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by JoeAltmaier 3059 days ago
TCP won't nack a packet when one is perceived as 'missed' (but really out-of-order); that's clear from the premise (ack everything).

But reordering also happens simply by examining received packets in a burst, and putting them right.

So its six of one and a half-dozen of the other I guess. Sorry for coming off so abrupt.
1 comments
ramzyo 3059 days ago
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?
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JoeAltmaier 3058 days ago
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)
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