Heavy network traffic causes crash

[kkelley515]

I have a very simple home network, consisting of two machines. The first is a new linux box that acts as a router and connects to the outside world, and the second is an older machine that dual boots to linux or Win98.

The problem I'm having is that when I attempt to transfer a large file between the two machines, the older machine locks up with a pattern of vertical lines across the screen. This happens when the older machine is running MS or Linux. I have connected the two machines via an ethernet switch and directly with a crossover cable, and the problem persists.

I'm hoping that someone with more experience in setting up networks than I can shed some light as to a possible cause of this problem. Any help is appreciated.

 

[toffeapple]

what speed are the nic's?

 

[kkelley515]

The NICs are all 10/100 Mbit.

 

[Nodsu]

Those vertical lines and the cross-platformness of the problem show a serious hardware or issue. I would suggest testing the RAM of the older machine for starters.

 

[kkelley515]

Last night I was able to try out several things, none of which solved the problem.

First of all, I tested the system memory using memtest86, and it passed with flying colors.

I then checked for resource conflicts. None showed up. The only possibility would be that the NIC is using IRQ 10, which is also listed as a placeholder for the PCI steering. IRQ 9 is not currently in use on the system, but the system would not allow me to change the IRQ on the NIC.

I also attempted to slow down the network speed by specifying 10 Mbit half duplex on both machines, and reducing the recieve packet size on the older windows machine to 8k (lowest size available). Still no dice.

I'm not terribly familiar with NIC's in general. Could there be some sort of compatibility issue between the NIC and the main board? The card claims to be compatible with all OS...

A search of the internet also landed a suggestion that I fiddle around with the earlly Tx detection threshold, but I'm not exactly sure what that is or what the effect would be.

 

[Nodsu]

You could try putting the NIC in another PCI slot to make the BIOS assign another IRQ. Of course it could also be that the NIC is just gone bad.

 

[kkelley515]

I'll try moving the card after work today. The NIC should be fine (hopefully) since it is brand-spanking new. I had the same problem with another NIC that I bought a year ago, so I don't suspect that the network card is the problem.

Thanks for the help so far.

 

[kkelley515]

Some additional information:

Last night I disabled the firewalls on both machines to see if that had anything to do with it. Problem persists.

Ifconfig on the Linux gateway indicates that roughly 2/3 of the packets sent/recieved are resulting in packet collisions.

Also, the NIC in the older machine, as well as the NIC that in the machine before are both based on the RealTek 8139 chipset. Are there any known issues with this hardware?

 

[Nodsu]

Collisions? You should have none with full duplex. And very few with half duplex since you are transferring data in one direction. Maybe replace the cable and the NIC in the other end? BTW, brand newness does not mean a card can't be bad Get a replacement NIC and start ruling out faulty devices. Even better, get a third computer

 

[DelJo63]

Some additional information:
Ifconfig on the Linux gateway indicates that roughly 2/3 of the packets sent/recieved are resulting in packet collisions.

Normal networks have a max efficiency of 70% due to collisions (with or without duplexing) due to the base architecture. The device & software writes data without asking if the 'channel' is available (as in Token Ring) and then responds to the ACK or Lost Pack conditions (due to generated collision).

This says that you should NEVER see more than 35-40% max collision rate in a healthy network.

Investigate device driver updates, Cable replacements, OS updates, and
excessive memory usage during the transfers.

 

[kkelley515]

Nodsu: Third computer? I wish. Not in the budget right now.

I half suspect that the RealTek 8139 chipset is just too crappy for the older machine to handle. I suppose one probably gets what one pays for. Do you have any suggestions on a really good NIC that will be happier with an older and slower machine?

 

[DelJo63]

3com is always a good bet

 

[kkelley515]

I replaced the two RealTek chipset cards with a LinkSys EtherFast card. No problems now.

Thanks all for your help.