Troubleshooting an MSTP configuration

Cause

This section describes the show spanning-tree commands to use to monitor, troubleshoot, and debug the operation of a multiple-instance spanning tree configuration in a network.

The show spanning-tree commands described in this section allow for focusing on increasingly specific levels of operation. For example, you can display debug information for:
  • All MST instances

  • All ports used in one MST instance

  • A specific port or several ports used in one MST instance

Also, you can display the change history for the root (bridge) switch used as the single forwarding path for:
  • All MST regions, STP bridges, and RSTP bridges in an STP network

  • All VLANs on MSTP switches in a region

  • All VLANs on MSTP switches in an mst instance