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Date: Wed, 11 Feb 2004 14:50:49 +0100
From: Andre Oppermann <andre@freebsd.org>
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cc: Bjorn Eikeland <bjorn@eikeland.info>
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Subject: Re: dummynet = local taffic > 100ms - help!
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Richard Wendland wrote:
> 
> > It breaks TCP Timestamp generation slightly, but that's not likely to
> > break much of anything in practice.
> 
> Well, with HZ=10000 RFC1323 TCP connections will stop after 59.7 hours,
> with HZ=100000 after 6 hours.  For those with long running TCP connections
> (eg remote backup) that could be a big deal.  See 4.2.3 of RFC1323.
> 
> It does seem quite a few people want HZ>1000 so I think the time has
> come to isolate the TCP timestamp option clock from the HZ value to
> avoid this problem.  For now they should set net.inet.tcp.rfc1323=0 to
> avoid breaking RFC1323.
> 
> Note this doesn't affect routed packets, only TCP connections to/from
> that host.
> 
> Tom Pavel sent some patches to this list on 14 Jan 2004 that he has been
> using to overcome this HZ/RFC1323 problem.

I remember some comments (by BDE?) to the effect that the patch is not
entirely correct.

-- 
Andre