Spanning Tree Versions

MSTP and RSTP automatically detect the version of Spanning Tree being used on a LAN. RSTP bridges receiving MSTP BPDUs interpret them as RSTP BPDUs. MSTP and RSTP bridges receiving STP BPDUs will switch to use STP BPDUs when sending on the port connected to the STP bridge. MSTP incorporates a force version feature that allows you to administratively force MSTP to behave as STP or RSTP. This will cause all ports of the bridge to transmit STP or RSTP BPDUs. Use the force version feature when the MSTP bridge is attached to a device that cannot properly handle a non-STP BPDU.

Note

Forcing a bridge to STP will prevent it from joining a region and will disable rapid reconfiguration.