Date: Thu, 05 Apr 2018 20:46:23 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-net@FreeBSD.org Subject: [Bug 227303] tcp cwnd grows without bounds while app/rwnd limited, interacts badly with rwnd autosize Message-ID: <bug-227303-2472-StDcHsx8Cm@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-227303-2472@https.bugs.freebsd.org/bugzilla/> References: <bug-227303-2472@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D227303 --- Comment #2 from Richard Scheffenegger <srichard@netapp.com> --- After further investigation, this issue is more complex. cwnd does in fact = not grow when the transmission is rwnd limited. However, 20 sec prior to these = two burst events, during slow start, the client already signaled a large rwnd (= at least as large as when the bursts happen). And no losses occured, so cwnd d= id probably grow to the large rwnd (or very close to is) during the initial sl= ow start. Then, the client reduced rwnd to 1/2 or 1/3 of that initial value, a= nd cwnd never decays (RTT is 1ms with empty buffers, and 40ms with full buffer= s; 20 sec are eons in any case).=20 So at the time of these graphs, cwnd has no longer any valid information ab= out the state of the network, but is nevertheless used as such. Guess RFC7661 (with substituting "no transmissions" with "transmission rate= < cwnd") with it's many-rtt long decay would adress this particular issue. Can provide xpl file (but not original trace) of the entire session. --=20 You are receiving this mail because: You are the assignee for the bug.=
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