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Catalyst 3750, 3560, 3550, 2975, 2970, and 2960 Switch System Message Guide
OL-8551-04
Chapter 3 Message and Recovery Proced ures
SPANTREE Messages
Error Message SPANTREE-2-BLOCK_PVID_PEER: Blocking [chars] on [chars]. Inconsistent
peer vlan.
Explanation The spanning-tree port associated with the listed spanning-tree instance and interface
will be held in the spanning-tree blocking state until the port VLAN ID (PVID) inconsistency is
resolved. The listed spanning-tree instance is that of the native VLAN ID of the interface on the peer
switch to which the listed interface is connected. The first [chars] is the interface, and the second
[chars] is the spanning-tree instance.
Recommended Action Verify that the configuration of the native VLAN ID is consistent on the
interfaces on each end of the IEEE 802.1Q trunk connection. When interface inconsistenci es are
corrected, spanning tree automatically unblocks the interfaces.
Error Message SPANTREE-2-CHNL_MISCFG: Detected loop due to etherchannel
misconfiguration of [chars] [chars].
Note This message applies to Catalyst 3750, 3560, 2975, 2970, and 2960 sw itches.
Explanation A misconfiguration of a channel group has been detected. For example, the ports on one
side of the EtherChannel either are not configured to b e in the channel or failed to bundle into the
channel, and the other side has successfully bundled the ports into the EtherChannel. The first
[chars] is the port, and the second [chars] is the VLAN.
Recommended Action Identify the local ports by using the show interfaces status err-disabled
privileged EXEC command, and then check the EtherChannel configuration on the remote device
by using the show etherchannel summary privileged EXEC command on the remote device. After
the configuration is correct, enter the shutdown and then no shutdown interface configuration
commands on the associated port-channel interfaces.
Error Message SPANTREE-2-LOOPGUARD_BLOCK: Loop guard blocking port [chars] on
[chars].
Explanation The spanning-tree message age timer has expired becaus e no BPDUs were received
from the designated bridge. Because this condition could be caused by a unidirectional-link fail ure,
the interface is put into the blocking state and marked as loopguard-inconsistent to prevent possible
loops from being created. The first [chars] is the port name, and the second [chars] is the
spanning-tree mode displayed in the show spanning-tree privileged EXEC command.
Recommended Action Enter the show spanning-tree inconsistentports privileged EXEC command
to review the list of interfaces with loopguard inconsistencies. Find out why devices connected to
the listed ports are not sending BPDUs. One reason might be that they are not running the STP. If
so, you should disable loop guard on the inconsistent interfaces by using the spanning-tree guard
none interface configuration command or by starting the STP on the remote side of the links.