Network load appears to cause dropped Internet access

I'm not sure if this is due to Vista, or some other external issue, but I find that when I'm doing a long download from the Internet my network connection will periodically shift to "local access only". The result is that my download is interrupted. Then a few moments later, my LAO connection switches back to Internet access. The connection will continue for a little while longer and then repeat the same cycle.

The downloading I'm doing can be a torrent file download,a large (over 100Mb) file from a shared file server, or streaming video.

I will see in the logs an entry like this:
Your computer was not able to renew its address from the network (from the DHCP Server) for the Network Card with network address 0016EADDA40A. The following error occurred: The semaphore timeout period has expired.. Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

This suggests to me either the cause or side effect of the lost Internet connection. This will happen sometimes when I'm going about my usual browsing of the Internet and increase in frequency when my traffic load increases.

Another thing: If I'm using a torrent download client, not only does this problem increase in frequency, after a few cycles I begin to get kicked off the wireless router completely. Vista will eventually reconnect automatically, but sometimes it does not and I have to disable/enable the wireless adapter for it to "clear out" and connect again.

My system is Vista Home Premium x64 on an HP laptop w/2.53GHz duo core processor and 4Gb RAM. I have a built-in Intel WiFi Link 5100 AGN card and built-in Realtec PCIe GBE controller, all with the most up to date drivers. My wireless router is a TP-Link TL-WR941ND. Note that this configuration was working fine for almost a year. It was only in the past couple of months that the problem cropped up. And I cannot pinpoint any specific event/change that would have caused this to happen.

Previously, I was having a lot of problems with my connection reverting to LAO (local access only) rather frequently without incurring much of a load... it took me a while to troubleshoot it and eventually I found that completely deleting my wireless network registration, rebooting, and then completely recreating my wireless network registration seemed to alleviate that problem. Apparently not completely, but certainly not nearly as bad as it was.


I've not had the opportunity to try out a Windows XP computer on my network as a basis of comparison. I'm looking at installing Virtual PC with an XP OS on my laptop, which should help me isolate it to the OS or external issue. Meanwhile, has anybody else seen these kinds of problems and have some suggestions?

Of course... just as one has a problem that mysteriously goes away when visiting the doctor, so does this problem. Today I performed another torrent file download (550mb). It went without a hitch. No lost connections. I even pegged a speed of 1.5Mb/s, this being on a wireless connection with 3-4 bars. Inconsistency is the nemesis of troubleshooting...

It appears this is happening with only one particular router, and when running a Vista OS. I've been able to verify reliable Internet access on some wireless routers, but one seems to periodically drop connections. It doesn't happen with Windows XP...

This thread can be closed. I upgraded the firmware on the wireless router and this seems to have solved the problem. Apparently there was a Vista-specific update that must have affected it.