200-301 Question 272
Single answerA network engineer is tasked with summarizing the following IPv4 subnets into a single prefix: 192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24. Which summarized prefix should the engineer use?
- A
192.168.0.0/22
- B
192.168.0.0/23
- C
192.168.0.0/21
- D
192.168.1.0/22
Show answer and explanation
Correct answer: A
Explanation
To summarize multiple subnets into a single prefix, you need to find the smallest prefix that encompasses all the given subnets. The four /24 subnets (192.168.0.0, 192.168.1.0, 192.168.2.0, 192.168.3.0) can be represented by a single prefix of 192.168.0.0/22. This ensures efficient routing while including all the required subnets.
- A. Correct.
Correct. The /22 prefix aggregates all four /24 subnets (192.168.0.0 to 192.168.3.0) into a single summarized route. A /22 prefix covers 1024 IP addresses, which includes the range from 192.168.0.0 to 192.168.3.255.
- B. Incorrect.
Incorrect. A /23 prefix would only summarize two /24 subnets, such as 192.168.0.0/24 and 192.168.1.0/24, but not all four.
- C. Incorrect.
Incorrect. A /21 prefix would cover a larger range than necessary, aggregating eight /24 subnets (192.168.0.0 to 192.168.7.0), which is beyond the required range.
- D. Incorrect.
Incorrect. A /22 prefix starting at 192.168.1.0 would summarize the range from 192.168.1.0 to 192.168.4.255, which does not include the 192.168.0.0/24 subnet.