300-420 Question 85
Select 3A company is designing a new campus network and needs to ensure high availability and scalability in its Layer 2 infrastructure. Which design considerations should be implemented to achieve this goal?
- A
Implement Rapid PVST+ for faster convergence in spanning-tree topology.
- B
Use a Layer 2 loop-free topology by deploying Multi-Chassis EtherChannel (MEC).
- C
Deploy VLANs that span multiple access switches to simplify the configuration.
- D
Configure Per-VLAN Spanning Tree Instances (PVST+) on all switches to isolate VLAN failures.
- E
Use a hierarchical design with Access, Distribution, and Core layers.
Show answer and explanation
Correct answers: A, B, E
Explanation
To design a scalable and highly available Layer 2 campus infrastructure, it is critical to use best practices such as Rapid PVST+ for fast spanning-tree convergence, Multi-Chassis EtherChannel (MEC) for loop-free topologies and link aggregation, and a hierarchical design for fault isolation and scalability. Avoid spanning VLANs across multiple access switches to reduce failure domains and improve stability.
- A. Correct.
Implementing Rapid PVST+ improves spanning-tree convergence times, which enhances high availability in the Layer 2 infrastructure.
- B. Correct.
Using Multi-Chassis EtherChannel (MEC) eliminates Layer 2 loops and provides high availability and scalability by enabling link aggregation across multiple chassis.
- C. Incorrect.
Deploying VLANs that span multiple access switches can lead to larger failure domains and complicate troubleshooting, making it a poor design choice for scalability and availability.
- D. Incorrect.
Configuring Per-VLAN Spanning Tree Instances (PVST+) on all switches can isolate VLAN failures, but it can also increase the complexity of the spanning-tree topology and is not always necessary in modern designs.
- E. Correct.
A hierarchical design using Access, Distribution, and Core layers provides scalability, manageability, and fault isolation, which are essential for a high-performing campus network.