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Can't operate LAN at 100mbps

T

TheMafioso

Member
Hi Guys,

I have 3 computer connected in LAN through switch (which is rated to operate at speeds upto 200mbps).All the LAN cards on my computers are capable of operating at 100 mbps.I have WindowsXP SP2 installed on all my three systems.

The problem is i still can't operate the LAN at speed of 100 mbps.The connection between the computers and switch takes place and i'm notified that computer is connected at 100 mbps but i can't transfer any data between them.
When i set the speed to 10mbps in Network Adapter's Properties, the LAN works flawlessly.
So tell me what could be the problem, why can't my LAN work at 100mbps.

Regards
 
well if by changing the speed things are working properly for you then that takes out the OS and any protocol. We're probably dealing with a layer 1 problem here.

That means the cabling.

1st, make sure all network cards are set to auto detect speed/duplex. Second, describe they physical wiring of this network. Most times when folks make their own network cables it results in a "net-no-working"
 
case 1:
My brother in law has a Dell Precision workstation (don't remember the model). The onboard 3Com NIC wouldn't work in 100Mb or auto-sense; it would only operate in 10Mbps mode.
Using the same cable, a different NIC that I threw in works in any mode (100/10/auto).

case 2:
A brand new HP box at work dual boots between WinXP and Linux. In my cube the NIC only works under WinXP, and not Linux (same NIC, cable, and everything). When I move the box to a different cube, NIC works fine under both OS.
We thought something was wrong w/ the onboard NIC and had HP to come over and replace the motherboard - same result.

Sometimes there are things that you just can't explain logically...so even if all your wiring is correct, and it still doesn't work right, don't waste too much time on this.
 
Originally posted by: Cooky
case 1:
My brother in law has a Dell Precision workstation (don't remember the model). The onboard 3Com NIC wouldn't work in 100Mb or auto-sense; it would only operate in 10Mbps mode.
Using the same cable, a different NIC that I threw in works in any mode (100/10/auto).

case 2:
A brand new HP box at work dual boots between WinXP and Linux. In my cube the NIC only works under WinXP, and not Linux (same NIC, cable, and everything). When I move the box to a different cube, NIC works fine under both OS.
We thought something was wrong w/ the onboard NIC and had HP to come over and replace the motherboard - same result.

Sometimes there are things that you just can't explain logically...so even if all your wiring is correct, and it still doesn't work right, don't waste too much time on this.
Click to expand...

In all honesty that really sounds like a cabling problem...most likely a split pair or reversed polarity.
 
What's reversed polarity?
So I may have made some mistakes when I did the wiring, but how does that explain the same cable and NIC works in WinXP, but not in Linux?
 
Originally posted by: Cooky
What's reversed polarity?
So I may have made some mistakes when I did the wiring, but how does that explain the same cable and NIC works in WinXP, but not in Linux?
Click to expand...

different drivers handle reversed polarity differently...some are OK with it and will internally switch, others not.

reversed polarity is having the tip and ring wires reversed on the same pair.
 
Originally posted by: spidey07
well if by changing the speed things are working properly for you then that takes out the OS and any protocol. We're probably dealing with a layer 1 problem here.

That means the cabling.

1st, make sure all network cards are set to auto detect speed/duplex. Second, describe they physical wiring of this network. Most times when folks make their own network cables it results in a "net-no-working"
Click to expand...

Auto detect speed/duplex sets the cards to operate at 100mbps, and as i've said before, i'm notified that i'm connected at 100mbps but no data transfer takes place.
Well all the cabling is done by me.I'm using the standard CAT5 cable, using RJ-45 jacks in straight-thru mode which is like this:
http://img414.imageshack.us/img414/4392/image22lr.jpg

And Guys i'm pretty sure that nics can operate at 100mbps 'cause when i connect the computers using cross-over cable, i get full 100mbps.
 
its the cabling.

almost guaranteed, especially if it is homemade cable (rarely does well)

try it with storebought cable

-edit- common misconception is if you get a link light that means the cable is good or that the card will test the cable. Getting a link light just means you received some voltage on the receive portion of the network card. So it is very, very, very common to have "bad cabling" and still get a link light.

When switches/cards autonegotiate they do no testing. Just shout out (in their link pusle) "Hey! I can do 100 full!" So there isn't any acknowledgement or anything and communication on what the cards/ports select.
 
i have always wired - white orange, orange, white green, blue, white blue, green, white brown, and brown

as you can see the orange and green are opposite the way you wired, and those are your TX and RX lines

try recabling one, and see if it helps.
the fact that a crossover cable works, tells me you definately have a cabling issue.
 
Originally posted by: petey117
i have always wired - white orange, orange, white green, blue, white blue, green, white brown, and brown

as you can see the orange and green are opposite the way you wired, and those are your TX and RX lines

try recabling one, and see if it helps.
the fact that a crossover cable works, tells me you definately have a cabling issue.
Click to expand...

Hey man, are u taking about this sorta arrangement ?
http://www.supload.com/thumbs/default/Image1-367167.jpg

If yes i wonder what sort of difference its gonna make, 'cause here also we are connecting the wires in one to one corrospondence, so it should be identical to this arrangement in which my cabling is done
http://img414.imageshack.us/img414/4392/image22lr.jpg

Am i missing out on something ?
 
i understand it looks like it wouldn't make a difference, but i figure it is worth a shot
what kind of switch are you plugging into?
 
Its a 8 port switch, that claims to support speeds upto 200mbps, rest i don't know, 'cause i've thrown its box, which had rest of the specs.Its not made by a very well known company.
 
Is it possible to get two systems and the switch connected with store bought patch cables? That will rule out any intervening problems.
 
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