There is a very tiny (extremely tiny, as tiny as a microbe) price you have to pay when you use a highly customizable desktop environment like KDE. I had issues with networking (which was more to do with my ignorance than KDE) under openSUSE KDE 12.1.
While the live version showed the network icon in the tray, once I installed it on my desktop it was gone. There was no Internet. I noticed this behavior only on the desktop, everything was fine on my laptop.
The reason being KDE defaults to YaST's Network setting if it detects that you are running a desktop.
In order to enable the network, you will have to open the network settings from YaST and configure your network cards in order for it to work. But, if you prefer the Networkmanager, where you can see a network icon on your tray you can change that too, easily.
Go to YaST network settings and change it from Tradition to Network manager and reboot your PC. Open the Network Configuration tool and enable wireless or wired connection as you wish.
To add it to the system tray, right click on the panel > Panel Options > Add widget and add Network Configuration. Now, you will see the network icon on the tray and you can manage connections easily.