5 ms·

See my answer to WJW above. Yes, even in the face of network partition, but with system unavailability in the event of a network partition.

• WJW 6y ago
  System unavailability means the messages get delivered zero times, which is not exactly once.
• sagichmal 6y ago
  So we're just playing semantic games at this point, using different definitions of terms. The definition of "exactly once" you're using isn't the formal definition.