LAN: 100% U/L Speed, 15% D/L speed, intermittant packet loss

[Omega]

So here's the problem: From Computer A, I can upload at nearly full network capacity (80% of 100 mbps full duplex) to Computer B. From Computer A, I can only download at an average of about 15% network capacity. On Computer A, packet loss alternates between 0% and 4% (sometimes it will be entirely fine for hundreds of pings, and other times it will experience consistent 4% packet loss). Switching network cables does not solve this problem (both cables are pre-made cables, one is STP CAT-5, one is UTP CAT-5e).


I'm not sure if this is related, but I have a Gigabyte GA-7VRXP, with onboard Realtek LAN. I disabled this in the BIOS, but when I installed Windows, it detected my PCI D-Link 530-TX+ as the Realtek whatever. I updated the drivers for it, with the appropriate D-Link drivers, which Windows accepted without problem.


I kind of thought that somehow there might be some EMI along the cable run (of about 7 ft), so I've identified some possible causes, but it doesn't seem that any of them are the culprit.

The original cable run passes by (within 1 foot of device):
-Internet Gateway Router (NAT Device, power cable, 802.11b adapter, two UTP CAT 5 runs)
-Cable Modem (Modem, power cable, cable)
-Lamp (Lamp w/ 60W bulb, power cable)
-Alarm Clock (Clock w/ radio and speaker, power cable)
-Computer B with open side (Computer, cords, power cable)
-Surge Protector (Protector w/ 5 running devices)
-Subwoofer (Sub, audio cable, power cable)
-Laser Printer (Printer, cord, power cable)
-Surge Protector (Four devices)
-Into Computer A (passes by lots of assorted cables, power cable)

For the second test run, when I was troubleshooting the problem, I ran a cable that passes by (within 1 foot of device) only the following:
-Internet Gateway Router (NAT Device, power cable, 802.11b adapter, two UTP CAT 5 runs)
-Computer B with open side (Computer, cords, power cable)
-Into Computer A (passes by lots of assorted cables, power cable)


Here's an overview of my setup:
Computer A:
AMD XP 1900+
512 MB PC2700 DDR
Gigabyte GA-7VRXP
D-Link 530-TX+ PCI
Windows XP Professional SP1

Computer B:
AMD T-Bird 1 GHz
256 MB PC133 SDRAM
ASUS A7V
Netgear FA311 PCI
Windows XP Professional SP1

Switch:
Compex NP 16


I'd really like to figure this problem out, because transferring many GB at <2 MB/sec is fairly annoying.

hmm
similar problem here

my comp A is Athlon 1.2GHz using SMC 10/100
running win2k sp3

comp B is P2-300MHz using D-Link 530-TX+ (same as urs)
running win98 se

Router
Macromate MSHR-8104
10/100 ADSL/cable 4 port router

cables are fine...
100 mbits light is on the router
no problem there

no ports restrictions or hiding

but when i want go to the drive directory page of comp B from comp A, it lags and the windows "busy" hourglass come up for that network explorer window
it "stalls" for approx 1 min then shows drive C and D
which are the drives on there

why is it so slow?
i dunno
but since Omega suggested EMI, im considering it too
because ive got too many wired running behind the comps along with the cat-5 cables

First thing I'ld do is run a direct crossover cable between the computers. That will eliminate the computers or the cable/hub issue. At least for a test. If it runs fine your computers are fine. Also it souldn't be EMI. I underline shouldn't because it still may be, but the construction of Lan cable's is such that the braiding is supposed to suppress EMI.

also EMI shouldn't affect the data 1 way....

something to do with full/half duplex maybe?

Agree, it's quite strange that EMI would only effect transmission one of the ways, which is why I was skeptical that was a cause. But then again, it doesn't seem like anything should be causing this problem...

I did try manually specifying 100 mbps full duplex on both computers with no change. I'm going to try manually specifying 100 mbps half duplex today, to see if that has any effect.

EMI is highly unlikely from the sources you mentioned.

The only common thing between the to problems is the d-link cards so that could be a problem.
But I'm thinking of a configuration problem in "File and Printer sharing" ,
Particularly the Browse maste and LM announce settings.
This may not apply to Omega's pure XP network, if NBT is set to off ( Using SMB only), and along tose lines I would check the firewall blocking of the needed ports.

tell me more please

i changed the LM announcement to Yes or Enabled instead of Auto something

still the same performance...