单项选择题
A. Check the physical cable.
B. Issue the command activate interfaces fe-0/0/1.5 .
C. Issue the command delete interfaces fe-0/0/1.5 disable.
D. Reconfigure the IP address.
单项选择题 You have been asked to use a 23-bit network mask to segment the network block 209.18.12.0.How many usable host addresses will there be per subnet?（）
单项选择题 You have been allocated a /22 network.How many usable hosts are available?（）
单项选择题 What are the usable hosts on the .128.0/19 network?（）
