Network Convergence Optimization: Remedying Slow Convergence in Case of PE Failure

Optimizing Network Convergence for Service Provider Engineer

Question

A service provider engineer enabled the BGP next-hop tracking feature and also tuned the OSPF to increase the network convergence in case of network failures.

However, the operator engineer notices that in cases of PE failure, the network convergence is still slow.

Which configuration must the operator use to remedy this failure scenario?

Answers

Explanations

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A. B. C. D.

D.

In this scenario, the service provider engineer has already enabled BGP next-hop tracking and tuned OSPF to increase network convergence in case of network failures. However, the operator engineer notices that in cases of PE failure, the network convergence is still slow. The operator needs to make a configuration change to remedy this failure scenario.

Answer choice A shows an OSPF configuration that always originates a default route into OSPF with a metric of 1, and sets timers for LSA and SPF throttling. While this configuration may improve convergence in some cases, it does not address the specific failure scenario described in the question.

Answer choice B shows a BGP configuration that uses a prefix list to match only /32 routes and a route map to match only OSPF routes. This configuration then sets the BGP next-hop to the selected route. While this configuration may improve convergence in some cases, it also does not address the specific failure scenario described in the question.

Answer choice C shows an OSPF configuration that disables default route origination and sets timers for LSA and SPF throttling. This configuration does not address the specific failure scenario described in the question.

Answer choice D shows a BGP configuration that enables next-hop trigger delay for both IPv4 and VPNv4 address families. This configuration enables BGP to proactively trigger next-hop updates upon detecting a failure, which can improve network convergence in case of a PE failure. Therefore, answer choice D is the correct configuration change that the operator engineer should use to remedy this failure scenario.

In summary, the correct answer is D because it enables BGP next-hop trigger delay, which helps to improve network convergence in the event of a PE failure.