Cisco Catalyst 4500 Series Message Manual page 112

SPANTREE Messages
Error Message SPANTREE-2-LOOPGUARD_UNBLOCK: Loop guard unblocking port [char] on
[char].
Explanation
unidirectional link failure, the problem does not exist anymore. The loop guard inconsistency is
cleared for the interface, which is taken out of the blocking state.
Recommended Action
Error Message SPANTREE-2-PVSTSIM_FAIL: Blocking [char] port [char]: Inconsitent
[char] PVST BPDU received on VLAN [dec]
Explanation
the root for all PVST+ spanning trees. Looping occurs if any PVST+ spanning tree has a root with
a better preference than IST. To prevent looping, the port, which is on the MST switch that receives
the superior message from the PVST+ side, is blocked by root guard.
When STP is converging after a new switch or a switch port is added to the topology, this condition
occurs transiently. The port unblocks automatically in such cases.
Recommended Action
and configure a worse priority for the VLAN spanning tree. There could be better PVST roots than
the message indicates, and the port will not recover until all such roots are cleared. If you are unsure
whether the roots are cleared, disable and enable the port again.
Error Message SPANTREE-2-RECV_1Q_NON_1QTRUNK: Received 802.1Q BPDU on non 802.1Q
trunk [char] [char].
Explanation
received on the listed interface. The interface was in trunk mode but was not using 802.1Q
encapsulation. The interface ID is [char].
Recommended Action
interface to which it is connected are in the same mode (access or trunk). If the mode is trunk, verify
that both interfaces have the same encapsulation (ISL or 802.1Q). Once these parameters are
consistent, spanning tree automatically unblocks the interface.
Error Message SPANTREE-2-RECV_BAD_TLV:Received SSTP BPDU with bad TLV on
[char][char].
Explanation
BPDU is discarded. [char] is the interface ID.
Recommended Action
console or in the system log, contact your technical support representative, and provide the
representative with the gathered information.
Catalyst 4500 Series Switch Cisco IOS System Message Guide Release 12.2(31)SGA
2-92
The listed interface received a BPDU, and if the inconsistency was due to an
This is an informational message only. No action is required.
When a PVST+ switch is connected to an MST switch, the CIST (MSTOO) becomes
If the port remains blocked, identify the root bridge as reported in the message,
A Shared Spanning Tree Protocol (SSTP) bridge protocol data unit (BPDU) was
Verify that the configuration and operational state of the listed interface and the
The listed interface received an SSTP BPDU that was missing the VLAN ID tag. The
If the error message reappears, copy the message exactly as it appears on the
Chapter 2 Messages and Recovery Procedures
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