300-420 Question 19
Select 3You are designing an OSPF routing architecture for a large enterprise network that consists of multiple locations. Each location is connected via dedicated WAN links, and the network must support scalability, stability, and security. Which of the following design choices would best meet these requirements?
- A
Implement OSPF multi-area design with a dedicated Area 0 (backbone area).
- B
Use OSPF Stub or Totally Stubby Areas for remote branch locations with limited routing requirements.
- C
Enable OSPF authentication to secure routing updates between OSPF neighbors.
- D
Configure all devices in the network to belong to a single OSPF area for simplified management.
- E
Use external type-2 (E2) routes for all redistributed routes to reduce complexity in the OSPF domain.
Show answer and explanation
Correct answers: A, B, C
Explanation
An optimal OSPF routing design for large enterprise networks should focus on scalability, stability, and security. Multi-area OSPF design with a dedicated backbone area (Area 0) ensures scalability and isolates topology changes. Stub or Totally Stubby Areas reduce routing table size and resource utilization for branch locations, improving stability. Enabling authentication secures routing updates. While a single-area design simplifies management, it sacrifices scalability in large networks. Similarly, using E2 routes may reduce redistribution complexity but does not address the core requirements of scalability, stability, or security.
- A. Correct.
Implementing OSPF multi-area design with a dedicated Area 0 ensures scalability and stability by limiting the impact of topology changes to specific areas, while Area 0 serves as the backbone for inter-area communication.
- B. Correct.
Using OSPF Stub or Totally Stubby Areas for remote branch locations minimizes routing table size and reduces resource utilization, enhancing scalability and stability in the network.
- C. Correct.
Enabling OSPF authentication ensures routing updates are secured, protecting the network from unauthorized changes and enhancing security.
- D. Incorrect.
Configuring all devices in a single OSPF area can simplify management but compromises scalability and stability in large networks as topology changes propagate to all devices.
- E. Incorrect.
Using external type-2 (E2) routes for all redistributed routes can reduce complexity for redistribution but does not directly contribute to scalability, stability, or security in the OSPF design.