for control of connections in cellular telecommunication systems , particularly setting up and releasing of connections , it is checked whether a radio resource control connection is already active during setting up of anew mobility management connection . if an rrc connection is already active , explicit signaling is used . otherwise , rrc level events can be used to implicitly control mm level events . during releasing of mm connections , it is checked if another mm protocol uses rrc connections , and if that is the case , the releasing of mm connections is signaled explicitly .