Odd networking problem

[Psycho Smiley]

Hi all. I'm having intermittent issues with my connection, and was wondering if anyone could point me in the right direction.

I'm running WinXP Pro. When I'm on the university LAN, occasionally the computer will lose the connection, and report that the cable has been disconnected. The indicator LEDs go out, the whole bit. The problem is, the cable is still in, and the LAN admins say the connection is fine at the switches.

No matter what I do with the computer (restart, uninstall/reinstall network card, disable/enable connection, switch cables, etc) I can't pick the connection back up. If, however, I shutdown, go to another LAN drop, and power back up, I can connect there. If I then go back to my LAN drop, the connection picks back up and carries on until the next time.

I've tried changing power management settings, updated the drivers for the card, updated Windows, etc, with no apparent effect.

The drop-outs can happen whether I'm actively using the connection or not, and even when the computer is in standby with the card powered down. The event viewer notes the drop as:

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The system detected that network adapter \DEVICE\TCPIP_{F23AA529-3D24-4EE3-A715-55CB60CE3F2B} was disconnected from the network, and the adapter's network configuration has been released. If the network adapter was not disconnected, this may indicate that it has malfunctioned. Please contact your vendor for updated drivers.

One other event usually seems to happen just before that:

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The browser has forced an election on network \Device\NetBT_Tcpip_{F23AA529-3D24-4EE3-A715-55CB60CE3F2B} because a master browser was stopped.

Any ideas?

[Xisiqomelir]

Try burning a copy of one of the live-on-CD linuxes, like Knoppix or Ubuntu. See if they also experience disconnect. If they do it might be the network hardware.

[Psycho Smiley]

Arg, sorry, forgot to mention I'd done that. The problem behaved the same way in Puppy Linux as in WinXP. It worked if I switched network drops, and not if I didn't. So I think it's either a hardware problem on my end (would that remain after a cold restart?) or a hardware problem on the LAN end.

[TheFeniX]

It could be your network drop.

Try setting your NIC to 10Mb/s half-duplex and test that. You can run 10 meg on just about anything, so it should rule out the cable.

At higher speeds cross-talk becomes more of an issue. If they punched the drop down incorrectly, that could explain it.

[TrailerParkJawa]

By eliminating the OS, the driver, the cable from your PC to the drop you are left with the NIC itself, the drop itself or the cable between the drop and the switch. This leaves the NIC itself or the network connection from the drop to the switch. Assuming there isnt a problem with the port on the switch your drop is plugged into then I'd tend to believe you might have a network card problem.

Do you have a buddy that can bring over a laptop and see if they ever lose connection? If they do then you can safely assume its not your problem and something the university needs to address.

[Psycho Smiley]

Try setting your NIC to 10Mb/s half-duplex and test that. You can run 10 meg on just about anything, so it should rule out the cable.

Now, that was interesting. I had it on Auto-Detect before. I dropped it to 10Mb/s half-duplex, and that TRIGGERED the drop. Without disconnecting, I bumped it up to 100BaseTX (no half-duplex) and it immediately picked up, connected to the DHCP server, registered, and went fully operational. I think I'll run like this for a while and see what happens. Perhaps the auto-detect mode was fucking up somehow? If not, I may now have a way to force a reconnect.

As for the second computer idea, the error can happen every couple of hours or every couple of weeks. I don't think I can borrow a second machine long enough to rule anything out.

[TrailerParkJawa]

Now, that was interesting. I had it on Auto-Detect before. I dropped it to 10Mb/s half-duplex, and that TRIGGERED the drop. Without disconnecting, I bumped it up to 100BaseTX (no half-duplex) and it immediately picked up, connected to the DHCP server, registered, and went fully operational. I think I'll run like this for a while and see what happens. Perhaps the auto-detect mode was fucking up somehow? If not, I may now have a way to force a reconnect.

I wonder why a reboot didnt have the same effect to trigger a reconnect unless something in the speed negotiation process if failing? Do you know the switch at the other end is hard set for 100/FULL or Auto-negotiate? At least now you might have a work around.

As for the second computer idea, the error can happen every couple of hours or every couple of weeks. I don't think I can borrow a second machine long enough to rule anything out.

Intermittent problems are the worst! Good hunting.

[Psycho Smiley]

No idea what the switch is configured like. The helldesk just asks "is it working NOW?" and if I say yes, they close the ticket. If I say no, they call back the next day. Repeat until ticket is closed.

[Psycho Smiley]

Update: This morning, it crapped out at 100Mb/s, and dropping to 10/FULL picked it back up. Going back to 100 (half and full) re-dropped it, so it's sitting at 10 right now.

So does this sound like a hardware problem with my NIC, with the network, or still not enough info?

[TheFeniX]

Update: This morning, it crapped out at 100Mb/s, and dropping to 10/FULL picked it back up. Going back to 100 (half and full) re-dropped it, so it's sitting at 10 right now.

So does this sound like a hardware problem with my NIC, with the network, or still not enough info?

It COULD be a problem with your NIC, but you said you tried it on another drop and it worked fine. So here's the deal:

if on another network plug it looses your connection, then it's your NIC. But you said this wasn't the issue.

if it doesn't, and you you have no outages with 10 Mb/s half-duplex, then I'd have to assume your drop is incorrectly punched down. They may have a loose wire, or the jack may be damaged. Call your IT group and ask them to test the drop, preferably with something more than a wiremap tester. You can have a good wiremap but still have a network drop that won't pass cross-talk or db loss tests.

If you're gung-ho about it, you can take the faceplate off the wall and examine the drop yourself. Look for bent pins in the jack or other debris blocking a good connection. Then examine the back and make sure all the wires are where they should be (they should punch B style, but some places use A, it's labeled on the jack, or should be), and that they are all the way down.

I'd advise against this though as many IT groups get pissed when you start playing around with their stuff.