The word propagate doesn't imply an active push as opposed to a passive pull. The author made an assumption that is outside the definition of the word 'propagat

The word propagate doesn't imply an active push as opposed to a passive pull. The author made an assumption that is outside the definition of the word 'propagate'. Either way the new information propagates through the network. The 24-48 hour window should be the first hint that a slower passive method is being used.