Re: TCP connection issues against Amazon S3
From: Rick Jones
Date: Thu Jan 08 2015 - 13:53:07 EST
Strange thing is that sender does not misbehave at the beginning when
receiver window is still small. Only after a while.
Just guessing, but when the receiver window is small, the sender cannot
get a large quantity of data out there at once, so any string of lost
packets will tend to be smaller. If the sender is relying on the RTO to
trigger the retransmits, and is not resetting his RTO until the clean
ACK of a segment sent after snd_nxt when the loss is detected, the
smaller loss strings will not get to the rather large RTO values seen in
the trace before curl gives-up. It may be that the sender is indeed
misbehaving at the beginning, just that it isn't noticeable?
Different but perhaps related observation/question - without timestamps
(which we don't have in this case), isn't there a certain ambiguity
about arriving out-of-order segments? One doesn't really know if they
are out-of-order because the network is re-ordering, or because they are
retransmissions of segments we've not yet seen at the receiver.
rick
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