350-401 Question 414
Single answerAn enterprise network uses OSPF as its IGP. The network administrator notices suboptimal routing due to OSPF preferring a path with lower bandwidth over a path with higher bandwidth. Which action should the administrator take to resolve this issue?
- A
Adjust the OSPF cost on the interfaces of the higher bandwidth path.
- B
Reconfigure OSPF to use EIGRP as the routing protocol.
- C
Modify the OSPF administrative distance to prioritize the higher bandwidth path.
- D
Enable OSPF auto-cost reference bandwidth to properly scale for higher-speed links.
Show answer and explanation
Correct answer: D
Explanation
By default, OSPF uses a reference bandwidth of 100 Mbps to calculate interface costs, which can lead to suboptimal routing on modern high-speed links (e.g., 1 Gbps or 10 Gbps). Enabling OSPF auto-cost reference bandwidth allows the administrator to adjust the reference bandwidth to match the current network infrastructure, ensuring that OSPF accurately calculates metrics and selects optimal paths.
- A. Incorrect.
Adjusting the OSPF cost manually on interfaces could resolve the issue, but it is not the most scalable or efficient solution, especially in large networks with multiple high-speed links.
- B. Incorrect.
Reconfiguring OSPF to use EIGRP would replace the routing protocol entirely, which is not a practical solution for addressing metrics in OSPF.
- C. Incorrect.
The OSPF administrative distance is used to compare OSPF routes with routes from other protocols, not to influence the selection of routes within OSPF itself.
- D. Correct.
Enabling OSPF auto-cost reference bandwidth ensures that OSPF appropriately calculates costs for high-speed links, resolving the issue of suboptimal routing caused by outdated bandwidth metrics.