单项选择题
Which Cisco IOS command globally enables port-based authentication on a switch？ （）
A.aaa port-auth enable B.radius port-control enable C.dot1x system-auth-control D.switchport aaa-control enable
单项选择题 Whatdoestheinterfacesubcommandswitchportvoicevlan222indicate？（）
单项选择题 A remote host can be pinged from all switches except one. Which of the following is the most likely reason for this failure？（）
单项选择题 Whatistheresultofenteringthecommandspanning-treeloopguarddefault？（）
