From: kuznet@ms2.inr.ac.ru
To: lk@tantalophile.demon.co.uk (Jamie Lokier)
Cc: davem@redhat.com, ak@muc.de, linux-kernel@vger.kernel.org
Subject: Re: Excessive TCP retransmits over lossless, high latency link
Date: Sat, 1 Sep 2001 22:08:24 +0400 (MSK DST) [thread overview]
Message-ID: <200109011808.WAA19782@ms2.inr.ac.ru> (raw)
In-Reply-To: <20010901181729.A2204@thefinal.cern.ch> from "Jamie Lokier" at Sep 1, 1 06:17:29 pm
Hello!
> The interesting thing is that there isn't any evidence of packet loss.
Why did you disable bith sacks and timestamps? Exactly to get
maximal damage from long delay link?
> Is there some /proc/sys setting to fix this, a kernel patch, or is it
> perhaps fixed in a newer kernel already?
No patches to block send required ACKs exist of course. :-)
All the problem is at sender, it mispredicts rtt.
What OS is sender? If it is linux too, try to use default configuration
not playing with /proc/sys/net/tcp_*, especially with timestamps
and sacks and the situation should rectify.
Also, please, send full (binary!) tcpdump from SYN and to FIN.
Andi says right thing, but I am still puzzled why rtt is miscalculated
it should be estimated correctly.
Well, and if sender is not linux... no ideas.
Alexey
next prev parent reply other threads:[~2001-09-01 18:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-01 17:17 Excessive TCP retransmits over lossless, high latency link Jamie Lokier
2001-09-01 17:41 ` Andi Kleen
2001-09-01 18:12 ` kuznet
2001-09-01 18:22 ` Jamie Lokier
2001-09-01 19:07 ` Neil Spring
2001-09-01 18:08 ` kuznet [this message]
2001-09-01 18:55 ` Jamie Lokier
2001-09-01 19:20 ` kuznet
2001-09-01 20:02 ` Jamie Lokier
2001-09-01 20:39 ` Lukas Beeler
2001-09-03 17:14 ` kuznet
2001-09-03 17:57 ` Jamie Lokier
2001-09-03 18:07 ` kuznet
2001-09-01 19:59 ` Alan Cox
[not found] <20010901195532.B2714@thefinal.cern.ch.suse.lists.linux.kernel>
[not found] ` <200109011920.XAA20031@ms2.inr.ac.ru.suse.lists.linux.kernel>
[not found] ` <20010901210212.A3361@thefinal.cern.ch.suse.lists.linux.kernel>
[not found] ` <20010901223918.A4053@mail.projectdream.org.suse.lists.linux.kernel>
2001-09-01 21:45 ` Andi Kleen
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