OS X laptop internet idle disconnect

[ZoomZoomZoom]

I remember having this same issue on my old powerbook. However, I don't remember how to fix it, and I haven't found the solution after fooling around with my system preferences.

Basically, when I leave my computer idle for a certain period of time, my internet connection disconnects. (My iChat logs out, etc.) When I get back, the internet reconnects again after a few seconds. I'm on a college ethernet connection.

Anyone know off the top of their head where I can disable this auto-disconnect with idle feature?

 

[Mernak]

Whenever the computer goes to sleep the airport is powered off to increase battery life, just go to System Preferences > Energy Saver and set it so it takes longer to sleep.