A water utility needs sub-second failure detection over a Metro-E handoff where shortening IGP hello timers alone is too blunt and CPU-heavy. Which mechanism best provides fast liveness detection for the routing adjacency?
Select an answer to reveal the explanation.
Short Explanation
BFD is the smoke detector that screams in milliseconds while the IGP is still sipping coffee on its hello schedule. You keep sane protocol timers and let BFD watch the pipe. When the Metro-E dies, routing gets the nudge almost immediately.
Full Explanation
BFD provides lightweight, rapid failure detection independent of aggressive hello tuning and can notify IGP sessions to tear down or fail over quickly. Stretching SPF throttles slows reaction, and disabling discovery protocols or changing AD does not create sub-second liveness on the link. For Metro-E and similar L2 handoffs, BFD is the standard EI pattern for fast detection.