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Date: Sat, 17 Apr 2004 13:23:50 -0400 (EDT)
From: Robert Watson <rwatson@freebsd.org>
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To: Lowell Gilbert <freebsd-current-local@be-well.no-ip.com>
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cc: Julian Elischer <julian@elischer.org>
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Subject: Re: RFC: ported NetBSD if_bridge
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On 17 Apr 2004, Lowell Gilbert wrote:

> Julian Elischer <julian@elischer.org> writes:
> 
> > On Fri, 16 Apr 2004, Bruce A. Mah wrote:
> 
> > > 1.  ng_bridge(4) doesn't do spanning tree.  Neither does bridge(4).
> > 
> > WHICH spanning tree? Spanning tree is a generic term..
> > Are you refering to a particular implimentation of something that uses
> > spanning tree algorythms?
> 
> They're referring to IEEE 802.1d.  This is an important feature for
> building large bridged networks. 

And it's an important part of many ethernet-layer redundancy solutions,
since it allows fail-over when one bridging element or graph edge goes
offline.  It's something we really missed in some research work I was
working on to build link layer filters, since it was an easy way to
provide basic fail-over in the presence of ethernet link failures (and
they happen a lot!)

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert@fledge.watson.org      Senior Research Scientist, McAfee Research