6.4 MM Procedures

23.0603GPPGeneral Packet Radio Service (GPRS)Release 17Service descriptionStage 2TS

In A/Gb mode, the MM procedures shall use the LLC and RLC/MAC protocols for message transmission across the Gb and Um interfaces. The MM procedures shall provide information to the underlying layers to enable reliable transmission of MM messages on the Um interface. TS 43.064 [11] defines the mapping between LLC and the radio channels used.

In Iu mode, the MM procedures shall use the RANAP and RRC protocols for message transmission across the Iu and radio interfaces, respectively.

Furthermore, the MM procedures use MAP interfaces between Gn/Gp SGSN and HLR (Gr), and between SGSN and EIR (Gf), and a BSSAP+ interface between SGSN and MSC/VLR (Gs). Between S4-SGSN and HSS, the interface is Diameter based (S6d).

However, to assist with SGSN transition the use of MAP based Gr between the S4-SGSN and HSS is not precluded.

User data can in general be transmitted during MM signalling procedures. In A/Gb mode, user data transmitted during attach, authentication, and routeing area update procedures may be lost and may therefore have to be retransmitted. In order to minimise the need for retransmission, the MS and SGSN should not transmit user data during attach and authentication procedures. In case of routeing area update procedures, the user data transfer is allowed with restriction specified in description of these procedures in clauses and