单项选择题
A./38
B./30
C./27
D./23
E./18
F./32
单项选择题 You have a single Class C IP address and a point-to-point serial link that you want to implement VLSM on. Which subnet mask is the most efficient?（）
单项选择题 On the topic of VLSM, which one of the following statements best describes the concept of the route aggregation?（）
单项选择题 Which one of the following varieties of NAT utilizes different ports to map multiple IP addresses to a single globally registered IP address?（）