Odd Periodic Connection Problems Over LAN

[tjmage1]

First I'll describe my current home network setup. I have two computers connected to a Linksys() router, sharing my satellite internet connection. Computer one is running Windows XP, and Computer two is running windows vista (home premium, 64bit). The satellite modem is connected via Ethernet cable to the router, and computer one is connected directly to the router with an ethernet cable. Computer two's connection to the router, however, goes through a Broadband over Power device before being connected to the router.



Here's the problem. Computer two has internet connectivity issues. These issues only occur in the evening (generally from 6pm or so on, though it's variable) AND if computer one is being used for internet activity (such as World of Warcraft, both computers play it). Earlier in the day both computers work fine for WoW and other activities. However, come evening computer two has issues.
These issues are rather variable. Most of the time it's working fine until it suddenly stops working. Most commonly, computer two is able to ping the router address with higher than usual response times and a high amount of missing packets. This results in webpages not loading, WoW not working, etc. Computer two is also unable to access the router's webpage (192.168.1.1, not the company's). However, other times internet broswing is simply slower with WoW not working, perhaps meaning fewer dropped packets. And then other times, computer two is unable to ping the router at all and can't even acquire an IP address from it. Again, these problems only occur in the evening and if the other computer is being used. If no one uses computer one, the problems go away.



What I've done to diagnose the problem: When the problem first appeared, in late May I believe, I thought the router to be at fault. After it died (cause unknown) I had an excuse to buy a new one, which I did. It was set up in the same way, but problems consisted after installation of the new router. Thinking perhaps computer two was infected or something, I downloaded Ubuntu 9.04 and tested computer two's connection with it. The problems did not go away on the alternative operating system. I then called my ISP, who blamed the router after discovering that I was unable to acquire an IP address from the router. However, given that the problem consisted through two different routers (different brand, different quality), I think that the router being the cause is unlikely. Given that the problem persisted through an OS swap, I don't think computer two's software is at fault. Also, my portable Cowon device is also having problems at the same time as computer two.



Attempted solutions and what I've done. One change I made was changing the router and computer two's MTU table size to the optimal satellite settings (which I determined after using pings of various sizes on websites while bypassing the router and setting the “don't fragment” flag). This was unhelpful, though it might have lowered my lag a bit, I'm not sure. I've checked both computers to see if there was a program that might start running in the evening and cause problems, but I was unable to find anything. I've virus scanned both computers.


Possible explanations and tests thereof. One thought is that my ISP is overloaded in the evening and this is somehow passed to my router, giving it problems. Given that the problem developed out of the blue and the time sensitive nature of it, this is my theory. If this is the case, then I don't see any solution other than a more expensive router that might not work anyway. Another is my router is somehow either compromised/hacked or a setting is interfering with my computer. Naturally, I checked for such a setting, but was unable to find anything. My next step will be to reset the router (I've already upgraded the firmware) and reinstall it in the network. Other than that, computer one could somehow be causing the problem, though I have no idea how. Perhaps a program that I couldn't find is overloading the router?

One potential way to eliminate both computer one and the router being at fault is to connect computer two directly to the satellite modem and see if the problem persists. If it does persist, then I know the problem is with computer two or the ISP, if not, then the router or computer one (assuming no complex interplay factors). Such a test is hard to conduct, but valuable for the results.


What I want to know is, basically, what can I do? What tests should I conduct to help with a diagnosis? Is there anything I can do to resolve the problem? What other information can I give to help you come to a conclusion?

[tjmage1]

bump.