1gbps laptop network card issues Realtek 8168b

[ranj]

Hi edugeekers

 

Got a very weird problem that myself or none of my colleagues can figure out!

 

We recently brought 20 laptops, exactly the same model with exact specs.

 

We have one particular laptop where we have had issues with it not being able to get a network connection through the onboard LAN. The network card built in is a Realtek RTL8168B/8111B Family PCI-E GBE NIC.

 

It doesnt connect at all and just says "LAN is not connected".

 

We sent it back to the manufacturer of laptop (Novatech) and they said there was nothing wrong with it and even phoned us to check. We said we tried various network ports and couldn't get it working.

 

To give you all a picture, the majority of our network is gigabit to the majority of network ports around school and there are a few which are still 100mb. We mainly use Netgear smart/layer2/layer3 gigabit switches and have a few DLink gigabit switches. We also have a few Smart managed 10/100mb switches with gigabit uplink ports.

 

After a bit of digging around what was interesting was we managed to get the laptop LAN to work when connected to a 10/100 switch but niether the Dlink or Netgear 1gbps switches would make a connection at all. All the other 19 laptops work fine though whatever switch they are connected to.

 

We thought it could be a driver issues so matched the driver with the other laptops, even updating the driver on this problem laptop but still hasn't worked.

 

I am convinced it must be a problem with the laptop. Has anyone else suffered this issue?

 

Has anyone got any ideas of what this could be? we are confused...

 

thanks

[m25man]

Start by reading this PDF...

 

Auto Negotiation can be affected by cabling, jack plugs, faceplates, switch types and drivers.

 

Remember that Gigabit require all four pairs "8 conductors" and therefore all of the old cabling with bad punchdowns and poorly crimped ends will either simply not work or create all sorts of connectivity problems.

 

Connect your laptop directly to a known working gigabit port with a high quality cable does it work?

 

Try disabling auto negotiation on both the laptop and switch port, lock them to 100 mbps is it happy now?

 

Welcome to the real world of the 802.3ab Auto-Negotiation standard.

[FN-GM]

Start by reading this PDF...

 

Auto Negotiation can be affected by cabling, jack plugs, faceplates, switch types and drivers.

 

Remember that Gigabit require all four pairs "8 conductors" and therefore all of the old cabling with bad punchdowns and poorly crimped ends will either simply not work or create all sorts of connectivity problems.

 

Connect your laptop directly to a known working gigabit port with a high quality cable does it work?

 

Try disabling auto negotiation on both the laptop and switch port, lock them to 100 mbps is it happy now?

 

Welcome to the real world of the 802.3ab Auto-Negotiation standard.

 

If the others work surely it wont be this?

 

Can you get the laptop into ghost? try downloading netboot disk and see if it works in there.

[Michael]

Have you visually inspected the ethernet port on the laptop in question? If they say it's ok their end, you should ask what make/model switch they're using. You could also try plugging the laptop directly into your switch too.

[m25man]

If the others work surely it wont be this?

 

"To give you all a picture, the majority of our network is gigabit to the majority of network ports around school"

 

RANJ does not give any specific details of his test environment, but with the majority of his ports offering Gigabit to the desktop he has a massive potential for duff connections.

 

The amount of times I have seen the telco pairs crossed or badly crimped, plug these into a 10/100 and they will work fine put them into a Gig port and watch them fail.

Corrupted files (especially Word and Excel), slow log-on's and poor network browsing are all typical side effects.

 

Just for good measure if they do manage to connect using NWAY and negotiate a workable link and speed the power save of the driver kicks in shuts the card down on idle and then has to re negotiate when it wakes up!

 

Even though the standard allows the ability to disable auto-negotiation on Fast Ethernet 802.3u and Gigabit Ethernet 802.3z (fiber) technologies, it is neither required nor recommended.

Do not disable auto-negotiation between switches or NICs unless absolutely required, as physical layer problems may go undetected and result in spanning tree loops.

Disabling auto-negotiation should only be used as a troubleshooting aid or temporary workaround until the auto-negotiation problem is resolved. The alternative to disabling auto-negotiation is contacting the vendor for a software or hardware upgrade for IEEE 802.3 compliant Ethernet auto-negotiation support.

Old policies from years past for locked-down forced auto-negotiation disabled should be discouraged today.

 

Most Auto-neg issues end up being cabling related issues so I am inclined to agree with Michael in that there is someting amiss with the laptops physical LAN port that when offered up to a Gig link it doesn't negotiate correctly.

Locking both ends to 100Mb should eliminate any of the other 4 connections from the equation.

[DAckroyd]

Geoff (or others)... I've got a problem where the I've changed over the bursars computer and the new one has a gigabit NIC, the old one only had 10/100, the network speed ran fine for the first couple of weeks but then suddenly went onto go slow - could bad cabling be an issue and if so If I make a patch lead and only connect 4 cables to force 10/100 would that help? If so what pins need connecting?

Thanks, Dave

[ranj]

Thanks for the solutions, Unfortuntly I am certain its not any of these as if I connect another laptop from the same range, with the same network cable, same port, same switch it will work.

 

So the problem must lie in the network card, problem is I know it works but only through 10/100 connections.

 

I have tried changing the auto negotition options through to automatic configured which is the default, 100 half duplex and full duplex, 1000 half and full duplex and still nothing.

 

Thanks

[Michael]

It could well be a motherboard/NIC problem then if you've tried everything else. I can't see how it could be anything else.

[PeterW]

Is it on the same BIOS version as the others?

[DAckroyd]

If it's a new laptop send it back and ask for a replacement or your money back and get a better make. We had a novatec laptop brand new out the box and had motherboard fault and were meant to get a new laptop in exchange but ended up with the same one but mobo changed. genrally if you have a laptop playing up from new then it's likely to forever be a problem - to help things move on remind them there are other options on where to buy from - shame that when you find really good suppliers then end up with the office exploding - still plenty of other places to buy

[ejsaunders]

Do you have an onsite tester for NIC/cables? I'd try checking one of the known working ones and then test the port on the faulty laptop and see if anything's crossed or whatever, and if you have a more expensive tester than just whats connected to what, run that on it and check it out.

 

Also, have you tried a X-patch cable (crossed), I had one Realtek card once that NEVER liked uncrossed pair cable, it only worked on crossed, and I took months to figure it out, and even RT couldn't tell me why it made any difference to the NIC. Worth a try to save you sending it back.

[ranj]

Just as update for everyone, Novatech took it back again and tried the tests we tryed and it came down to a faulty mobo on the laptop, so they going to sort it for us. Very odd how it worked on 100mb switches and no gigabit.

[Michael]

Well Gigabit uses all 4 pairs, whereas operating at 10/100 doesn't use all 4 pairs. It could be either the port not making proper contact or a problem with the chip on the motherboard. Glad you got the answer/solution you wanted, eventually