Re: slow ethernet

[Dan Heaver <Dan.Heaver@fdmgroup.com>]

Ive just finished a large government project and we had autoneg problems
with our cisco catalysts and out sun servers - the Cisco guys upgraded the
software on the switch and the problem disappeared...

Not sure if the problem was the switch or not but it did disappear after the
upgrade....

Other projects I've worked on autoneg has been great.

Dan


-----Original Message-----
From: Henning Brauer [mailto:lists-openbsd@bsws.de] 
Sent: 16 February 2004 16:11
To: Misc @OpenBSD
Subject: Re: slow ethernet

* Nick <nick@holland-consulting.net> [2004-02-16 16:34]:
> > yet, the "autoneg is problematic" myth keeps spreading, yet it is utter
> > bullshit.
> 
> No.
> Take an iMac 333MHz running OpenBSD.
> Plug it into an autonegotiating switch.
> It will pick up 100Mbps, Full Duplex.  Why? Because the HW thinks it
> is best.
> It will choke and cough painfully on the data, however -- sucking data
> at a few kB/s.  
> Bump it down to 10Mbps, and it works fine.
> 
> Why?  Because the bm(4) driver that runs the NIC on this iMac is
> imperfect and can't handle 100Mbps.  You can argue that
> autonegotiation worked fine, but the problem is, the system AS A WHOLE
> doesn't work, and that's what people think is important: does it WORK
> AS DESIRED.

wait wait wait.
this is not an autoneg problem _at all_.
this is a problem of apple fucking up the hardware (or sombody else the 
driver).
this is a) clearly an exception and b) clearly not an autoneg problem!
it will not get any better if you hard-set both sides to 100 MBit/s 
full duplex.

> The problem with extreme statements is they can be disproven with one
> counterexample.  (Henning will deny it was a counter example 8-).

yes, completely unrelated issue.
apple fucked up the NIC, so autoneg is broken? ehh, wait a second...

> cables and second-hand NICs.  HOWEVER, I can't believe that
> autonegotiation is the one flaw-free technology we have ever developed
> in the computer industry.

oh wait, that is not the point, and that was never said.

the myth spreading is that autoneg doesn't work, especially with cisco 
switches, and this is plain bullshit.
especially the frequent advice to turn off autoneg on ANY performance 
problem is plain bullshit.
that's like giving the advice to change the memory timings in the bios 
every time someone reports that his computer dropped to ddb (no matter 
why). that might help in rare cases, but usually it is damn wrong, and 
pplz following that advice make the situation WORSE instead of better.
same with the turn-autoneg-off advice.

-- 
http://2suck.net/hhwl.html - http://www.bsws.de/
Unix is very simple, but it takes a genius to understand the simplicity.
(Dennis Ritchie)


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