单项选择题
A.transport type all
B.transport output all
C.transport preferred all
D.transport input all
单项选择题 On the network 131.1.123.0/27, what is the last IP address that can be assigned to a host?（）
单项选择题 What will an Ethernet switch do if it receives a unicast frame with a destination MAC that is listed in the switch table（）。
多项选择题 Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network? （）