单项选择题 A Cisco Catalyst switch is part of the CIS network. As an experienced network administrator, you are thinking of filtering the traffic within VLANI00 with the use of a VACL named "test" on that switch. Which of the following command will enable that?（）

多项选择题 avoid Layer 2 loops. Which two of the following are most probably the reasons for that preference?（）

单项选择题 As an experienced Network Engineer, you are responsible for network connectivity and system configuration. Which of the following protocols will be supported by Cisco Nonstop Forwarding (NSF)?（）