STP - Per VLAN Spanning Tree plus (PVST+)

Spanning Tree Protocol (STP) ensures a loop free topology at Layer 2. "Classic" STP operates on a switching topology that has a single VLAN.

Per VLAN spanning tree plus (PVST+) is a version of STP that is able to calculate a spanning tree topology for each VLAN. It takes into account the logical VLAN topology of a set of switches to create loop free Layer 2 switching topologies.

PVST+ is the default version of STP on all modern Cisco switches, and it is compatible with MST.