802.1D STP Legacy Spanning Tree
802.1W RSTP fast spanning tree, high convergence efficiency
802.1S MSTP multi-instance spanning tree, now used more, CCNP content
PVST Cisco proprietary, not compatible with other spanning trees
PVST+ later has this product compatible with other manufacturers
fast pvst +
Election of spanning tree, the smaller the root bridge is, the higher the priority
bridge id = priority + MAC address
Extended bridge id = priority + VLAN id + MAC address
Election on a non-root bridge interface
