Network Slowdowns?

Oliver Fromme check+j78jxb00rsfr0v4i at fromme.com
Mon Oct 16 09:08:40 PDT 2006


Jamie wrote:
 > [Duplex settings]
 > Well.. I don't know if I should be too thankful.. was hoping they'd be 
 > set differently.

They _are_ set differently.

 > DragonflyBSD:
 > xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
 >        media: Ethernet 100baseTX <full-duplex>

So, that means that auto-negotiation is switched _off_ on
that NIC, and the media has been manually set to 100baseTX
with full-duplex.

 > It doesn't say the speed, but can I assume 100baseTX means it's 100Mb/s ?

yes, that's right.

 > Linux:
 > Settings for eth0:
 >        Speed: 100Mb/s
 >        Duplex: Full
 >        Auto-negotiation: on

And that means that auto-negotiation is _on_, and the media
was set to 100baseTX full-duplex.

You should either enable auto-negotiation on both sides,
or disable it on both sides.  It does _not_ work reliably
when only one side tries to do auto-negotiation.

To enable it on FreeBSD:  ifconfig xl0 media autoselect

Of course, whether that fixes the network slowdowns that
you're experiencing is a different question.  Nevertheless
you should configure the auto-negotiation correctly, just
to eliminate a potential source of problems.

BTW, I assume that the two machines are directly connected
with a cross-over cable.  If there is _anything_ between
(e.g. a switch), then the situation is different, of course.

Best regards
   Oliver

-- 
Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd

Any opinions expressed in this message may be personal to the author
and may not necessarily reflect the opinions of secnetix in any way.





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