Severe Packet Loss Between Cable Modem and Computer

[yoda902]

Has any one had any experience with packet losses of 30-70% directly from the network adapter. I installed a second network card (both wired) and I am having the same exact issue with both.

Been running SmokePing tests on both my cable modem and my computer. Modem is spot on, no packet loss ~35ms. Computer is getting ~50% losses on average with ~80-90ms with spikes as high as 2s (2000ms). I have switched out cat5 to no avail. I have been unable to direct connect to another computer to isolate if the problem is on the modem output or network card/computer side.

Any assistance would be great.

 

[GhislainG]

The issue could be with the modem, but I don't understand your SmokePing test. Where does it run? At a remote site? It can't be local; otherwise a ping to the Ethernet port of your PC would take less than 1ms. I don't have cable, but with ADSL the PC would have a static or dynamic IP address provided by the ISP (and it shouldn't be any different with a cable modem). What happens if you using ping to ping your interface and then your ISP?

 

[yoda902]

The SmokePing test sends 20 packets every 300 seconds from 3 independant servers (1 in NY and 2 in Ca). It helps show line quality under a more constant load.

Pinging my IP from the computer shows <1ms and no losses. Pinging to ISP from my computer shows 10-20ms with high spikes and ~15-30% packet loss.

Additionally my laptop running XP seems to work just fine with no losses. So, I'm not sure having reinstalled the network adapters twice why they would be dropping packets like that.

Computer:
http://www.dslreports.com/r3/smokep...4e8f598c.NY&displaymode=n&Generate!=Generate!

Modem:
http://www.dslreports.com/r3/smokep...294c3d3b.NY&displaymode=n&Generate!=Generate!

 

[GhislainG]

What you call the modem is actually your ISP because your modem doesn't have an IP address. If you connect the laptop instead of the desktop, SmokePing works fine with no packet loss? Is that statement is correct, what desktop computer do you have?

 

[yoda902]

Yes, my laptop displays no latency/packet loss issues.

My desktop is a Lenovo A12 with Intel Dual Core ~1.6GHz each. 2GB Ram, ATI Radeon X700 running Vista

The network adapters are an integrated RealTek adapter and a Linksys LNE100TX PCI card. Both display the packet loss/high latency spike issue.

The modem is Comcast's standard (below 50Mbps) modem by Scientific Atlanta.

Again, I have never had issues with packet loss. I was previously on Georgia Tech's private network seeing no notable issues.

 

[GhislainG]

Connect the laptop and check the speed (10 or 100) and duplex mode (half or full). Then configure your desktop LAN interface with those parameters, e.g., 100 Mbps, half duplex and check if it resolves the issue.

 

[yoda902]

I will check this when I get home today. There are several other options under device properties for the network adapter, what do these other settings do? I saw a packet scheduler and some others if I remember right.

 

[GhislainG]

Leave the other settings alone. They can't help if all you have a modem.