多项选择题
A.BDPUs will be sent out every two seconds
B.The time spent in the listening state will be 30 seconds
C.The time spent in the learning state will be 15 seconds
D.The maximum length of time that the BPDU information will be saved is 30 seconds
E.This switch is the root bridge for VLAN 200
F.BPDUs will be sent out every 10 seconds
单项选择题 Iftherootbridgefails，configurationBPDUswillnolongerbesent.WhichSTPtimerwillhavetoexpirebeforetheotherswitchescanactivelyrestoreconnectivitywithtopologychangeprocedureofSTP？（）
多项选择题 Given the above diagram and assuming that STP is enabled on all switch devices， which twostatements are true？（）
问答题 Refer to the output shown on switch SW1 below： Warning： Spantree port fast start should only be enabled on ports connected to a single host.Connecting hubs， concentrators， switches， bridges， etc. to a fast start port can cause temporaryspanning tree loops. Use with caution. Spantree ports 4/1-24 fast start enabled. What command could you enter to reproduce this output？