200-301 Question 271
Single answerA network administrator is tasked with summarizing the following IPv4 prefixes into a single route: 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 they 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
Summarization combines multiple prefixes into a single, more efficient route. The prefixes in this scenario (192.168.0.0/24, 192.168.1.0/24, 192.168.2.0/24, and 192.168.3.0/24) can be summarized as 192.168.0.0/22 because this prefix covers all the given addresses while minimizing the routing table size. Choosing a broader or narrower range would either include unnecessary addresses or fail to cover the entire range.
- A. Correct.
Correct. The 192.168.0.0/22 prefix includes the range 192.168.0.0 to 192.168.3.255, which covers all the given prefixes. Summarizing these into a /22 prefix minimizes the routing table size.
- B. Incorrect.
Incorrect. The 192.168.0.0/23 prefix only covers 192.168.0.0 to 192.168.1.255 and does not include the entire range of the given prefixes.
- C. Incorrect.
Incorrect. The 192.168.0.0/21 prefix covers a larger range (192.168.0.0 to 192.168.7.255), which includes unnecessary addresses that go beyond the given prefixes, making it less efficient.
- D. Incorrect.
Incorrect. The 192.168.1.0/22 prefix starts at 192.168.1.0 and includes 192.168.1.0 to 192.168.4.255, missing 192.168.0.0/24 entirely.