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Date: Thu, 21 Apr 2005 23:09:45 +0200
From: Andre Oppermann <andre@freebsd.org>
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To: Rob <capveg@cs.umd.edu>
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cc: freebsd-hackers@freebsd.org
Subject: Re: FreeBSD Network Implementation Question
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Rob wrote:
> [applogies if this is in a FAQ somewhere... I've looked in a number of places, and
> am not able to find the answer]
> 
> Hi,
> 
> I am trying to figure out how large a specific buffer is in FreeBSD.
> The buffer in question is the buffer between the network layer and the
> ethernet device, i.e., if packets are being passed down the network
> stack from tcp faster than the hardware can handle them, at what point
> do packets start getting dropped locally?
> 
> I believe the answer is:
> 
> % sysctl -a
> [snip]
>  net.inet.ip.intr_queue_maxlen: 50
> 
> But try as I might, I can't find the documentation of the variable to
> confirm it.  Can anyone point me in the right direction?

You figured it out correctly.  However at that moment TCP flow control
would kick in and save you from local packet loss so to say.

-- 
Andre