Date: Sun, 30 Dec 2001 12:38:59 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Josef Karthauser <joe@tao.org.uk> Cc: Alexander Haderer <alexander.haderer@charite.de>, freebsd-hackers@FreeBSD.ORG Subject: Re: FreeBSD performing worse than Linux? Message-ID: <200112302038.fBUKcxx16943@apollo.backplane.com> References: <5.1.0.14.1.20011130181236.00a80160@postamt1.charite.de> <200111302047.fAUKlT811090@apollo.backplane.com> <20011130231802.E99520@tao.org.uk> <200111302345.fAUNjLI27798@apollo.backplane.com> <20011228153330.A11251@tao.org.uk> <200112300644.fBU6iVG10959@apollo.backplane.com> <20011230182612.D5642@tao.org.uk> <200112301917.fBUJHdm13120@apollo.backplane.com> <20011230191921.H5642@tao.org.uk> <200112301932.fBUJWYb13201@apollo.backplane.com> <20011230200707.A7332@tao.org.uk>
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:>=20
:> I use cheap 8 and 16-port netgear switches mostly. But even a little
:> 5-port switch may work for you, at least to start, to split your one
:> logical segment into five.
:
:There's not a lot of traffic on this side of the network, so hubs aren't
:too bad.
:
:Ok, this is the topology:
:
:
:laptop ---- [upstairs 10base hub]-----[Downstairs 10base hub] -----|
: |
: DSL ~~~~~~[Alcatel Router] ----- [FXP server FXP] -----|
:
:I get the same problem if I plug the laptop directly into the downstairs
:hub, and also if I plug it into the router (which has four hub ports on
:it). The server is configured as an ethernet bridging firewall.
:
:I think that it is extremely unlikely that the network infrastructure is
:failing in the same way when I plug into three different parts of it.
:Also, I didn't used to have this problem even with the came cabling.
:
:Joe
:...
Well, the amount of traffic isn't the problem. You have three hubs,
one of them being the Alcatel. Hmm. It's within what you are allowed
to do with HUBs but I don't trust it. I would either replace the
downstairs hub with a switch, or I would do this:
[upstairs]-----[downstairs-small-switch]
| |
| |
down alcatel
stairs router...
hub
|
(other stuff)
It would also be a good idea to test the laptop more directly,
by connecting the FXP server to a switch and then connecting the
laptop directly to the same switch.
The problem with HUBs is collision detection latency, but even a
collision occuring locally (i.e. between two downstairs machines)
can screw up the whole net if the hub configuration goes out of spec.
Collision detection problems often rear their ugly heads with small
packets, because the ethernet controllers don't even get 'late collision'
errors.
-Matt
Matthew Dillon
<dillon@backplane.com>
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