单项选择题
When a new trunk link is configured on an IOS based switch, which VLANs are allowed over the link（）。
A.By default, all defined VLANs are allowed on the trunk.
B.Each single VLAN, or VLAN range, must be specified with the switchport mode command.
C.Each single VLAN, or VLAN range, must be specified with the vtp domain command.
D.Each single VLAN, or VLAN range, must be specified with the vlan database command.
单项选择题 What is one benefit of PVST+?（）
单项选择题 When a router is connected to a Frame Relay WAN link using a serial DTE interface, how is the interface clock rate determined（）。
多项选择题 Refer to the diagram. Which three statements describe the router port configuration and the switch port configuration as shown in the topology? （）