(Step 2)interface 1/0/31no shutdownspanning-tree port mode enableswitchport protected 0exitinterface 1/0/32no shutdownspanning-tree port mode enableswitchport protected 0exit(Step 3)interface vlan 100tagged 1/0/31tagged 1/0/32exitinterface vlan 200tagged 1/0/31tagged 1/0/32exitinterface vlan 300tagged 1/0/31tagged 1/0/32exitDebugging and Verifying MSTP ConfigurationsTo debut and verify MSTP configuration, use the following commands.• Display BPDUs.EXEC Privilege modedebug spanning-tree mstp bpdu• Display MSTP-triggered topology change messages.debug spanning-tree mstp eventsExamples of Viewing MSTP ConfigurationsTo ensure all the necessary parameters match (region name, region version, and VLAN to instance mapping), examine your individualrouters.To show various portions of the MSTP configuration, use the show spanning-tree mst commands.To view the overall MSTP configuration on the router, use the show running-configuration spanning-tree mstp in EXECPrivilege mode.To monitor and verify that the MSTP configuration is connected and communicating as desired, use the debug spanning-tree mstpbpdu command.Key items to look for in the debug report include:• MSTP flags indicate communication received from the same region.• As shown in the following, the MSTP routers are located in the same region.• Does the debug log indicate that packets are coming from a “Different Region”? If so, one of the key parameters is not matching.• MSTP Region Name and Revision.• The configured name and revisions must be identical among all the routers.Multiple Spanning Tree Protocol (MSTP) 549
