300-420 Question 122
Single answerA network engineer is designing a large enterprise network. The network includes the following subnets: 192.168.4.0/24, 192.168.5.0/24, 192.168.6.0/24, and 192.168.7.0/24. To optimize routing table size and improve efficiency, the engineer decides to implement route summarization. Which summarized route should be advertised to the core network?
- A
192.168.4.0/22
- B
192.168.4.0/23
- C
192.168.0.0/21
- D
192.168.4.0/24
Show answer and explanation
Correct answer: A
Explanation
Route summarization is used to reduce the size of routing tables by advertising a single summarized route rather than multiple individual routes. The correct summarized route must include all the specified subnets without including unrelated subnets. In this case, 192.168.4.0/22 is the optimal summarization because it covers all the subnets (192.168.4.0/24 to 192.168.7.0/24) without overlapping with additional ranges.
- A. Correct.
Correct. The summarized route 192.168.4.0/22 encompasses all the given subnets (192.168.4.0/24, 192.168.5.0/24, 192.168.6.0/24, and 192.168.7.0/24) and optimally reduces the routing table size.
- B. Incorrect.
Incorrect. The route 192.168.4.0/23 only includes 192.168.4.0/24 and 192.168.5.0/24, but it does not cover 192.168.6.0/24 and 192.168.7.0/24.
- C. Incorrect.
Incorrect. The route 192.168.0.0/21 is too broad and would include additional subnets outside the intended range, leading to unnecessary advertisement of unrelated subnets.
- D. Incorrect.
Incorrect. The route 192.168.4.0/24 only includes a single subnet (192.168.4.0/24) and does not summarize the other subnets, failing to reduce the routing table size.