Need NIC to NIC Connection Help

[Phree337]

I'm working on getting my two computers to share a cable-modem and only want to use one IP (like I'm supposed to...). The cards I'm using are generic 10/100 NIC's with Realtek 8139 chips. I also have a D-Link DFE-530TX 10/100 going to the cable modem.

The problem: I want to run at 100Mb/s between the two computers and I only have a 10Mb/s hub. The cards work fine with the hub, but when I try to get a crossover cable to work directly between cards, no connection gets established. I'm wondering if this is an autosense problem.... Any ideas??

Thanks!

 

[rectifire]

Sounds like a cable problem. If no connection lights come on on the back of both nics when you try to hook them directly, it indicates a cabling problem.

Are you absolutely sure you have got yourself a crossover cable? What color is it (crossover cables are usually orange). Did you make the cable yourself? If so, do you know for a fact that you put it together correctly?

(I know, very simple....but every now and then even the best of us sometimes forget the basics )

 

[Phree337]

Yes, I made the cable myself. Took an ohm-meter and checked the pin-outs against a cable that was used on the network at work. The cross-over cable works when I connect it to the uplink port on the hub, so it's a good cable.

When I do hook it up, the lights on the NICs blink a few times, like they're trying to agree on a protocol to use. I'm just wondering if it is because they are both auto-sensing cards and can't agree on which speed.

 

[obenton]

If it is an autosense problem you could configure NICs at 100 full duplex, and if that doesn't work, 100 half-duplex.

 

[Phree337]

You know, I tried forcing the cards to 100Mb/s with and without the hub. Of course, with the hub all I could get was a bunch of collisions. I tried the diagnostics that came with the cards and got some pretty strange results (diags ran under pure DOS):

1) Both cards check out fine on board
2) No hardware conflict
3) No success on network test (sender, responder set-up), either card.

But yet I can get these cards to talk to each other under Linux and Win98, Win98 to Win98, Samba, etc.... This is the strangest thing I've ever seen!

I just thought I would pick someone else's brain for a while, see what comes up. Thanks for your replies!

 

[Ben]

Go here and make sure your cables follow the pattern in the diagram. How to Wire a Network

They must be in the proper sequence. Just because the lights come on, on the hub or on the card, doesn't mean your cable is OK.

And I have seen cheapie cables in stores that were wired incorrect, so I wouldn't follow thier example.

 

[cavingjan]

A crossover cable should not work correctly when hooked from the NIC to the uplink port on the hub. Sounds like you have a regular straight through cable. The wires should not be in the same order on both ends.
Regarding the hub, a hub in only capable of doing half duplex. Switches are required to allow computers to use full duplex. A crossover cable will also allow full duplex.

 

[Phree337]

OK, I have 1 to 3, 2 to 6, 3 to 1 and 6 to 2.... TX+ to RX+, TX- to RX-, both ways.... Is this correct for a X-over cable?

The hub I'm using X's the straight thru cables internally. The uplink does not, so a X-over cable connected to the uplink port is the same as a normal connected to the others. Correct?

I'm just trying to make sure I have a good understanding of this stuff....

 

[Ben]

Yes, that sounds correct. But I was wondering about which wires you used for the connections.

Just having the proper pins connected is not enough. You also have to use the proper color coding to prevent signal degredation.

For example, if you look at the picture, the orange pair is used for one set, and the green pair is used for the other.

Crossover Pic

 

[PirateX]

Just a suggestion, I have two realtek 8139a's and the 8139a chipset has problems running with windows 98, supposedely on mobo's with via chipsets. You could try grabbin another cheap nic and interswapping and see if that helps.