Wireshark-users: Re: [Wireshark-users] Need some troubleshooting tips

From: Stephen Fisher <stephentfisher@xxxxxxxxx>
Date: Mon, 12 Mar 2007 17:41:20 -0700
On Sun, Mar 04, 2007 at 11:39:18AM -0800, Alan D. wrote:

> Months later I fineally realized that I was actually having lag spikes 
> in other games, the only difference was those games didn't completely 
> freeze me in place when a lag spike would occur.  Using Wireshark I 
> discovered that what is happening is at some point a packet is lost 
> and then resent as it should be, but following this there is what I 
> can only describe as a "TCP DUP ACK" storm, where the same ACK is sent 
> 10-200 times over a period of several seconds that coincides precisely 
> with the lag events experienced in games.

What protocol(s) is the game using?  UDP?  Does Wireshark tell you a 
packet is dropped right before the dup ack storm?  Are the dup acks 
going in both directions?  After this lag event, everything returns to 
normal?

> The following is a list of things I have tried so far to determine the 
> problem:
>
> 1) Replaced ethernet cable
> 2) Installed a Realtek 8139 NIC & disabled onboard NForce4 NIC
> 3) Replaced PIX 501 with a Windows 2000 RRAS server
> 4) Connected my PC directly to the modem (other systems in my house 
> work fine)
> 5) Complete reformat and reinstallation of latest drivers for all 
> hardware
> 6) Replaced motherboard with an MSI Neo4

Sounds like the only things left unchanged are the OS and the 
(cable/DSL) line and/or modem/router.  I would try to see if you get 
these lag spikes while doing other things that transfer a lot of data 
such as a file upload and a file download.


Steve