This European Telecommunication Standard (ETS) specifies the procedure s used at the radio interface (Reference Point Um, see GSM 04.02) for Call Control (CC), Mobility Management (MM) and Radio Resource (RR) ma nagement. 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 c ontrol channels of the radio interface. The control channels are descr ibed in GSM 04.03. The structured functions and procedures of this protocol and the relat ionship with other layers and entities are described in general terms in GSM 04.07. 0.1Scope of the Technical Specification The procedures currently described in this ETS are for the call contro l of circuit-switched connections, mobility management and radio resou rce management. GSM 04.10 contains functional procedures for support of supplementary services. GSM 04.11 contains functional procedures for support of point-to-point short message services. GSM 04.12 contains functional description of short message - cell broa dcast. NOTE:layer 3 includes the functions and protocols described in this ETS. The terms data link layer and layer 2 are used interchangeab ly to refer to the layer immediately below layer 3. 0.2Application to the interface structures The layer 3 procedures apply to the interface structures defined in GS M 04.03. They use the functions and services provided by layer 2 defin ed in GSM 04.05 and 04.06. GSM 04.07 gives the general description of layer 3 including procedures, messages format and error handling. 0.3Structure of layer 3 procedures A building block method is used to describe the layer 3 procedures. The basic building blocks are elementary procedures provided by the protocol control entities of the three sublayers, i.e. radio resource management, mobility management and connection management sublayer. Complete layer 3 transactions consist of specific sequences of element ary procedures. The term structured procedure is used for these sequ ences. 0.4Test procedures Test procedures of GSM radio interface signalling are described in GSM 11.10 and 11.20. 0.5Use of logical channels The logical control channels are defined in GSM 05.02. In the followin g those control channels are considered which carry signalling informa tion or specific types of user packet information: (i)Broadcast Control CHannel (BCCH): downlink only, used to broadcast Cell specific information; (ii)Synchronization CHannel (SCH): downlink only, used to broadcast sy nchronization and BSS identification information; (iii)Paging CHannel (PCH): downlink only, used to send page requests t o Mobile Stations; (iv)Random Access CHannel (RACH): uplink only, used to request a Dedic ated Control CHannel; (v)Access Grant CHannel (AGCH): downlink only, used to allocate a Dedi cated Control CHANNEL; (vi)Stand Alone Dedicated Control CHannel (SDCCH): bi-directional; (vii)Fast Associated Control CHannel (FACCH): bi-directional, associat ed with a Traffic CHannel; (viii)Slow Associated Control CHannel (SACCH): bi-directional, associa ted with a SDCCH or a Traffic CHannel; (ix)Cell Broadcast CHannel (CBCH): downlink only used for general (not)