From: Rick Jones <rick.jones2@hp.com>
To: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: noboru.obata.ar@hitachi.com, David Miller <davem@davemloft.net>,
yoshfuji@linux-ipv6.org, netdev@vger.kernel.org
Subject: Re: [PATCH 2.6.22] TCP: Make TCP_RTO_MAX a variable (take 2)
Date: Thu, 12 Jul 2007 14:27:05 -0700 [thread overview]
Message-ID: <46969CA9.8030406@hp.com> (raw)
In-Reply-To: <20070712141203.7350429a@freepuppy.rosehill.hemminger.net>
> One question is why the RTO gets so large that it limits failover?
>
> If Linux TCP is working correctly, RTO should be srtt + 2*rttvar
>
> So either there is a huge srtt or variance, or something is going
> wrong with RTT estimation. Given some reasonable maximums of
> Srtt = 500ms and rttvar = 250ms, that would cause RTO to be 1second.
I suspect that what is happening here is that a link goes down in a
trunk somewhere for some number of seconds, resulting in a given TCP
segment being retransmitted several times, with the doubling of the RTO
each time.
rick jones
next prev parent reply other threads:[~2007-07-12 21:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-12 7:15 [PATCH 2.6.22] TCP: Make TCP_RTO_MAX a variable (take 2) OBATA Noboru
2007-07-12 9:37 ` David Miller
2007-07-12 13:59 ` OBATA Noboru
2007-07-12 20:24 ` David Miller
2007-07-12 21:12 ` Stephen Hemminger
2007-07-12 21:27 ` Rick Jones [this message]
2007-07-12 22:02 ` Stephen Hemminger
2007-07-12 22:27 ` Rick Jones
2007-07-24 13:30 ` OBATA Noboru
2007-07-13 4:29 ` Ilpo Järvinen
2007-07-13 16:55 ` Rick Jones
2007-07-14 6:19 ` David Miller
2007-07-23 18:40 ` Rick Jones
[not found] ` <20070828.220447.01366772.noboru.obata.ar@hitachi.com>
[not found] ` <20070828.133057.107937654.davem@davemloft.net>
2007-08-29 12:26 ` OBATA Noboru
2007-08-29 16:16 ` Rick Jones
2007-08-30 12:24 ` OBATA Noboru
2007-08-29 18:15 ` David Miller
2007-07-12 20:51 ` Rick Jones
2007-07-24 13:35 ` OBATA Noboru
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