多项选择题 After replacing the NIC card of a PC on the LAN, your Cisco switch shows a new MAC address is attached to that port. Which of the following answer choices below correctly describe a MAC address?（）

多项选择题 Which of the following correctly describe the various functions and virtues of a router?（）

多项选择题 When comparing and contrasting the similarities and differences between bridges and switches, which of the following are valid statements?（）