I think we’re operating on different definitions of in-order and as received. TCP delivers packets in order, but perhaps not as received, if it had to request retransmission of a dropped packet. UDP delivers packets in order that they were received. Doing what the article suggests would make TCP also deliver packets in the order that they were received. No?
No problem, thanks for clarifying! So basically the benefit to the TCP NACK approach is that the TCP layer will also do a sort on the packets received?
Yeah, which is imperfect but there you are. It means sometimes out-of-order packets will be reordered, and sometimes dropped (since TCP acked it, the (existing) TCP code will discard the out-of-order packet as 'duplicate'. Which turns out works pretty well in practice, since out-of-order are almost always in a burst (no delay inter-packet)
