This TS specifies the procedures used at the radio interface (Reference Point Um, see
) for Call Control (CC), Mobility Management (MM), and Session Management (SM).
These procedures are defined in terms of messages exchanged over the control channels of the radio interface. The
control channels are described in TS 44.003
The structured functions and procedures of this protocol and the relationship with other layers and entities are described in general terms in TS 24.007