Which two table types are CEF components？（）

单项选择题WhichprocessplaysamajorroleinthecreationoftheCEFadjacencytable？（）

A.Address Resolution Protocol （ARP）
B.PDU header rewrite
C.NetFlow switching
D.hello packet exchange

单项选择题Whichofthefollowingcommandscanbeissuedwithoutinterferingwiththeoperationofloopguard？（）

A.Switch（config-if）#spanning-tree guard root
B.Switch（config-if）#spanning-tree portfast
C.Switch（config-if）#switchport mode trunk
D.Switch（config-if）#switchport mode access

单项选择题A port in a redundant topology is currently in the blocking state and is not receiving BPDUs. To ensure that this port does not erroneously transition to the forwarding state，  which command should be configured to satisfy the requirement？（）

A.Switch（config）#spanning-tree loopguard default
B.Switch（config-if）#spanning-tree bdpufilter
C.Switch（config）#udld aggressive
D.Switch（config-if）#spanning-tree bpduguard

单项选择题Whichspanning-treecommandwouldcauseaPortFast-enabledinterfacetoloseitsPortFast-operationalstatusanddisableBPDUfilteringifitreceivesBPDUs？（）

A.spanning-tree guard root
B.spanning-tree portfast bpduguard default
C.spanning-tree bpduguard enable
D.spanning-tree bpdufilter enable
E.spanning-tree portfast bpdufilter default

单项选择题Whichofthefollowingconditionsguaranteesthatabroadcaststormcannotoccur？（）

A.a native VLAN mismatch on either side of an 802.1Q link
B.BPDU filter configured on a link to another switch
C.Spanning Tree Protocol enabled on both Layer 2 and multilayer switches
D.PortFast enabled on all access and trunk ports