[lisper]

> Delivery is what happens when the signals cross from the wire into the network interface card.

If you look at this sibling comment [1] you will find someone who disagrees with your definition.

[1] https://news.ycombinator.com/item?id=41601562

On your definition, yes, exactly-once delivery is not possible. But I think your definition is neither reasonable nor authoritative.

[srkiNZ]

FWIW, I consider that definition to be both reasonable and (in the context of "distributed systems") authoritative.