My laptop uses CentOS 6.3 with kernel 2.6.32-279.el6.x86_64. My wireless adaptor is Intel Corporation Centrino Wireless-N 1000.

My wireless connection always get off after about 20 minutes. The network applet shows the connection is still on with good signal strength, but I just cannot load any web pages even the configuration page of the wireless router.

The problem will continue until I disable and reconnect the wireless.

Other devices like my cell phone uses the same wireless network without the problem. Even yesterday I'm using the same laptop with Fedora 17 without this problem.

I also searched the internet and someone said running services NetworkManager and network simultaneously may be a problem. But I cannot stop any one of them because: if I stop network and start NetworkManager, the network service will start automatically; if I stop NetworkManager and run network, it says "Device does not seem to be present, delaying initialization." when trying to bringing on the wireless.

What shall I do to get rid of the problem? Thank you very much!