100Mbps network only runs at 10Mbps - long!

Got a really wierd problem here.

Recently upgraded our network - got a 100Mbps switch. Really cool. All NICs support this higher speed, so we thought it wuld be excellent.

But here's the catch. None of our rooms can run at 100 - we can only run at 10. Seems simple enough (maybe) but read on....

There is a port in the lounge that can run successfully at 100. We made sure patch cables are configured same way - no joy. So we disconnected network ports and plugged it straight into PC. (In effect, this makes a really long patch from PC to switch which is configured same as one that works). No joy.

Tried different port on the switch. No joy.

Tried a laptop (that works in lounge) and brought it in here. Now it can't run at 100Mbps connection. Did the thing with the cable - effectively the same (but longer) patch cable directly from known working laptop direct to switch. Only 10.

It's wierd but we seem to have narrowed it down to fact that something related to either lengh of network cables, or maybe they are too close to power cables...?

Using Cat5 (blue) cable, and a NetGear switch. All laptops/PCs are using Intel NICs. But like i said, seems to be a problem with the wires themselves?!

So then - cables are not *that* long. Maybe 10 metres at most. (er... 35 ish feet?) Only thing we can think of is closeness to power cables or something.

Any way to shield these cables? Any way to test whether or not it is something to do with proximity to power cables?

Got all this lovely kit and it is prety much useless unless we all set up our PCs in the lounge!!!

First thing to check - are the NIC's enabled to use 100 Megabit? You can check this by going to Control Panel > Network > Select the NIC > Properties

Second thing to check - connect one of the problem computers to the switch using a short cable. We have a bunch of patch cables that are only three feet long. If you suspect interference, this should eliminate that part of the equation. The maximum length for CAT5 is 300 feet, so you're not anywhere close to the limit.

MacGyver - cheers for the tip, dude.

We already tried changing NIC properties... When we switch to 100 packets get sent (netbios broadcast I guess) but nothing comes back. We send only - not receive. This is same either on full or half duplex.

OK - so I set up my PC in the lounge, which uses a shorter patch cable and is going firectly to switch with no power cables anywhere in sight. This *works*!! Dammit. Must be interference, then. Will have to look at where the cables actually go, which will involve pulling up carpets again. Ar5e.

Another thing to add to the equation - you remember how I said almost all PCs are capable of 100Mbps...? Well our linux box doesn't - it must have the cheapest NIC ever - it can only run at 10 half duplex. And our cable router only runs at 10 too, apparently. Not sure if this is important - I think the switch is supposed to be intelligent enough to cope with that. Plus the fact that when in lounge (with both linuxbox and router on the network) it works fine.

Guess it's gotta be interference.

Anyone know any good information on interference: what causes it, how to avoid it, how to minimize it etc...?

Cheers,

Dan.

For interference, look for fluorescent tubes, strong electrical appliances or motors (ie: heating or cooling systems), microwave ovens, and the like.

</font><blockquote><font size="1" face="Trebuchet MS, Verdana, Arial, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Trebuchet MS, Verdana, Arial, Helvetica, sans-serif">Originally posted by gutted:
<strong>
And our cable router only runs at 10 too, apparently.

</strong></font><hr /></blockquote><font size="2" face="Trebuchet MS, Verdana, Arial, Helvetica, sans-serif">I'm gonna go with interferance as well. But as far as your router only getting a 10mb connection that is normal. I think the fastes cable out there (uncapped and all that) is only like 6 or 8mb so there is no reason to have a 100mb adapter in the modem/router. Just my 0.02

what kind of cables r u using?

if your not using precrimped cables then youll have problems with the connectors. or if u arent using a patch panel then i would suggest getting one and get patch cable and get the connectors that r used for patch panels. dont know what they r called. but i had this prob at two sites i work for.

We're not using pre-crimped cables - we've made the cables up to correct length and crimped them ourselves. We know for sure that the original cables (the "infrastructure" if you like) in our rooms is all ok as we had a tester thing to be sure our crimping was ok. We've got boxes (network points? patch panels? I'm not sure) in each of our rooms. Then we use standard (pre-crimped) patch cables to connect from NIC to network point.

The other cable in the lounge (the one that actually works) has got RJ45s on both ends (no box) but that was made after we had given the tester back. Based on this, it looks like our crimping is ok - although worth double checking based on your experience.

I think we've already covered your test (if these network boxes are the same as the patch panels you describe) but I'll try and get hold of another tester to double check - cheers for the tip, dude.

I would double check, and then have a friend double check the wallplates/"Network Points".
They are EXTREMELY EASY to get backwards.

Speaking from experience...

One other thought. If the switch is manageable, make sure each port is set to "auto"

Sounds like you have the wrong wiring scheme. I have the same problem here where I work because the guy who was here before me wired most of the jacks wrong.

In order for 100Mps ethernet to work properly over long distances, you have to follow a specific wiring code so that the twisted pairs stay together. Since ethernet sends and receives over pairs 1,2 and 3,6, you have to make sure that the wires crimped to those terminals stay twisted together in the cabling. Because of this, you can't just use a straight-across wiring scheme. A cheap tester will say everything is OK because it doesn't check to see where the pairs are.

The color code I use is this:

Orange/white
Orange
Green/white
Blue
Blue/white
Green
Brown/white
Brown

Try making a really long patch cable with both ends like this and plug one end into your switch and the other into one of the systems that will only run at 10 Mbps. Let us know if it jumps up to 100 Mbps. If it does, then the wiring in the walls is flawed.

Interference shouldn't really be an issue on a short 35 foot run, unless you are using extremely cheap UTP, the cable is crimped, the wires are untwisted too far from the termination block, or the cables are passing by a nuclear power generator <img border="0" title="" alt="[Wink]" src="wink.gif" /> . Where I work we have quite a few -+300 ft. runs that pass numerous flourescent lights and power lines and still work fine. Just make sure you don't crimp the cable and that both ends are terminated using the RJ45-568B standard (see below) and you should have no problem.

OW O GW B BW G BrW Br

Should be able to get a switch that will run 10/100