From owner-freebsd-net  Wed Jun 27 21:34:54 2001
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Date: Wed, 27 Jun 2001 22:39:20 -0600
From: Wes Peters <wes@softweyr.com>
Organization: Softweyr LLC
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To: Ruslan Ermilov <ru@FreeBSD.org>
Cc: Deepak Jain <deepak@ai.net>, net@FreeBSD.org, hackers@FreeBSD.org
Subject: Re: fastforwarding?
References: <GPEOJKGHAMKFIOMAGMDICEOJDGAA.deepak@ai.net> <20010626093545.D49992@sunbay.com>
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Ruslan Ermilov wrote:
> 
> On Mon, Jun 25, 2001 at 06:47:41PM -0400, Deepak Jain wrote:
> > sysctl -A |grep forward
> > net.inet.ip.forwarding: 1
> > net.inet.ip.fastforwarding: 0
> > machdep.forward_irq_enabled: 1
> > machdep.forward_signal_enabled: 1
> > machdep.forward_roundrobin_enabled: 1
> >
> > What does the fastforwarding option do that the normal forwarding option
> > doesn't?
> >
> See inet(4).

The description there isn't very forthcoming.  fastforwarding caches
the results of a route lookup for destination addresses that are not
on the local machine, and uses the cached route to short-circuit the
normal (relatively slow) route lookup process.  The packet flows 
directly from one layer2 input routine directly to the opposing 
layer2 output routine without traversing the IP layer.

-- 
            "Where am I, and what am I doing in this handbasket?"

Wes Peters                                                         Softweyr LLC
wes@softweyr.com                                           http://softweyr.com/

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