The network operation center is receiving an excessive number of BFD alerts.
This is due to recently configured high-speed links that result in BGP session teardown.
Engineers tried to modify the BFD timers, but no improvement was noticed.
Which action maximizes network stability?
Click on the arrows to vote for the correct answer
A. B. C. D.A.
https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r6-4/routing/configuration/guide/b-routing-cg-asr9000-64x/b-routing-cg-asr9000-BFD (Bidirectional Forwarding Detection) is a protocol used to detect failures in the forwarding path between two network nodes. It works by sending periodic hello packets between the nodes and measuring the round-trip time. If the round-trip time exceeds a configured threshold, BFD declares the path as failed and takes appropriate action, such as tearing down BGP sessions.
In this scenario, the excessive number of BFD alerts is most likely caused by the high-speed links that were recently configured. When a link is upgraded to a higher speed, the round-trip time of BFD packets may decrease significantly, causing BFD to declare the path as failed and tear down BGP sessions. This can cause instability in the network, as BGP sessions are critical for routing and forwarding traffic.
Modifying the BFD timers may not be effective in this case, as the problem is not with the BFD protocol itself but with the high-speed links. The IGP (Interior Gateway Protocol) hello timers are also unlikely to be the cause of the problem, as they are used to detect failures within a single routing domain, whereas BFD is used to detect failures between different domains.
Option A, enabling the BFD dampening feature, is a valid solution to this problem. BFD dampening is a mechanism that reduces the frequency of BFD alerts by delaying the detection of BFD failures. This can be useful in scenarios where BFD failures are caused by transient events, such as network congestion or link flapping. By delaying the detection of BFD failures, BFD dampening can help to reduce the number of BGP session teardowns and improve network stability.
Option B, fully removing the BFD configuration, is not recommended, as BFD is a useful protocol for detecting failures in the forwarding path. Removing the BFD configuration may leave the network vulnerable to undetected failures.
Option D, enabling the BGP dampening feature, is also a valid solution to this problem. BGP dampening is a mechanism that reduces the frequency of BGP updates by suppressing routes that are flapping (i.e., repeatedly going up and down). This can be useful in scenarios where BGP sessions are being torn down due to frequent route updates. However, BGP dampening may not be effective in scenarios where BGP sessions are being torn down due to BFD failures.
In summary, option A, enabling the BFD dampening feature, is the best solution to this problem, as it directly addresses the root cause of the excessive number of BFD alerts. Option D, enabling the BGP dampening feature, is also a valid solution, but may not be as effective in this particular scenario. Option B, fully removing the BFD configuration, is not recommended, as it leaves the network vulnerable to undetected failures. Option C, modifying the IGP hello timers, is unlikely to be effective in this case.