MST Configuration and VLAN Specific STP Overrides

When configuring MST (Multiple Spanning Tree), the no spanning-tree vlan X command takes precedence over MST instance configurations that include that VLAN. This command essentially disables all types of STP on that VLAN. If you disable spanning tree for a specific VLAN using this command, that VLAN will:

  1. Not participate in any MST instance, even if explicitly mapped
  2. Not generate or process any BPDUs
  3. Have spanning tree completely disabled

This behavior means the VLAN will operate in a pure bridging mode without any loop prevention mechanisms. While this interaction between commands is technically possible, it's recommended to avoid such configurations in production networks to maintain clear and predictable network behavior.

https://networklessons.com/spanning-tree/multiple-spanning-tree-mst