Network connection only stable @ 10mbit.

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Have an interesting issue with one of my LAN connections. No matter
what machine we hook up to it, and no matter what speeds the LAN card
is capable of or how it is configured, we can only get a stable network
connection when it is plugged into a 10mbit hub (and the workstation
normally there is capable of Gigabit speeds).

The wiring in the walls between this users office and the server room
is Cat5 UTP and we've used our (new to us, so we're still somewhat
getting used to it) AEMC Wire Mapper Pro to verify that the wiring and
patch cables at each end test out OK.

Does anyone have any clue how I can test further. Is it possible that
our Wire Mapper might be fibbing to us? This is the Presidents office,
so I need to come up with something better than shrugging my shoulders.
TIA!



Re: Network connection only stable @ 10mbit.
mwalsh@smad.com wrote:
> Have an interesting issue with one of my LAN connections. No matter
> what machine we hook up to it, and no matter what speeds the LAN card
> is capable of or how it is configured, we can only get a stable network
> connection when it is plugged into a 10mbit hub (and the workstation
> normally there is capable of Gigabit speeds).

Did you check duplex setttings??

If thats ok, Id repull a new cable.  What category of copper is that
computer connnecting to?

Joe Perkowski




>
> The wiring in the walls between this users office and the server room
> is Cat5 UTP and we've used our (new to us, so we're still somewhat
> getting used to it) AEMC Wire Mapper Pro to verify that the wiring and
> patch cables at each end test out OK.
>
> Does anyone have any clue how I can test further. Is it possible that
> our Wire Mapper might be fibbing to us? This is the Presidents office,
> so I need to come up with something better than shrugging my shoulders.
> TIA!
>



Re: Network connection only stable @ 10mbit.
mwalsh@smad.com wrote:
> The wiring in the walls between this users office and the server
> room is Cat5 UTP and we've used our (new to us, so we're still
> somewhat getting used to it) AEMC Wire Mapper Pro to verify
> that the wiring and patch cables at each end test out OK.

I'm not familiar with the AEMC but this sure sounds like a
case of a split pair.  What jacks are you using at each end?
Which color code, T-568A or -B?  Who made the patch-cords?
You could swap them out for known-good.

-- Robert



Re: Network connection only stable @ 10mbit.
Robert Redelmeier wrote:
> mwalsh@smad.com wrote:
>
>>The wiring in the walls between this users office and the server
>>room is Cat5 UTP and we've used our (new to us, so we're still
>>somewhat getting used to it) AEMC Wire Mapper Pro to verify
>>that the wiring and patch cables at each end test out OK.
>
>
> I'm not familiar with the AEMC but this sure sounds like a
> case of a split pair.  What jacks are you using at each end?
> Which color code, T-568A or -B?  Who made the patch-cords?
> You could swap them out for known-good.
>
> -- Robert
>
I would agree with Robert, it could be something like a split pair.  When
using a tester that tells where it is in the negotiating a link proccess,
split pairs will usually fail and auto-negotiate, or will show a link
light, but not actually get a connetion (as in not getting an IP when using
DHCP).  Also, if its Cat5, you could have some low end connectors/cable
along with bad install which would cause this as well.  Can you make out a
brand on the connectors/patch panel and cable?  How does the termination
look?  Is the jacket stripped way back, or is it close to the jack?


Re: Network connection only stable @ 10mbit.
mwalsh@smad.com wrote:

> Have an interesting issue with one of my LAN connections. No matter
> what machine we hook up to it, and no matter what speeds the LAN card
> is capable of or how it is configured, we can only get a stable network
> connection when it is plugged into a 10mbit hub (and the workstation
> normally there is capable of Gigabit speeds).
>

You've likely got a bad connection or misswired cable.



Re: Network connection only stable @ 10mbit.

> Have an interesting issue with one of my LAN connections. No matter
> what machine we hook up to it, and no matter what speeds the LAN card
> is capable of or how it is configured, we can only get a stable
network
> connection when it is plugged into a 10mbit hub (and the workstation
> normally there is capable of Gigabit speeds).
>
> The wiring in the walls between this users office and the server room
> is Cat5 UTP and we've used our (new to us, so we're still somewhat
> getting used to it) AEMC Wire Mapper Pro to verify that the wiring and
> patch cables at each end test out OK.
>
> Does anyone have any clue how I can test further. Is it possible that
> our Wire Mapper might be fibbing to us? This is the Presidents office,
> so I need to come up with something better than shrugging my
shoulders.
> TIA!

If your tester cannot test for split pairs (and many cannot), then your
tester is not telling you the whole story.  If you test it with the
right tester, you will likely find that there is a split pair.  Or just
cut both ends off and repunch them down again, and then see what
happens.

But of course, if you repunch them incorrectly, then you will still have
the sam problem.




Re: Network connection only stable @ 10mbit.
According to the manufacturer's web site, the tester in question does
test for split pairs.  There's probably a minimum cable length required
for split pair detection, but that should only be an issue when testing
patch cables, because the minimums are so short.



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