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350-401 · Question #876

Which of the following statements regarding the use of Bidirectional Forwarding Detection (BFD) in a Cisco SD-WAN environment are true?

The correct answer is A. BFD cannot be disabled on SD-WAN routers. C. In addition to link failure detection, it is also used to measure loss and latency used by application. In Cisco SD-WAN, BFD is inherently active on all tunnels and cannot be disabled, continuously measuring critical link characteristics like loss and latency for application-aware routing decisions.

Submitted by the_admin· Mar 6, 2026

Question

Which of the following statements regarding the use of Bidirectional Forwarding Detection (BFD) in a Cisco SD-WAN environment are true?

Options

  • ABFD cannot be disabled on SD-WAN routers.
  • BOSPFv3 is not supported with BFD.
  • CIn addition to link failure detection, it is also used to measure loss and latency used by application
  • DIs not typically enabled for OMP.
  • EDoes not support BGP.

How the community answered

(23 responses)
  • A
    87% (20)
  • B
    9% (2)
  • E
    4% (1)

Why each option

In Cisco SD-WAN, BFD is inherently active on all tunnels and cannot be disabled, continuously measuring critical link characteristics like loss and latency for application-aware routing decisions.

ABFD cannot be disabled on SD-WAN routers.Correct

BFD sessions are always-on and enabled by default on all tunnels between Cisco SD-WAN routers, providing continuous liveness detection and cannot be disabled.

BOSPFv3 is not supported with BFD.

BFD supports OSPFv3, allowing rapid detection of neighbor failures for IPv6 routing environments.

CIn addition to link failure detection, it is also used to measure loss and latency used by applicationCorrect

In addition to rapid link failure detection, BFD measures network performance metrics like loss and latency for each tunnel, which are crucial for the Cisco SD-WAN application-aware routing policies.

DIs not typically enabled for OMP.

BFD is typically enabled for OMP (Overlay Management Protocol) to rapidly detect neighbor reachability issues and ensure control plane stability.

EDoes not support BGP.

BFD supports BGP, enabling faster detection of BGP neighbor failures compared to reliance solely on BGP hold timers.

Concept tested: Cisco SD-WAN BFD characteristics

Source: https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/sdwan-xe-gs-book/m-monitor-troubleshoot.html

Topics

#BFD#Cisco SD-WAN#Network performance monitoring#Link failure detection

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