200-301 Question 308
Single answerA network engineer is troubleshooting routing issues in a network where multiple routing protocols are implemented. They notice that a route learned via OSPF (metric: 20) is not being used, while a route to the same destination learned via EIGRP (metric: 1500) is preferred. What could be the reason for this behavior?
- A
EIGRP has a lower administrative distance than OSPF.
- B
OSPF has a lower administrative distance than EIGRP.
- C
The OSPF metric is higher than the EIGRP metric.
- D
The EIGRP metric is not being calculated correctly.
Show answer and explanation
Correct answer: A
Explanation
Administrative distance is the deciding factor when a router learns routes to the same destination from multiple routing protocols. EIGRP's default administrative distance (90) is lower than OSPF's default administrative distance (110), meaning the route from EIGRP is preferred over OSPF, regardless of the metric values.
- A. Correct.
Correct. EIGRP has a default administrative distance of 90, which is lower than OSPF's default administrative distance of 110. When two routes to the same destination exist, the router will prefer the route with the lower administrative distance, regardless of the metric.
- B. Incorrect.
Incorrect. While OSPF uses a lower metric in this scenario, the administrative distance determines which routing protocol's route is preferred, not just the metric.
- C. Incorrect.
Incorrect. The OSPF metric of 20 is actually lower than the EIGRP metric of 1500, but metrics are protocol-specific and cannot be compared across different routing protocols.
- D. Incorrect.
Incorrect. The EIGRP metric is calculated correctly based on bandwidth and delay. The issue lies in the administrative distance comparison, not the metric calculation.