300-420 Question 20
Select 3You are tasked with designing an OSPF routing solution for a large enterprise network that spans multiple geographical locations. The network consists of multiple branch offices connected to two core data centers. It is critical to ensure that the OSPF design is scalable, minimizes the risk of routing instability, and ensures efficient use of resources. Which of the following design considerations should you implement?
- A
Use OSPF areas to segment the network and limit the size of LSDBs (Link-State Databases).
- B
Deploy OSPF in a single area across the entire enterprise for simplicity.
- C
Configure one of the core data centers as an OSPF backbone (Area 0) and use area summarization to reduce routing overhead.
- D
Use OSPF stub or totally stubby areas for branch offices to limit external routing information.
- E
Disable OSPF cost metrics to simplify routing decisions and reduce administrative overhead.
Show answer and explanation
Correct answers: A, C, D
Explanation
A scalable, stable, and secure OSPF routing design incorporates hierarchical structuring using areas to reduce LSDB size, uses summarization to reduce routing overhead, and leverages stub areas to limit unnecessary routing information in branch offices. These practices ensure efficient use of resources and minimize the risk of routing instability.
- A. Correct.
Using OSPF areas to segment the network is a best practice for scalability and stability. It limits the size of LSDBs, reducing the processing burden on routers.
- B. Incorrect.
Using a single OSPF area for the entire enterprise is not scalable. It increases the size of LSDBs and makes troubleshooting and convergence more complex.
- C. Correct.
Designating one of the core data centers as Area 0 (the backbone) and using area summarization minimizes routing overhead and enhances scalability.
- D. Correct.
OSPF stub or totally stubby areas are effective in branch office designs where external routing information is not required, reducing unnecessary routing updates.
- E. Incorrect.
Disabling OSPF cost metrics is not recommended as it eliminates the ability to prioritize paths and may lead to suboptimal routing.