent with the CIST role on the port of the MST
switch. There could be more inconsistencies than the message indicates, and the port will not
recover until all such inconsistencies are cleared. If you cannot determine which other VLANs have
inconsistencies, disable and reenable the port. This message will appear again and specify another
VLAN with inconsistencies to be fixed. Repeat this process until all inconsistencies on all VLANs
are cleared.
Error Message
STP-2-PVSTSIM_OK: PVST Simulation inconsistency cleared on port
[chars].
Explanation
The listed interface is no longer receiving PVST BPDUs advertising an information
inconsistent with the CIST port information. The PVST Simulation Inconsistency is cleared and the
interface returns to normal operation.
Recommended Action
No user action is required.
