A.show spantree backbonefastB.show spantree statisticsC……

单项选择题The network is displayed in the diagram below： You use the following information for switch SWA：  Port Mode Encapsulation Status Native VLAN fa0 1 desirable n-802.1q trunking 5 Port VLANs is allowed on trunk fa0  1 1-100， 102-1005  Port VLANs is owned and active in management domain fa0 1 1-6. 8-100， 102-115， 197-999， 1002-1005  Port VLANs in spanning tree forwarding state and not pruned fa0 1 1-6， 8-100， 102-105， 108-999， 1002-1005  SW users in VLAN 107 complain that they are unable to gain access to the resources through theSW1 router.  What is the cause of this problem？（）

A.VLAN 107 is not configured on the trunk
B.VLAN 107 does not exist on switch SWA
C.VTP is pruning VLAN 107
D.Spanning tree is not enabled on VLAN 107
E.None of the other alternatives apply

单项选择题Whatshouldyoudotoreducespanning-treeprotocolBPDUtrafficduringextendedperiodsofinstabilityinyourVLANs？（）

A.Combine all the VLAN spanning trees into a single spanning tree
B.Set forward delay and max-age timers to the maximum possible values
C.None of the choices
D.Change the router VTP server mode
E.Disable the root bridge

多项选择题Exhibit SW1#show spanning-tree vlan 200 VLAN200 Spanning tree enabled protocol iee eRoot ID Priority 32968 Address 000c.ce29.ef00 Cost 19 Port 2 （FastEthernet0 2） Hello time 10 Sec Max Age 20 sec Forward Delay 30 sec  Bridge ID Priority 32968 （priority 32768 sys-id-ext 200） Address 000c.ce2a.4180 Hello Time 2 sec Max Age 20 Sec Forward Delay 15 sec  Interface Role Sts Cost PrioNbr Type Fa0 2 Root FWD 19 128.2 P2p Fa0 3 Altn BLK 19 128.3 P2p   Based on the show spanning-tree vlan 200 output shown in the exhibit， which two statementsabout the STP process for VLAN 200 are true？（）

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？（）

A.hello timer
B.BPDU timer
C.Forward_delay timer
D.Max_age timer
E.Dead timer
F.Wait timer

多项选择题Given the above diagram and assuming that STP is enabled on all switch devices， which twostatements are true？（）

A.DSW11willbe elected the root bridge
B.DSW12 will be elected the root bridge
C.ASW13 will be elected the root bridge
D.P3/1 will be elected the nondesignated port
E.P2/2 will be elected the nondesignated port
F.P3/2 will be elected the nondesignated port