300-410 Question 7
Single answerA network engineer is troubleshooting a route selection issue in a multi-protocol environment. OSPF, EIGRP, and a static route to the same destination network (10.1.1.0/24) are configured on the router. The static route has an administrative distance of 1, OSPF has an administrative distance of 110, and EIGRP has an administrative distance of 90. Despite the EIGRP route being preferred based on administrative distance, traffic is still using the static route. What could be the reason for this behavior?
- A
The static route has the lowest administrative distance and will always be preferred.
- B
The static route is configured with a longer prefix length than the EIGRP and OSPF routes.
- C
The static route is incorrectly configured with a higher metric than the EIGRP route.
- D
The static route is redistributed into EIGRP, causing a conflict in route selection.
Show answer and explanation
Correct answer: A
Explanation
Administrative distance determines the trustworthiness of a route source. Lower administrative distances are preferred over higher ones. In this case, the static route has the lowest administrative distance (1) compared to EIGRP (90) and OSPF (110), so it is selected for forwarding traffic to the destination network, regardless of the metrics or routing protocols involved.
- A. Correct.
Correct. The static route has the lowest administrative distance (1), which means it will always be preferred over any dynamic routing protocol (like EIGRP or OSPF) for the same destination network.
- B. Incorrect.
Incorrect. Prefix length does not impact route selection in this scenario since all routes point to the same destination network (10.1.1.0/24). Administrative distance is the deciding factor here.
- C. Incorrect.
Incorrect. A static route does not use metrics for decision-making. Administrative distance is the primary factor for route selection in this case.
- D. Incorrect.
Incorrect. While redistribution can cause conflicts, it is not relevant here because the static route is not being redistributed into EIGRP.