STP (802.1D)
5.2.4  ports
5.2.3  BridgeID  (5.2.1)
5.2.2  BPDU
5.2.5  Port states
5.2.5.2 BPDU timers
5.3.1 Convergence steps
5.3.5 TCN/TCA
5.4.3 RSTP (802.1W)
5.4.6 RSTP port ststes

root port
designated port (lower interface)
blocking port (higher interface)