If your wireless connection signal is good, but you still see periodic latency spikes ranging from one every 20 seconds to one every 2 minutes, that situation is almost certainly caused by NetworkManager asking your wireless adapter to scan for wireless networks.
This is particularly annoying for those of you who are doing VoIP like Skype or Twinkle, engaging in Google Hangouts, or playing audio through the network to PulseAudio enabled stereos or speakers -- your audio and video drop out for quite a while, every minute or so. The same effect (but with less annoying consequences) can be seen during file transfers.
Well, good news. You can remedy this problem fairly straightforwardly, by switching to WICD. WICD does not tell your computer to scan for wireless networks if you're already connected (which seems like the most sensible behavior to me).
First, install WICD:
# install WICD yum install -y wicd wicd-curses wicd-gtk wicd-kde
Once installed, we'll replace NetworkManager with it. Again, very simple:
systemctl disable NetworkManager.service systemctl stop NetworkManager.service systemctl start wicd.service systemctl enable wicd.service
You're set now. Open the WICD user interface (
wicd-kde), connect to your wireless network, and that's it!
You can tell your desktop environment to start the WICD user interface every time you log in, but you shouldn't need to -- WICD will just connect to the wireless network on boot, no login required on your part.