The present document describes the procedures used at the radio interface (Reference point Um, see ETSI TS 101 376-4-2 [6]) for Call Control (CC), of circuit switched services, Session Management (SM) for GMPRS services and Mobility Management (MM), and Radio Resource (RR) management for circuit switched and GMPRS services. These procedures are described in terms of messages exchanged over the control channels of the radio interface in the GMR-1 system. The control channels are described in ETSI TS 101 376-4-3 [7].

The structured functions and procedures of this protocol and the relationship with other layers and entities are described in general terms in ETSI TS 101 376-4-7 [11].

The present document does not cover the complete specifications but only describes where it differs from ETSI TS 101 376-4-8 (Release 1) [19] for circuit switched services and ETSI TS 124 008 [18] for packet services.

In the present document the clause numbering is based on the clause numbering in ETSI TS 101 376-4-8 (Release 1) [19]. When a clause of ETSI TS 101 376-4-8 (Release 1) [19] is not used, the GSM heading is retained and the words "This function is not currently supported in GMR-1" are inserted to maintain the numbering in subsequent clauses.

The messages and information elements defined in the present document are based on the GSM messages and information elements as defined in ETSI TS 101 376-4-8 (Release 1) [19]. In all cases, if a GMR-1 message or information element is defined, this GMR-1 definition takes precedence over the GSM definition. This precedence rule operates independently for messages and information elements and the GMR-1 defined information elements take precedence over the corresponding GSM definitions for all messages, including messages that have the same structure as GSM. For example, if a GMR-1 message is defined to be the same as the corresponding GSM message, this does not imply that all the information elements are the same as GSM.

The present document is based on ETSI TS 101 376-4-8 (Release 1) [19].