单项选择题
A. A command that can be entered in any configuration mode.
B. A command that supports all protocols.
C. A command that is implemented in all IOS versions.
D. A command that is set once and affects the entire router.
E. A command that is available in every release of IOS.
单项选择题 After logging into a router, you type in "enable" and then enter the correct password when prompted. What is the current router prompt symbol at this point?（）
多项选择题 Which three of the following basic network services are provided by the Cisco IOS?（）
单项选择题 Which of the commands below would you enter if you wanted to see the configuration register of your router?（）