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Date:      Wed, 26 Dec 2001 18:31:34 -0800
From:      "Philip J. Koenig" <pjklist@ekahuna.com>
To:        stable@FreeBSD.ORG
Subject:   Re: 4.5 PRERELEASE - Call for testing
Message-ID:  <3C2A1786.17075.63462D@localhost>
In-Reply-To: <bulk.9350.20011226123801@hub.freebsd.org>

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On 26 Dec 2001, at 12:38, stable-digest boldly uttered: 

> Date: Wed, 26 Dec 2001 14:00:27 +0100
> From: sthaug@nethelp.no
> Subject: Re: 4.5 PRERELEASE - Call for testing
> 
> > > Thus the advice to either use auto-negotiate everywhere, or use manual
> > > everywhere. One end auto-negotiate and one end manual is a recipe for
> > > disaster.
> > 
> > So, that implies that in these cases non-managable switches are doomed
> > as you cannot 'hard-set' them to some value.
> 
> If auto-negotiate fails on non-managable switches, you can usually get
> it to work after the fact by manually configuring the box at the other
> end.
> 
> Steinar Haug, Nethelp consulting, sthaug@nethelp.no


Actually that is not always the case.  I have a Netgear "auto-
sensing" 8-port switch here which, no matter what I do, won't run 
half-duplex with an Intel 82558-based card, even if the Intel is 
"locked" at half-duplex.  I'm told in this particular case that it 
has to do with Intel's (Windoze) NIC drivers, who knows.  Others in 
this thread said you need to have both sides manual or both sides 
auto.

I have also seen situations where an HP Procurve switch would not run 
correctly at 10Mbps/Half with a 3com 3CXFE575BT PC-card NIC, even if 
BOTH sides were "locked" at that speed.  The symptom was very slow 
communication HP --> 3com, the other direction was OK.  At 100Mbps it 
was fine. (this was also under windoze)

There are no shortage of scenarios where auto-negotiation does NOT do 
what you want, even if just one end is "locked".  And sometimes there 
are even issues when everything is set manually.  See below.


> Date: Wed, 26 Dec 2001 11:43:29 -0800 (PST)
> From: Tom <tom@uniserve.com>
>
>  I would recommend people use auto everwhere.  Even the cheap devices
> support it properly now. Auto-negotiation is going to become more
> critical as more options are added to the ethernet standard (ie. 
> master/slave, flow control).


The problem with this is that we DON'T always want every link to 
operate at its "maximum" setting.  

I have little interest in giving huge chunks of bandwidth to every 
miscellaneous user (and along with it the ability to do something 
dumb like bog the whole network down when they accidentally drag 
their entire hard drive icon to a network drive) when their work 
amounts to saving a couple of word processing documents to a server 
each day.  Those people don't even need 10Mbps of bandwidth, much 
less 100 or more.

All switches should have configurable ports, IMHO.


Phil



--
Philip J. Koenig                                       pjklist@ekahuna.com
Electric Kahuna Systems -- Computers & Communications for the New Millenium


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