200-301 Question 286
Single answerA network engineer is troubleshooting the routing table of a router running OSPF in a multi-area network. The engineer notices that one route is preferred over another, despite both routes leading to the same destination. What could be the reason for this behavior?
- A
The route with the lower OSPF metric is selected.
- B
The route with the higher administrative distance is selected.
- C
The route with the lower bandwidth is selected.
- D
The route with the higher OSPF area ID is selected.
Show answer and explanation
Correct answer: A
Explanation
In OSPF, the route metric is calculated using the cost, which is inversely proportional to the bandwidth of the links. OSPF always prefers the route with the lowest cost/metric to reach a destination. Administrative distance and area ID do not influence route selection within OSPF.
- A. Correct.
Correct: OSPF uses a metric based on cost, which is calculated from the bandwidth of the links. The route with the lower metric (cost) is preferred.
- B. Incorrect.
Incorrect: OSPF routes have a fixed administrative distance of 110. Administrative distance is used for route selection between different routing protocols, not within OSPF itself.
- C. Incorrect.
Incorrect: OSPF does not directly select routes based on lower bandwidth. Instead, it calculates the cost of a route using the inverse of bandwidth and selects the route with the lower metric.
- D. Incorrect.
Incorrect: OSPF area IDs are not used to determine the preferred route. They are used to organize and structure the OSPF network.