Mobile radio interface layer 3 specification
This EN specifies the procedures used at the radio interface (Reference Point Um, see GSM 04.02) for Call Control (CC), Mobility Management (MM), Radio Resource (RR) management and Session Management (SM). The detailed descriptions of the protocols and the related procedures are described in GSM 04.18, TS 23.108 and TS 24.008.
When the notations for "further study" or "FS" or "FFS" are present in this ETS they mean that the indicated text is not a normative portion of this standard.
These procedures are defined in terms of messages exchanged over the control channels of the radio interface. The control channels are described in GSM 04.03.
The structured functions and procedures of this protocol and the relationship with other layers and entities are described in general terms in GSM 04.07.