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Network becomes unusable when a specific computer downloads

Last response: in Networking
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December 24, 2011 2:48:18 PM

Hello,

I'm trying to pinpoint a problem on one of my computers: when a PC (Win-7) is downloading (be it p2p or other) it is slowing down the whole network for the other computers, even when downloading a low speeds 60kb/s when we have 10mb/s...

It's so bad that I can hardly load a page, when removing the download (on the PC) the speed on the other computers goes up INSTANTLY, done the test multiple times and the one computer is always the culprit. What could be the problem?
December 24, 2011 6:06:11 PM

Two things come to mind: (1) conflicting IP addresses - two machines with the same, (2) an incorrect subnet mask on the problem machine -- say a B class (255.255.0.0) instead of a C (255.255.255.0).

Either look at the LAN info page for your router or run ipconfig in the command prompt window to check these.

edit: oh and if the problem machine is wireless you may want to reinstall the wireless driver with latest version, I've seen them occasionally become corrupted.
December 25, 2011 3:00:50 AM

If all the computers are using wireless, that's the reason.

What you have to remember is that wireless access is serialized. It's no different than a walkie-talkie. Whenever someone is using the wireless frequency, all other wireless users have to wait until that wireless user ends their communications before the next user gets access. The fact that any given wireless user is consuming only a small portion of the available bandwidth is irrelevant. At any given moment that bandwidth is only available to the current wireless user! IOW, the battle is NOT for bandwidth, but wireless access time! Ironically, you’d be better off if the download PC was using MORE bandwidth and thus reducing its total access time.

That's why except for the convenience, in every other respect (performance, complexity, security, efficiency, etc.), wireless sucks.
!