[c-nsp] Speed Issues

Ted Mittelstaedt tedm at toybox.placo.com
Fri Feb 3 06:13:34 EST 2006

>-----Original Message-----
>From: cisco-nsp-bounces at puck.nether.net
>[mailto:cisco-nsp-bounces at puck.nether.net]On Behalf Of Justin
>M. Streiner
>Sent: Thursday, February 02, 2006 10:52 AM
>To: cisco-nsp at puck.nether.net
>Subject: Re: [c-nsp] Speed Issues
>> Configure *both* sides to AUTO and all should be well.
>Or configure the NIC in the server to run at 100/full.  It's been my
>experience that speed/duplex autonegotiation doesn't always produce the
>best results.

And it's been my experience that the undesirable results during
autonegotiation only happen when the cabling is substandard, or
some other thing like that.

You have to start by setting both sides to auto, and check the nic driver
and switch also to make sure the flow control settings match, since
some of the chipsets don't properly handle that negotiation.  If that
fixes it then leave it alone.  Otherwise hard code both sides and see
what happens.  But, before doing any of that, check the cabling.

I just solved one of those problems today - the people that installed
the server used some home-built ethernet cable on a gigabit port -
I looked closely at that cable and discovered they had used crimp
plugs designed for stranded cable, and the cable itself was solid
core.  A lot of people out there who think they know how to crimp
up an ethernet cable, actually don't.  And there's unfortunately also
some people out there who think they know how to cable a patch
panel, who shouldn't come within 20 feet of a punchdown tool.


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