300-320 · Question #359
A company is running BGP on the edge with multiple service providers in a primary and secondary role. The company wants to speed up time if a failure were to occur with the primary, but they are…
The correct answer is D. Utilize BFD and keep the default BGP timers. BFD (Bidirectional Forwarding Detection) is a lightweight, hardware-assisted sub-second failure detection protocol. By enabling BFD alongside BGP and keeping the default BGP timers (D), the network achieves fast failover detection (BFD detects failures in milliseconds) without…
Question
A company is running BGP on the edge with multiple service providers in a primary and secondary role. The company wants to speed up time if a failure were to occur with the primary, but they are concerned about router resources. Which method best achieves this goal?
Options
- AUtilize BFD and lower BGP hello interval
- BDecrease the BGP keepalive timer
- CUtilize BFD and tune the multiplier to 50
- DUtilize BFD and keep the default BGP timers
How the community answered
(42 responses)- A10% (4)
- B5% (2)
- C21% (9)
- D64% (27)
Explanation
BFD (Bidirectional Forwarding Detection) is a lightweight, hardware-assisted sub-second failure detection protocol. By enabling BFD alongside BGP and keeping the default BGP timers (D), the network achieves fast failover detection (BFD detects failures in milliseconds) without the resource cost of aggressively tuned BGP timers. BFD offloads the detection work to the forwarding plane, preserving CPU resources on the router. Choice A is suboptimal because lowering the BGP hello interval increases BGP-related CPU overhead. Choice B also increases CPU load by forcing more frequent keepalive processing. Choice C is incorrect because a BFD multiplier of 50 would make BFD extremely slow to detect failures, defeating its purpose-typical values are 3–5.
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