200-301 Question 302
Single answerA network administrator is configuring a router to use multiple routing protocols: OSPF, EIGRP, and static routes. When the router receives the same route from all three sources, which route will it choose to install in the routing table by default?
- A
The route learned via OSPF
- B
The route learned via EIGRP
- C
The route learned via the static route
- D
The route with the longest subnet mask
Show answer and explanation
Correct answer: C
Explanation
Administrative distance (AD) is a value that routers use to select the best route to install in the routing table when multiple routes to the same destination are learned from different sources. Lower AD values are preferred. Static routes have the lowest AD (1), followed by EIGRP (90) and OSPF (110). Therefore, when all three protocols provide the same route, the static route will be chosen by default.
- A. Incorrect.
OSPF has an administrative distance of 110, which is higher than EIGRP and static routes, so it will not be chosen in this scenario.
- B. Incorrect.
EIGRP has an administrative distance of 90, which is lower than OSPF but still higher than static routes, so the EIGRP route will not be chosen in this scenario.
- C. Correct.
Static routes have an administrative distance of 1 by default, which is the lowest compared to OSPF (110) and EIGRP (90). Therefore, the static route will be chosen and installed in the routing table.
- D. Incorrect.
The subnet mask does not determine the chosen route in this case. Instead, the route selection is based on the administrative distance.