What is TSN / RSN
I found a nice page about introduction of 802.1x.
Quotes of that page :
WPA is not the long term solution. To get a Robust Secure Network (RSN), the hardware must support and use CCMP. RSN is basically CCMP + 802.1X.
RSN, which uses TKIP instead of CCMP, is also called Transition Security Network (TSN). RSN may also be called WPA2, so that the market don’t get confused.
TSN = TKIP + 802.1X = WPA(1)
RSN = CCMP + 802.1X = WPA2