单项选择题 Which of the following is the purpose of QoS?（）

单项选择题 A network administrator needs to add an additional connection to a room. The administrator adds a new Ethernet switch and must connect it to an existing switch. Which cable type should be used to connect the two switches?（）

单项选择题 A user connecting a laptop to a wall jack is prompted for user credentials before being grantedaccess to the network. Which of the following is MOST likely implemented on the switch?（）