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Re: Implementing 802.3ad-2000 link aggregation under Linux

To: Donald Becker <becker@xxxxxxxxx>, Ben Greear <greearb@xxxxxxxxxxxxxxx>
Subject: Re: Implementing 802.3ad-2000 link aggregation under Linux
From: Nick Towers <ncet@xxxxxxxxxxxx>
Date: Fri, 25 Aug 2000 11:39:51 +0100
Cc: Andi Kleen <ak@xxxxxx>, netdev@xxxxxxxxxxx
Organization: Dept. of Computing, Imperial College, UK
References: <Pine.LNX.4.10.10008250014300.2339-100000@xxxxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
Donald Becker wrote:
> 
> On Thu, 24 Aug 2000, Ben Greear wrote:
> 
> > Subject: Re: Implementing 802.3ad-2000 link aggregation under Linux
> > Andi Kleen wrote:
> > > On Thu, Aug 24, 2000 at 07:43:29PM +0200, Nick Towers wrote:
> > > > I am looking at starting a project to implment 802.3ad ethernet link
> > > > aggregation under Linux. For those of you that have never heard of it
> > > I started work some time ago. It is basically an user space problem.
> >
> > How would it be user-space?  Doesn't it aggregate several physical
> > layers together into one interface?  That seems like a kernel
> > level thing to me....
> 
> 802.3ad is not just channel bonding (the kernel-level mechanism), it also
> including sending packets down each link to detect topology and verify that
> the connection continues to work.

My original thought is that the actual aggregating and frame collection
/
distribution is certainly a kernel issue, as with the current bonding
driver. As for the link detection and automatic aggregation of links,
this is possibly a user space daemon - the number of packets is limited
to an ethernet "slow protocol" of max 5 packets per second so as to
give minimal effect to links which do not provide aggregation. However,
the protocol assumes almost immediate response from links which do
implement aggregation. Ie. Handling of the frame types is certainly
a kernel based issue.

The whole automatic topology side of the protocol is quite complicated
and not supported in all switches - I would say it is certainly a
"version 2" feature.

Nick
-- 
Nick Towers : Systems developer, Dept. of Computing, Imperial College
n.towers@xxxxxxxxxxxx or mailto:ncet@xxxxxxxxxxxx for point and click
If you feel lucky visit my web site - http://www.doc.ic.ac.uk/~ncet/

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