8 hours ago
The correct answer should be:
It has sub-second failure detection for layer 1 and layer 2 problems.
See this info from cisco's website to substantiate my above opinion above:
https://www.cisco.com/en/US/technologies...44005.html
CONCLUSION
Bidirectional Forwarding Detection provides a method for network administrators to configure sub-second Layer 2 failure detection between adjacent network nodes. Furthermore, they can configure their routing protocols to respond to BFD notifications, and begin Layer 3 route convergence almost immediately.
It has sub-second failure detection for layer 1 and layer 2 problems.
See this info from cisco's website to substantiate my above opinion above:
https://www.cisco.com/en/US/technologies...44005.html
CONCLUSION
Bidirectional Forwarding Detection provides a method for network administrators to configure sub-second Layer 2 failure detection between adjacent network nodes. Furthermore, they can configure their routing protocols to respond to BFD notifications, and begin Layer 3 route convergence almost immediately.