300-420 Question 115
Select 3An enterprise network has recently undergone a topology change due to a link failure. The network uses OSPF as its routing protocol. The network administrator observes that some routes take longer to converge than expected. Which of the following factors could contribute to the delayed convergence in this scenario?
- A
The OSPF Hello and Dead timers are misconfigured.
- B
A high number of LSA updates are being generated and processed in the network.
- C
The OSPF area design includes a single, flat area for the entire network.
- D
The network is configured to use OSPF Stub areas where possible.
- E
The CPU utilization on key routers is consistently high during the convergence process.
Show answer and explanation
Correct answers: A, B, E
Explanation
Convergence in OSPF can be delayed by factors that slow down the detection of topology changes or the processing of SPF calculations. Misconfigured timers, excessive LSA flooding, and high CPU utilization are all potential causes of delayed convergence. Proper configuration and network design can help mitigate these issues and ensure faster convergence.
- A. Correct.
Misconfigured OSPF Hello and Dead timers can delay the detection of link failures, which slows down convergence.
- B. Correct.
A high number of LSA updates can overwhelm routers, delaying the SPF calculations and convergence process.
- C. Incorrect.
While a single, flat OSPF area can lead to scalability challenges, it does not directly cause delayed convergence in this scenario.
- D. Incorrect.
Using OSPF Stub areas typically reduces complexity and LSA flooding, which should improve convergence rather than delay it.
- E. Correct.
High CPU utilization during the convergence process can slow down SPF calculations and the application of new routes, delaying convergence.