300-420 Question 88
Select 3An enterprise network with 200 switches is experiencing slow convergence and scalability issues with Spanning Tree Protocol (STP). The network engineer is tasked with improving STP scalability without disrupting the entire network. Which of the following actions should the engineer take to address the issue?
- A
Enable Rapid PVST+ instead of traditional STP.
- B
Implement MST (Multiple Spanning Tree).
- C
Increase the max age timer for BPDU packets to reduce reconvergence frequency.
- D
Deploy Layer 3 routing to reduce the reliance on STP in the network.
- E
Disable STP on all links to eliminate topology recalculations.
Show answer and explanation
Correct answers: A, B, D
Explanation
To improve STP scalability in a large network, it is recommended to enable Rapid PVST+ for faster convergence, implement MST to reduce the number of STP instances, and consider deploying Layer 3 routing to limit the size of the Layer 2 domain. These approaches collectively address scalability and performance concerns without introducing additional risks. Increasing BPDU timers or disabling STP are not valid strategies as they can create new problems or fail to address the core issue.
- A. Correct.
Enabling Rapid PVST+ improves the convergence time and provides better scalability compared to traditional STP. However, this is a partial solution and additional changes may still be needed.
- B. Correct.
Implementing MST allows multiple VLANs to share a single spanning tree instance, significantly improving scalability by reducing the number of STP instances.
- C. Incorrect.
Increasing the max age timer for BPDU packets may delay convergence but does not address scalability issues. It is not a recommended practice for improving STP scalability.
- D. Correct.
Deploying Layer 3 routing reduces reliance on STP by segmenting the network into smaller broadcast domains and reducing the size of the Layer 2 domain. This enhances scalability and reduces STP complexity.
- E. Incorrect.
Disabling STP on all links is highly discouraged as it can lead to network loops and outages. This is not a valid solution for scalability issues.