A.Router A is the master virtual router， and Router B is the backup virtual router. When Router A fails， Router B will become the master virtual router. When Router A recovers， Router B will maintain the role of master virtual router.
B.Router A is the master virtual router， and Router B is the backup virtual router. When Router A fails， Router B will become the master virtual router. When Router A recovers， it will regain the master virtual router role.
C.Router B is the master virtual router， and Router A is the backup virtual router. When Router B fails， Router A will become the master virtual router. When Router B recovers， Router A will maintain the role of master virtual router.
D.Router B is the master virtual router， and Router A is the backup virtual router. When Router B fails， Router A will become the master virtual router. When Router B recovers， it will regain the master virtual router role.

A.Switches S1 and S3 will be able to exchange traffic but neither will be able to exchange traffic with Switch S2
B.Switches S1， S2， and S3 will be able to pass traffic between themselves. However， if there is a topology change， Switch S2 will not receive notification of the change.
C.Switches S1， S2， and S3 will be able to pass traffic between themselves.
D.IEEE 802.1D and IEEE 802.1w are incompatible. All three switches must use the same standard or no traffic will pass between any of the switches.

A.The designated port is the switch port on every nonroot bridge that is the chosen path to theroot bridge. There can be only one designated port on every switch. The designated portassumes the forwarding state in a stable active topology. All switches connected to a given segment listen to all BPDUs and determine the switch that will be the root switch for a particular segment.
B.The disabled port is an additional switch port on the designated switch with a redundant link to the segment for which the switch is designated. A disabled port has a higher port ID than the disabled port on the designated switch. The disabled port assumes the discarding state in astable active topology.
C.The backup port is a switch port that offers an alternate path toward the root bridge. The backup port assumes a discarding state in a stable， active topology. The backup port will be present on nondesignated switches and will make a transition to a designated port if the current designated path fails.
D.The root port is the switch port on every nonroot bridge that is the chosen path to the root bridge. There can be only one root port on every switch. The root port assumes the forwarding state in a stable active topology.

A.Switch SW1 has been configured with the spanning-tree vlan 1 root primary global configuration command.
B.Switch SW1 has been configured with the spanning-tree vlan 1 root secondary global configuration command.
C.Switch SW1 has been configured with the spanning-tree vlan 1 priority 24577 global configuration command.
D.Switch SW1 has been configured with the spanning-tree vlan 1 hello-time 2 global configuration command.
E.The root bridge has been configured with the spanning-tree vlan 1 root secondary global configuration command.

A.They have been configured with the spanning-tree bpdufilter disable command.
B.They have been configured with the spanning-tree bpdufilter enable command.
C.They have been configured with the spanning-tree bpduguard disable command.
D.They have been configured with the spanning-tree bpduguard enable command.
E.They have been configured with the spanning-tree guard loop command.
F.They have been configured with the spanning-tree guard root command.

A.All ports of the root switch SW_A will remain in forwarding mode throughout the reconvergence of the spanning tree domain.
B.Switch SW_A will change its spanning tree priority to become root for VLAN 2 only.
C.Switch SW_A will remain root for the default VLAN and will become root for VLAN 2.
D.No other switch in the network will be able to become root as long as switch SW_A is up and running.

A.The command will be rejected by the switch.
B.Interfaces FastEthernet0/13 and FastEthernet0/14 will no longer be bundled.
C.Dynamic Trunking Protocol will be turned off on interfaces FastEthernet0/13 and FastEthernet0/14.
D.Interfaces FastEthernet0/13 and FastEthernet0/14 will only allow traffic from the native VLAN.
E.Interfaces FastEthernet0/13 and FastEthernet0/14 will continue to pass traffic for VLANs 88，100，360.

A.All secure addresses will age out and be removed from the secure address list. This will cause the security violation counter to increment.
B.The first address learned on the port will be removed from the secure address list and be replaced with the new address.
C.The interface will be placed into the error-disabled state immediately， and an SNMP trap notification will be sent.
D.The packets with the new source addresses will be dropped until a sufficient number of secure MAC addresses are removed from the secure address list.

A.Switch2# configure terminal Switch2（config）# interface range gigabitethernet3/1 -2 Switch2（config-if）# channel-group 5 mode auto
B.Switch2# configure terminal Switch2（config）# interface range gigabitethernet3/1 -2 Switch2（config-if）# channel-group 5 mode passive
C.Switch2# configure terminal Switch2（config）# interface range gigabitethernet3/1 -2 Switch2（config-if）# channel-group 5 mode desirable
D.Switch2# configure terminal Switch2（config）# interface range gigabitethernet3/1 -2 Switch2（config-if）# channel-group 5 mode on

A.ip routing
B.no ip routing
C.router eigrp 1
D.no router eigrp 1
E.mls qos
F.no mls qos