In the past few weeks, I've noticed my network connection becoming unstable while downloading files. I'm not sure how to diagnose this issue.

I've found that my network connections appear to be temporarily unresponsive (for periods up to a minute or so) while I'm downloading a file (that's large enough to not be downloaded instantly). The problem occurs when downloading data through a webbrowser, but also when using SCP to download data from a remote location.

During the period in which network connections are unresponsive, every resource that I try to access over the network is unavailable. This includes:

• The download itself (SCP reports a 'stalled' download)
• Web pages (won't load - browsers report 'resource unavailable')
• SSH sessions (CLI freezes)
• VPN connections (connections terminate)
• IM client connections (client starts reconnection attempts)
• ... (everything is pretty much dead)

I've noticed that during such a period, I cannot even access the (web-based) administrative console of the router on my LAN at home (although it remains reachable for other devices).

The problem occurs when connected to my home network, but also when I'm in the office. Other devices than my laptop are not affected.

Given the above two characteristics I assume the problem cause lies within my laptop, not the network infrastructure.

I'm running Ubuntu 11.10. Apart from applying automatic updates from Ubuntu, I can't think of a change that I applied to the OS that could have started the problems. I'm absolutely positive that this issue did not occur up to a few weeks ago (as it's very noticeable, and only started to annoy me in the last few days).

When the problem occurs, applications that make use of a network connection fail visibly (I get popups telling me that a VPN connection is broken, for instance). The network manager does not report any issues related to my wifi-connection though. Help?