200-301 Question 270
Single answerA network administrator is tasked with summarizing the following IPv4 subnets into a single prefix for efficient routing: 192.168.16.0/24, 192.168.17.0/24, 192.168.18.0/24, and 192.168.19.0/24. Which summarized prefix should be used?
- A
192.168.16.0/22
- B
192.168.16.0/23
- C
192.168.0.0/20
- D
192.168.16.0/21
Show answer and explanation
Correct answer: A
Explanation
The summarized prefix must cover all the given subnets without including unnecessary addresses. The range 192.168.16.0 - 192.168.19.255 can be represented by the prefix 192.168.16.0/22, as it combines four /24 subnets efficiently into a single route.
- A. Correct.
Correct. The /22 prefix aggregates the four /24 subnets (192.168.16.0 to 192.168.19.0) into a single summarized route.
- B. Incorrect.
Incorrect. A /23 prefix would only summarize two /24 subnets, not four.
- C. Incorrect.
Incorrect. A /20 prefix would include a much larger range of addresses than required, which is inefficient.
- D. Incorrect.
Incorrect. A /21 prefix would summarize a larger range of subnets, including addresses outside the given scope, which is not optimal.