While reviewing an existing network design, you are discussing the characteristics of different STP versions. Which protocol minimizes unicast flooding during a Topology Change Notification in a…

Rapid PVST+ implements the IEEE 802.1w rapid reconfiguration mechanism on a per-VLAN basis, restricting MAC address flushing only to the port receiving the topology change notification rather than invalidating all learned addresses, which significantly reduces the duration and scope of unknown unicast flooding in networks with many VLANs.

MST maps multiple VLANs to fewer spanning tree instances, so a topology change in one instance flushes MAC addresses for all VLANs sharing that instance simultaneously, causing broader unicast flooding across many VLANs than a per-VLAN rapid protocol.

Classic STP (IEEE 802.1D) flushes the entire MAC address table across all bridge ports upon receiving a Topology Change Notification, producing maximum unicast flooding until entries are relearned through normal traffic.

PVSTP+ is based on classic STP convergence behavior and flushes all MAC address entries for the affected VLAN when a TCN is processed, resulting in more extensive unicast flooding compared to the selective flushing used by Rapid PVST+.