H12-821_V1.0 · Question #818
In order to ensure that both systems know the status changes, BFD uses a three-way handshake mechanism when establishing and tearing down the BFD state machine.
The correct answer is A. TRUE. Option A is correct because BFD (Bidirectional Forwarding Detection) explicitly uses a three-way handshake during session establishment and teardown, cycling through three states - Down → Init → Up - to guarantee that both peers have acknowledged the state transition before…
Question
Options
- ATRUE
- BFALSE
How the community answered
(29 responses)- A72% (21)
- B28% (8)
Explanation
Option A is correct because BFD (Bidirectional Forwarding Detection) explicitly uses a three-way handshake during session establishment and teardown, cycling through three states - Down → Init → Up - to guarantee that both peers have acknowledged the state transition before considering the session fully active or terminated.
Option B (FALSE) is wrong because BFD's RFC 5880 specification defines this three-way mechanism as a core requirement; a two-way or unilateral state change would risk one peer believing a session is active while the other considers it down, defeating BFD's purpose of fast, reliable failure detection.
Memory tip: Think "BFD = Three letters, three states, three-way handshake." The three BFD session states (Down, Init, Up) map directly to the three steps of the handshake - when you remember one, you remember all.
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