多项选择题
A.A CSU/DSU terminates a digital local loop
B.A modem terminates a digital local loop
C.A CSU/DSU terminates an analog local loop
D.A modem terminates an analog local loop
E.A router is commonly considered a DTE device
F.A router is commonly considered a DCE device
多项选择题 At which layers of the OSI model do WANs operate?（）
单项选择题 A new subnet with 12 hosts has been added to the network. Which subnet address should this network use to provide enough useable addresses while wasting the fewest addresses（）。
多项选择题 A network administrator wants to ensure that only the server can connect to port Fa0/1 on a Catalyst switch. The server is plugged into the switch Fa0/1 port and the network administrator is about to bring the server onlinE.What can the administrator do to ensure that only the MAC address of the server is allowed by switch port Fa0/1? （）