I've been banging my head against the wall for two years with this chronic problem. I bought an entirely new NIC to replace the old one, thinking that was the cause; the problem persists, regardless of NIC.
So, this is my problem:
I have a cable modem (old Motorola Surfboard), which, for the duration of what I will describe, indicates that it is powered on, connected to the network, and sending/receiving information from the outside world.
This modem is, in turn, connected to a D-Link DGL-4100 wired GbE router; this also will indicate network activity, on any connected ports (there are two, besides the WAN, for this description).
The router connects to two separate ethernet devices: A 3COM 3C2000 wired gigabit card, and an onboard Realtek RTL8169/8110 ethernet device (the device manager lists this as a GbE part, but this motherboard is an nForce2 board, and I doubt it's actually GbE).
Now, for the problem. During any internet usage, the network will suddenly drop off on the 3COM card, without any cause or indication; I'll be watching a video off YouTube or something, and the feed will stop streaming, or I'll be on AIM and get disconnected for no apparent reason. Originally, I attributed this to ISP throttling, since I only used to suffer this when I downloaded large amounts of data in a short period of time, but the problem has been occurring lately without any heavy bandwidth applications running (IRC and Firefox hardly qualify as saturating a gigabit network).
If I disable the 3COM device through the Network Connections window, I can reacquire the network with the RTL8169, but this will also fail after about an hour of usage, for no apparent reason.
Restarting resolves the problem temporarily, since it typically blows up after about an hour of use, and will continue to do so after any reboots.
Things I've ruled out:
Modem (like I said earlier, it's powered on and getting full connectivity for the duration of these incidents)
Router (also indicates connectivity during the network blackouts, and other computers can use the router after the blackout starts)
Static IP address (problem persists regardless of IP being static (as it is configured on the 3COM), or dynamic (as it is configured on the RTL8169))
Power management issues (I disabled the "allow computer to disable this device to save power" option, which reactivated the network for a short while but ultimately led to the same problem)
Cables (the network is working fine until the moment the network devices stop being able to receive any data, so it's not a cable problem)
Things I'm not sure about:
I can't /release or /renew either device once they stop being able to receieve data from the network. I can't figure out why, and it just times out during the operation.
3COM's diagnostic indicates that the NIC is working fine, but obviously it isn't since it isn't receiving any data.
Things I've done to try to fix the problem:
Replace the NIC. I've gone from an old Netgear 10/100 card to a D-Link 10/100 card, to the current 3C2000 card, and the problem persists across all NICs I stick in the computer. The problem also applies to the integrated network device, which is puzzling.
Replace the router. The DGL-4100 is an upgrade from an old, old Linksys 10/100 wired router, and the problem was just as bad on the old Linksys as it is now.
The only thing I haven't tried yet is replacing the cable modem itself, but I suspect this is a software issue more than a hardware issue, considering all the things I've ruled out so far.
Relevant hardware/software:
Windows XP Professional, SP2 with all patches (except for the latest WGA patch)
GigaByte GA-7N400 (nForce2 chipset)
Athlon XP 3200+ (Athlon XP 2800+ with a minor overclock, AGP/PCI frequencies locked at 66/33)
3COM 3C2000 GbE network card
Realtek RTL8169/8110
BFG 6800GT (not sure if this is relevant per se, but I want to rule out power fluctuations)
Antec 430W TruePower PSU
So, the conclusion: How do I fix this problem so that I don't have to keep restarting every two hours to stay on the internet?
So, this is my problem:
I have a cable modem (old Motorola Surfboard), which, for the duration of what I will describe, indicates that it is powered on, connected to the network, and sending/receiving information from the outside world.
This modem is, in turn, connected to a D-Link DGL-4100 wired GbE router; this also will indicate network activity, on any connected ports (there are two, besides the WAN, for this description).
The router connects to two separate ethernet devices: A 3COM 3C2000 wired gigabit card, and an onboard Realtek RTL8169/8110 ethernet device (the device manager lists this as a GbE part, but this motherboard is an nForce2 board, and I doubt it's actually GbE).
Now, for the problem. During any internet usage, the network will suddenly drop off on the 3COM card, without any cause or indication; I'll be watching a video off YouTube or something, and the feed will stop streaming, or I'll be on AIM and get disconnected for no apparent reason. Originally, I attributed this to ISP throttling, since I only used to suffer this when I downloaded large amounts of data in a short period of time, but the problem has been occurring lately without any heavy bandwidth applications running (IRC and Firefox hardly qualify as saturating a gigabit network).
If I disable the 3COM device through the Network Connections window, I can reacquire the network with the RTL8169, but this will also fail after about an hour of usage, for no apparent reason.
Restarting resolves the problem temporarily, since it typically blows up after about an hour of use, and will continue to do so after any reboots.
Things I've ruled out:
Modem (like I said earlier, it's powered on and getting full connectivity for the duration of these incidents)
Router (also indicates connectivity during the network blackouts, and other computers can use the router after the blackout starts)
Static IP address (problem persists regardless of IP being static (as it is configured on the 3COM), or dynamic (as it is configured on the RTL8169))
Power management issues (I disabled the "allow computer to disable this device to save power" option, which reactivated the network for a short while but ultimately led to the same problem)
Cables (the network is working fine until the moment the network devices stop being able to receive any data, so it's not a cable problem)
Things I'm not sure about:
I can't /release or /renew either device once they stop being able to receieve data from the network. I can't figure out why, and it just times out during the operation.
3COM's diagnostic indicates that the NIC is working fine, but obviously it isn't since it isn't receiving any data.
Things I've done to try to fix the problem:
Replace the NIC. I've gone from an old Netgear 10/100 card to a D-Link 10/100 card, to the current 3C2000 card, and the problem persists across all NICs I stick in the computer. The problem also applies to the integrated network device, which is puzzling.
Replace the router. The DGL-4100 is an upgrade from an old, old Linksys 10/100 wired router, and the problem was just as bad on the old Linksys as it is now.
The only thing I haven't tried yet is replacing the cable modem itself, but I suspect this is a software issue more than a hardware issue, considering all the things I've ruled out so far.
Relevant hardware/software:
Windows XP Professional, SP2 with all patches (except for the latest WGA patch)
GigaByte GA-7N400 (nForce2 chipset)
Athlon XP 3200+ (Athlon XP 2800+ with a minor overclock, AGP/PCI frequencies locked at 66/33)
3COM 3C2000 GbE network card
Realtek RTL8169/8110
BFG 6800GT (not sure if this is relevant per se, but I want to rule out power fluctuations)
Antec 430W TruePower PSU
So, the conclusion: How do I fix this problem so that I don't have to keep restarting every two hours to stay on the internet?