300-420 Question 112
Select 3An enterprise network is experiencing high convergence times during a routing protocol failure. As a network engineer, you need to improve convergence across the network. Which of the following design considerations would most effectively reduce convergence times?
- A
Enable Bidirectional Forwarding Detection (BFD) on critical links.
- B
Increase the routing protocol timers (hello and dead timers) to reduce the frequency of updates.
- C
Implement Equal-Cost Multi-Path (ECMP) routing to provide redundant paths.
- D
Reduce the number of prefixes advertised by using route summarization.
- E
Deploy a flat Layer 2 network topology to minimize complexity.
Show answer and explanation
Correct answers: A, C, D
Explanation
To improve convergence times, design considerations such as enabling faster failure detection mechanisms like BFD, leveraging redundancy with ECMP, and simplifying routing tables with route summarization are critical. These techniques help ensure the network can react and recover quickly during failures. However, increasing routing protocol timers or relying on flat Layer 2 designs would hinder convergence performance.
- A. Correct.
Enabling BFD provides faster failure detection on links, which reduces the time needed for a routing protocol to react to a link failure.
- B. Incorrect.
Increasing routing protocol timers increases the time it takes to detect failures, which negatively impacts convergence times.
- C. Correct.
Implementing ECMP provides multiple redundant paths, enabling faster failover in case one path fails, thereby improving convergence.
- D. Correct.
Route summarization reduces the number of routes in the routing table, which simplifies recalculations during a failure, improving convergence time.
- E. Incorrect.
Deploying a flat Layer 2 topology increases broadcast domain size and can lead to scalability and convergence issues, especially in failure scenarios.