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Cisco IE 3000 Switch System Message Guide
OL-13020-01
Chapter 2      Message and Recovery Procedures
SPANTREE Messages
error in the platform-specific code, which causes it to request more or less bits than are possible. 
The first [dec] is the number of bits for the port number, and the second and third [dec] describe the 
valid range.
Recommended Action  Copy the message exactly as it appears on the console or in the system log. 
Research and attempt to resolve the error by using the Output Interpreter. Enter the show version 
user EXEC command to gather data that might help identify the nature of the error. Use the Bug 
Toolkit to look for similar reported problems. If you still require assistance, open a case with the 
TAC, or contact your Cisco technical support representative, and provide the representative with the 
gathered information. For more information about these online tools and about contacting Cisco, see the 
“Error Message Traceback Reports” section on page 1-4.
Error Message  SPANTREE-3-PORT_SELF_LOOPED: [chars] disabled.- received BPDU src mac 
([enet]) same as that of interface. 
Explanation  A BPDU was received on the listed interface with a source MAC address that matches 
the one assigned to the listed interface. This means that a port might be looped back to itself, 
possibly because of an installed diagnostic cable. The interface will be administratively shut down. 
[chars] is the interface that received the BPDU, and [enet] is the source MAC address.
Recommended Action  Check the interface configuration and any cable connected to the interface. 
When the problem is resolved, re-enable the interface by entering the no shutdown interface 
configuration command.
Error Message  SPANTREE-3-PRESTD_NEIGH: pre-standard MST interaction not configured 
([chars]).
Explanation  The message means that the switch has received a prestandard multiple spanning-tree 
(MST) BPDU on an interface that is not configured to send prestandard MST BPDUs. The switch 
automatically adjusts its configuration on the interface and start sending prestandard BPDUs. 
However, the switch does not automatically detect all prestandard neighbors, and we recommend 
that you configure the interface to send prestandard MST BPDUs by using the spanning-tree mst 
pre-standard interface configuration command. This warning message only appears once. [chars] 
is the interface. 
Recommended Action  Use the spanning-tree mst pre-standard interface configuration command on 
all the interfaces to which other switches running Cisco's prestandard MST version are connected. 
We recommend that you migrate all the switches in the network to the IEEE MST standard version.
Error Message  SPANTREE-4-PORT_NOT_FORWARDING: [chars] [chars] [chars] [chars].
Explanation  This message appears when a port-not-forwarding alarm is set or cleared. The first 
[chars] is the mode (for example, assert or clear), and the second [chars] is the severity (for example, 
minor). The third [chars] is the interface name, and the fourth [chars] is the alarm string (for 
example, port not forwarding).
Recommended Action  Copy the message exactly as it appears on the console or in the system log. 
Research and attempt to resolve the error by using the Output Interpreter. Use the Bug Toolkit to 
look for similar reported problems. If you still require assistance, open a case with the TAC, or