Thanks for the trace!
AFAICT there seems to be a bug in the tshark tool, where for some packets that
should be deemed retransmits, it marks them as merely "Out-Of-Order" instead.
For example, it is declaring this an out-of-order packet, when it
should be marked
8212 0.404242 10.0.0. 10.0.0.50 TCP 1514 [TCP Out-Of-Order]
6666 [ACK] Seq=308425 Ack=1 Win=65536 Len=1448 TSval=151696734
From the tcpdump output we can see that the packet is a retransmit:
Here is the original offload burst of 3*MSS:
09:32:21.763592 IP 10.0.0.7.39860 > 10.0.0.50.6666: Flags [P.],
seq 306976:311320, ack 1, win 64, options [nop,nop,TS val 151696674
], length 4344
And here is the retransmit of 1MSS at 308424:309872:
09:32:21.822726 IP 10.0.0.7.39860 > 10.0.0.50.6666: Flags [.], seq
308424:309872, ack 1, win 64, options [nop,nop,TS val 151696734 ecr
], length 1448
My guess would be that this is why the not-ECT packets count is 10x
higher than the
So I still have the same theory that I noted above. I will try to prepare a fix
and follow up in this thread when it is ready for testing.
On Sat, Mar 14, 2020 at 5:57 PM Fejes Ferenc