Which BGP Dampening Config Fixes Routes Withdrawn From Peers?

300-410 By islever Editorial Last updated Oct 6, 2026

Troubleshoot BGP (Internal and External, unicast, and VRF-Lite) Troubleshoot network problems using Cisco Catalyst Center Assurance (formerly Cisco DNA Center) (connectivity, monitoring, device health, network health)

Short answer

A Enable bgp dampening globally under router bgp 100 so flapping BGP-learned networks are suppressed for all peers.

Question

Refer to the exhibit. In Cisco DNA Center, a network engineer identifies that BGP-learned networks are repeatedly withdrawn from peers. Which configuration must the engineer apply to resolve the issue? - Exhibit: Which BGP Dampening Config Fixes Routes Withdrawn From Peers?

Exhibit: Which BGP Dampening Config Fixes Routes Withdrawn From Peers?

router bgp 100 Correct Answer
router bgp 100
route-map Dampening permit 10
route-map Dampening permit 10

Key Takeaways

The question tests whether you can map the scope word "peers" to a process-wide BGP dampening configuration; the trap is choosing a neighbor-scoped dampening route-map that looks syntactically precise but only fixes one session.

This 300-410 exhibit question asks which configuration stops BGP-learned networks from being repeatedly withdrawn from peers, and the correct answer is the global bgp dampening command under router bgp 100 (A). The route-map Dampening option only dampens routes on a single neighbor, which does not match the plural scope in the stem.

Common mistake: Many candidates pick the route-map Dampening permit 10 option because the neighbor-level dampening syntax looks like a cleaner fix, but that route-map is attached inbound to one neighbor and cannot suppress flapping across every peer described in the question.

Expert Analysis

Why the Answer Is Correct

The stem states that BGP-learned networks are repeatedly withdrawn from peers, meaning the churn is observed across more than one BGP session, not just a single neighbor. Applying the bare "bgp dampening" command inside "router bgp 100" (option A) enables route dampening for the whole BGP process, so any flapping prefix received from those peers is suppressed after it crosses the suppress threshold instead of being continually re-advertised and withdrawn. The command also takes the default half-life, reuse, suppress and max-suppress values, so no extra parameters are required to make the configuration complete. The first exhibit shows exactly this global placement, while the second exhibit shows the neighbor-scoped alternative, making scope the deciding factor.

Why the Other Options Are Wrong

Option D uses "route-map Dampening permit 10" with a set dampening action attached to a specific neighbor, so it only affects the routes learned from that one session and leaves the other flapping peers untouched. Option C shows the same route-map construct and fails for the same reason: the stem talks about peers plural, and a single-neighbor remedy does not satisfy that scope. Option B, the second "router bgp 100" entry in the exhibit, does not match the global dampening behavior demonstrated for A and is not the configuration that suppresses flapping process-wide. Even the vote minority for D focused on syntax from a single-neighbor example rather than on the multi-peer wording, which is why the route-map variants lose.

Community Comment Notes

Most commenters chose A. As wwwwaaaa reasoned, A fits "just because of 'from peers' so not a single peer/route", implying the fix must be global rather than per-neighbor. NazgulNr5 echoed that the question says the problem occurs with 'peers' and noted that D "only applies to one neighbor", which is precisely the limitation the stem rules out. dapardo still preferred D and referenced a BGP route-dampening example, while Sammy3637 argued that the router bgp 100 variant is "close but incomplete" without threshold parameters. Despite that dissent, the thread converges on A because the exhibit's global dampening placement matches a multi-peer flapping scenario.

Official Reference

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/15-mt/irg-15-mt-book/irg-int-features.html

This link opens the official vendor documentation in a new tab.

Exam Strategy

When a BGP stem uses a plural scope word such as "peers", immediately eliminate any option that is attached to one specific neighbor and look for the command that enables the feature process-wide under router bgp. On exhibit questions, compare where the configuration is applied (router bgp versus neighbor) before comparing the damping parameters themselves.

Frequently Asked Questions

Why is a neighbor route-map with set dampening wrong for flapping peers?

The route-map is referenced inbound on one neighbor only, so it suppresses the flapping network on that session but not across all peers as the stem requires.

Does the bare 'bgp dampening' command need half-life and suppress thresholds?

No; the command uses defaults (15-minute half-life, 750 reuse, 2000 suppress, 60-minute max suppress), so option A is a complete, valid configuration.

More 300-410 FAQ →

Community Votes

73%

27%

73% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 8 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 8

wwwwaaaa 👍 3 Answered A

I will go with "A" just because of "from peers" so not a single peer/route plus, while "D" has the config correct, but we dont know if that flapping happening only on that one single neighbor
NazgulNr5 👍 3 Answered A

I say A because the question states the BGP problems occur with 'peers' not just one peer and D only applies to one neighbor.
dapardo 👍 2 Answered D

I agree with D, configuration seems to be right. Check this example: https://networklessons.com/bgp/bgp-route-dampening
Pietjeplukgeluk 👍 2 Answered A

Just because my other comment i will go for A (reasoning see other comment)
Sammy3637 👍 2 Answered A

Agree ! As it specifically asks for 'peers'

Show 3 more comments

tsamoko 👍 1 Answered A

100% A . Check the following links : 1) https://networklessons.com/bgp/bgp-route-dampening 2) https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/15-mt/irg-15-mt-book/irg-int-features.html#GUID-9CC2C114-3632-4D1D-9C92-8A1E4DF59061 3) https://networkengineering.stackexchange.com/questions/72994/change-bgp-dampening-parameters-for-a-specific-neighbor 4) https://networkengineering.stackexchange.com/questions/72994/change-bgp-dampening-parameters-for-a-specific-neighbor Furthermore , tested in GNS3 . A works fine . Tried to configure D , error shown "% "Dampening" used as BGP inbound route-map, set dampening not supported"
leipeG 👍 1

The correct answer is D because the issue in the question describes BGP routes being "repeatedly withdrawn." This typically indicates route flapping, where routes are constantly being advertised and withdrawn due to instability. BGP route dampening is used to reduce the impact of such instability by suppressing routes that are frequently flapping. Neighbor route-map Dampening in: The key here is applying the dampening "in", which applies it to the incoming routes from the neighbor. This helps prevent the local router from flapping routes and constantly withdrawing them from the peers.
Sammy3637 👍 1 Answered D

The command router bgp 100 bgp dampening is close but incomplete. To properly configure BGP dampening, you need to include the specific parameters for half-life, reuse-threshold, suppress-threshold, and max-suppress-time.

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