300-420 Question 123
Single answerAn enterprise network has multiple branch offices connected to the headquarters using static routes. The branch offices use the IP address range 10.10.0.0/24 to 10.10.7.0/24. The network administrator wants to configure route summarization to optimize the routing table at the headquarters. Which summarized route should the administrator configure?
- A
10.10.0.0/21
- B
10.10.0.0/22
- C
10.10.0.0/23
- D
10.10.0.0/20
Show answer and explanation
Correct answer: A
Explanation
Route summarization reduces the number of routes in the routing table by combining multiple specific routes into a single summarized route. In this scenario, the branch offices use the range 10.10.0.0/24 to 10.10.7.0/24, which can be summarized as 10.10.0.0/21. This summarized route efficiently represents all the required subnets without including unnecessary address space.
- A. Correct.
This is the correct summarized route because 10.10.0.0/21 covers the range from 10.10.0.0 to 10.10.7.255, which includes all the branch office subnets.
- B. Incorrect.
10.10.0.0/22 only covers the range 10.10.0.0 to 10.10.3.255, which is insufficient to encompass all branch office subnets.
- C. Incorrect.
10.10.0.0/23 only covers the range 10.10.0.0 to 10.10.1.255, which is insufficient to encompass all branch office subnets.
- D. Incorrect.
10.10.0.0/20 covers the range 10.10.0.0 to 10.10.15.255, which is too broad and includes unnecessary IP address space outside the branch office subnets.