300-420 Question 109
Single answerA company has two campuses connected through an MPLS backbone. Each campus has its own set of VLANs and routing domains. The design requires seamless Layer 3 communication between the campuses while ensuring scalability and optimized routing. Which design approach should be implemented?
- A
Deploy an EIGRP routing protocol with mutual redistribution at the MPLS edge routers.
- B
Use BGP as the routing protocol with route reflectors in each campus.
- C
Implement OSPF with area 0 spanning both campuses through the MPLS backbone.
- D
Configure static routes between the campuses on the MPLS edge routers.
Show answer and explanation
Correct answer: C
Explanation
For multi-campus Layer 3 infrastructures, OSPF with area 0 spanning across the campuses ensures a scalable and efficient routing design. It allows for dynamic route updates, fast convergence, and a hierarchical structure, making it a preferred choice for such scenarios over static routes or overly complex protocols like BGP.
- A. Incorrect.
EIGRP can support campus communication; however, mutual redistribution can lead to challenges such as routing loops or suboptimal routing in larger, multi-campus topologies.
- B. Incorrect.
BGP is typically used for external or large-scale routing scenarios. While it can work, it introduces unnecessary complexity for intra-campus routing unless there is a specific need for BGP, such as policy-based routing.
- C. Correct.
OSPF with area 0 spanning both campuses through the MPLS backbone ensures a scalable, hierarchical design. It provides fast convergence and optimized routing while maintaining simplicity and scalability.
- D. Incorrect.
Static routes are not scalable for multi-campus designs and require manual updates whenever there are topology changes, making them unsuitable for dynamic environments.