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Date: Tue, 12 Jul 2005 16:49:25 +0300
From: Giorgos Keramidas <keramida@freebsd.org>
To: Roman Kurakin <rik@cronyx.ru>
Message-ID: <20050712134925.GB1061@beatrix.daedalusnetworks.priv>
References: <42D3B9A8.6000803@cronyx.ru>
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Cc: freebsd-net@freebsd.org
Subject: Re: ping delay, initial request
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On 2005-07-12 16:38, Roman Kurakin <rik@cronyx.ru> wrote:
> Hi,
> 
>    I am starting to investigate some net problem and I wonder if this
> problem seen/known.
>    The problem was observed with ce(4) (Cronyx Tau32-PCI/Lite,
> it is not in the tree yet, but similar to cp(4)/ctau(4) devices) and 
> sppp(4).
> If you run usual ping you will see normal delay which is much less than 
> 1sec.
> But if you run flood ping, stop it, and run normal ping again you'll see 
> delay
> about one sec.
> 
> ping x.x.x.x
> delay << 1 sec
> ping -f x.x.x.x
> average delay << 1 sec
> ping x.x.x.x
> delay ~ 1 sec
> 
> This was seen on FreeBSD 4.11 stable.
> 
> Any ideas? Does any body observed such behaviour in other environment?

Is it possible that flood ping hits an icmp rate-limiting watermark and
then every subsequent icmp packet gets penalized with a delay until a
fair amount of time passes?