单项选择题
A.When the voice VLAN feature is enabled， all untagged voice and data traffic is sent through the voice VLAN.
B.The voice VLAN feature is enabled by default.
C.The IP phone overrides the priority of all incoming data traffic （tagged and untagged） and sets the CoS value to 0.
D.The default CoS value is 1 for incoming voice and data traffic.
单项选择题 You work as a network engineer for. You study the exhibit carefully. What type of attack would be mitigated by this configuration？（）
多项选择题 You want to enhance the security within the LAN and prevent VLAN hopping. What two steps can be taken to help prevent this？（）
单项选择题 The network administrator has enabled BPDU guard on the LAN. Why is an effective way to prevent an unauthorized rogue switch from altering the spanning-tree topology of this network？ （）