A company with multiple service providers wants to speed up BGP convergence time in the event a failure occurs with their primary link.
Which approach achieves this goal and does not impact router CPU utilization?
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A. B. C. D.C.
BGP convergence time refers to the time it takes for BGP routers to detect a network failure and to update their routing tables accordingly. This can be critical for companies that rely on their network connectivity to conduct their business.
Of the options presented, option A, which is to utilize Bidirectional Forwarding Detection (BFD) and tune the multiplier to 50, is the best approach to speed up BGP convergence time without impacting router CPU utilization.
BFD is a protocol that detects failures in the forwarding path between two routers and can quickly notify the routers of the failure. It is a low-overhead protocol that can work with a variety of routing protocols, including BGP, and can provide sub-second failure detection. By using BFD with a multiplier of 50, BGP can quickly detect a network failure and converge to a new routing path.
Option B, lowering the BGP hello interval, could potentially speed up convergence time, but it would also increase the overhead on the router's CPU, as it would need to send more hello packets. This could impact the overall performance of the router and potentially lead to other issues.
Option C, decreasing the BGP keepalive timer, would also increase the overhead on the router's CPU and could lead to other issues. Keepalive messages are used to maintain the BGP session between two routers, and decreasing the timer could cause unnecessary session resets.
Option D, utilizing BFD and keeping the default BGP timers, is a good option, but it is not as effective as tuning the BFD multiplier to 50. The default BGP timers are designed to balance the need for fast convergence with the overhead on the router's CPU, but they may not be sufficient for a company that requires sub-second convergence times.
In summary, the best approach to speed up BGP convergence time without impacting router CPU utilization is to utilize BFD and tune the multiplier to 50.