This read-write INTEGER (5-300), defaulting to 5, sets the neighbor discovery time in the now-deprecated ULD feature; once this discovery period ends, active unidirectional link detection begins on the interface. An admin tunes it to control how long the switch waits to learn about its neighbor before starting to actively test link directionality. Increasing eltULDDiscoveryTime beyond the default 5 gives more time for neighbor discovery on a link with a slow-to-respond peer before ULD starts making detection decisions.