A.RSTP significantly reduces topology reconverging time after a link failure.
B.RSTP expends the STP port roles by adding the alternate and backup roles.
C.RSTP port atates are blocking，discarding，learing，orforwarding.
D.RSTP also uses the STP proprsal-agreement sequence.
E.RSTP use the same timer-baseed processas STP on point-to-pointlinks.
F.RSTP provides a faster transition to the forwarding state on point-to-point links than STP does.