单项选择题
A switch is configured as a vtp sever with a domain name of CCNA.Which cisco ios privileged mode command,followed by are load of the swith,will reset the VTP management domain name of the switch to a NULL value?（）
A.#vtp domain unset B.#delete vlan.dat C.#novtp domain D.#vtp domain null
单项选择题 哪个路由协议默认用带宽和延迟作为metrics值？（）
多项选择题 Which can be done to secure the virtual terminal interfaces on a router？（）
多项选择题 At which layers of the OSI model do WANs operate (Choose two.)（）。
