From owner-freebsd-questions  Wed Apr 22 17:48:42 1998
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Date: Wed, 22 Apr 1998 17:48:22 -0700 (PDT)
From: Doug White <dwhite@gdi.uoregon.edu>
Reply-To: Doug White <dwhite@resnet.uoregon.edu>
To: Mike D Tancsa <mdtancsa@sentex.net>
cc: questions@FreeBSD.ORG
Subject: Re: How to reset an fxp ethernet interface
In-Reply-To: <199804221920.PAA29587@granite.sentex.net>
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On Wed, 22 Apr 1998, Mike D Tancsa wrote:

> I came across something I dont quite understand and not sure where to start
> looking. I am in the process of adding a new FreeBSD box into the
> production mix and was testing out the interfaces and cabling for it when I
> discovered this behaviour that I am not sure if is switch related or driver
> related.
> 
> machine A and B connected via a switching hub, both media: 100baseTX
> <full-duplex>
> 
> transfer a file from B to A
> 49643600 bytes received in 15.58 seconds (3.04 MB/s)
> 
> Looks good.
> 
> Now, I want to test a different cable, to make sure the big file transfers
> OK, without generating input or output errors on either side of the
> interface. So I unplug the existing cable and plug in the new cable.
> 
> 49643600 bytes received in 52.35 seconds (926.02 KB/s)

Thoughts:

1.  The cable makes all the difference in 100mbit.  Crappy cable gets you
crappy performance.  Also, bad cabling can trick the hub into downing you
to 10mbit (where 926k/s would be a great xfer rate).  

2.  Try forcing the port speed in the hub.  Autodetection is still pretty
new and isn't fully reliable.

Doug White                              | University of Oregon  
Internet:  dwhite@resnet.uoregon.edu    | Residence Networking Assistant
http://gladstone.uoregon.edu/~dwhite    | Computer Science Major



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