knetworkmanager is a Network Manager for KDE4. It is hated or liked by users and usually not in between. I personally like it although it has its fair share of bugs. But I like Mandriva's net_applet more. It is stable and more reliable. It is prefered by many Mandriva users. However, if you are stuck with recent problems (bug?) of perl in Mandriva Cooker like me, you are forced to use command line of wpa_supplicant or iwconfig or using gui application like knetworkmanager.
In Mandriva, you can change which network manager control the wireless connection by changing the option in net_applet or you can manually change in file /etc/sysconfig/network-scripts/ifcfg-wlan0. If you want knetworkmanager in control of it, you just have to change this line to yes: