单项选择题
A.transport type all
B.transport output all
C.transport preferred all
D.transport input all
多项选择题 As a frame leaves a Layer 3 device, the Layer 2 encapsulation information is changed from what it was when it entered the devicE.For what two reasons can this happen? （）
单项选择题 Which additional configuration step is necessary in order to connect to an access point that has SSID broadcasting disabled（）。
多项选择题 At which layers of the OSI model do WANs operate (Choose two.)（）。