300-440 Question 60
Single answerA network engineer is configuring EIGRP in a network and needs to ensure that a backup route is available in case the primary route fails, without causing any routing loops. Which of the following conditions must be met for a route to be considered a feasible successor?
- A
The route's reported distance must be less than the current feasible distance of the successor route.
- B
The route's feasible distance must be equal to the feasible distance of the successor route.
- C
The route's reported distance must be equal to or greater than the feasible distance of the successor route.
- D
The route must have a higher administrative distance than the successor route.
Show answer and explanation
Correct answer: A
Explanation
In EIGRP, a feasible successor is a backup route that satisfies the condition RD < FD. This ensures that the backup route does not form a routing loop when it is used in the event of a failure of the primary (successor) route. The reported distance represents the metric advertised by the neighbor, and the feasible distance represents the best path to a destination. By maintaining RD < FD, EIGRP ensures loop-free alternate paths.
- A. Correct.
Correct. For a route to be considered a feasible successor in EIGRP, its reported distance (RD) must be less than the current feasible distance (FD) of the successor route. This ensures a loop-free topology.
- B. Incorrect.
Incorrect. The feasible distance of a feasible successor route is not required to be equal to the FD of the successor route. This is not a condition for loop-free path selection.
- C. Incorrect.
Incorrect. If the reported distance is equal to or greater than the feasible distance of the successor route, the route cannot be considered a feasible successor, as this would not guarantee a loop-free condition.
- D. Incorrect.
Incorrect. Administrative distance is not a factor in determining feasible successors in EIGRP. Feasible successors are based on the metrics like reported distance and feasible distance.