Broadcom cards continually re-negotiating, showing short?

  • Thread starter Thread starter Mike
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Mike

I have a network with 13 HP DC5750 desktops. Almost all of them are
exhibiting a strange behaviour. They drop the network connection for a
few seconds, and then reconnect. In the event log, I see this event
repeatedly:

'Broadcom NetXtreme Gigabit Ethernet: Network controller configured
for 100Mb full-duplex link'

On some machines, it does not happen too often, once every week or so.
But on some, it is happening once an hour, and even once every few
minutes sometimes. Also, when I run the Broadcom Diags, and run cable
test, it shows that 2 of the 4 pairs have a short. At first, I
thought, AHA!, that's the problem. But now it seems suspicious,
because all my computers are showing 2 shorted pairs. While it is
possible, I doubt that they are all shorted.

Has anyone else seen this happen? I'm going to try new cables to make
sure, but beyond that, this seems pretty weird to me. Maybe it's the
cheapo Linksys switch they are plugged into? Or maybe there are
Gremlins chewing on my cables at night? Many of the events are
registering after midnight.... :)
 
I have a network with 13 HP DC5750 desktops. Almost all of them are
exhibiting a strange behaviour. They drop the network connection for a
few seconds, and then reconnect. In the event log, I see this event
repeatedly:

'Broadcom NetXtreme Gigabit Ethernet: Network controller configured
for 100Mb full-duplex link'

On some machines, it does not happen too often, once every week or so.
But on some, it is happening once an hour, and even once every few
minutes sometimes. Also, when I run the Broadcom Diags, and run cable
test, it shows that 2 of the 4 pairs have a short. At first, I
thought, AHA!, that's the problem. But now it seems suspicious,
because all my computers are showing 2 shorted pairs. While it is
possible, I doubt that they are all shorted.

Has anyone else seen this happen? I'm going to try new cables to make
sure, but beyond that, this seems pretty weird to me. Maybe it's the
cheapo Linksys switch they are plugged into? Or maybe there are
Gremlins chewing on my cables at night? Many of the events are
registering after midnight.... :)
Click to expand...

Have you considered checking for updated drivers?

Also, are these cables passed through walls / ceilings ?
 
Have you considered checking for updated drivers?

Also, are these cables passed through walls / ceilings ?- Hide quoted text -

- Show quoted text -
Click to expand...

Yep, the NIC drivers (as well as bios and all other drivers on the
systems) are up to date.

I went on-site on Sunday to work on this problem, and I found that the
systems going into Standby every night seems to be related. I disabled
Standby on all the systems, rebooted them, and now NONE of them are
having any issue. I'm hoping there is a way to still use Standby but
not cause NIC issues.
 
Mike said:
I have a network with 13 HP DC5750 desktops. Almost all of them are
exhibiting a strange behaviour. They drop the network connection for a
few seconds, and then reconnect. In the event log, I see this event
repeatedly:

Has anyone else seen this happen?
Click to expand...

Yes. On every computer with these LAN chips. Plus a few other makes.

http://mylogon.net/support/psave
 
:

Also, when I run the Broadcom Diags, and run cable
test, it shows that 2 of the 4 pairs have a short. At first, I
thought, AHA!, that's the problem. But now it seems suspicious,
because all my computers are showing 2 shorted pairs. While it is
possible, I doubt that they are all shorted.
Click to expand...

10/100 Ethernet uses the red and green pairs only, and a signal transformer
is connected across each pair. Thus a healthy connection shows:

No connection (infinite resistance) between any two pairs.
Low resistance across the two wires of the red or green pair.
No connection between the wires of blue or brown pairs.

On 1000MHz cables, all four pairs are used.

A common mistake in Ethernet wiring is to use a nonstandard wiring-order
such that transmit and receive signals are split across pairs. When you
understand that the twisted pairs are there to segregate the signals, it will
be obvious that this will give rise to all sorts of intermittent troubles
through crosstalk. Thus, unlike most other electrical installs, you MUST
follow the official wiring scheme or it won't work.

Just thought I'd mention this as it's another frequent cause of LAN troubles.

Looking at the side of the plug without the clip:
White/Orange
Orange/White
White/Green
Blue/White
White/Blue
Green/White
White/Brown
Brown/While

-and yeah this may look totally wacko but it's right!
 
:

 Also, when I run the Broadcom Diags, and run cable


10/100 Ethernet uses the red and green pairs only, and a signal transformer
is connected across each pair. Thus a healthy connection shows:

No connection (infinite resistance) between any two pairs.
Low resistance across the two wires of the red or green pair.
No connection between the wires of blue or brown pairs.

On 1000MHz cables, all four pairs are used.

A common mistake in Ethernet wiring is to use a nonstandard wiring-order
such that transmit and receive signals are split across pairs. When you
understand that the twisted pairs are there to segregate the signals, it will
be obvious that  this will give rise to all sorts of intermittent troubles
through crosstalk. Thus, unlike most other electrical installs, you MUST
follow the official wiring scheme or it won't work.  

Just thought I'd mention this as it's another frequent cause of LAN troubles.

Looking at the side of the plug without the clip:
White/Orange
Orange/White
White/Green
Blue/White
White/Blue
Green/White
White/Brown
Brown/While

-and yeah this may look totally wacko but it's right!
Click to expand...

Oh yes, trust me the cable pairs are in the correct color order. I
made that mistake a long time ago and had to re-do a lot of cables so
I always check that. After that happened, I've been known to recite
the color order in my sleep!
 
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