5.1 Basic configuration

23.0023GPPNetwork architectureRelease 17TS

The basic configuration of a Public Land Mobile Network (PLMN) supporting GPRS and the interconnection to the PSTN/ISDN and PDN is presented in figure 1 and figure 1a. Whereas the basic configuration of a Public Land Mobile Network (PLMN) supporting PS Domain (both GPRS and EPC) and the interconnection to the PSTN/ISDN and PDN is presented in figure 1b. This configuration presents signalling and user traffic interfaces which can be found in a PLMN. Implementations may be different: some particular functions may be gathered in the same equipment and then some interfaces may become internal interfaces.

In the basic configuration presented in figure 1, all the functions are considered implemented in different equipment. Therefore, all the interfaces within PLMN are external. Interfaces A and Abis are defined in the 48-series of Technical Specifications. Interfaces Iu, Iur and Iub are defined in the 25.4xx-series of Technical Specifications. Interfaces B, C, D, E, F and G need the support of the Mobile Application Part of the signalling system No. 7 to exchange the data necessary to provide the mobile service. No protocols for the H-interface and for the I-interface are standardized. All the GPRS-specific interfaces (G- series) are defined in the 23-series, 24-series and 29-series of Technical Specifications. Interfaces Mc, Nb, and Nc are defined in TS 23.205 [43] and in the 29-series of Technical Specifications. The specifications for E-UTRAN interfaces S1 and X2 are specified in TS 36.4xx and NAS protocol is specified in TS 24.301 [89] series of specifications. The interfaces S6a/d/S13 are specified in the specifications TS 29.272 [86]. The EPC specific S1/3/4/5/8/10/11/12/ series are specified in TS 29.274 [90] for GTP based protocols and for PMIP based S5/8 interfaces are specified in TS 29.275 [93].

From this configuration, all the possible 3GPP access PLMN organisations can be deduced. In the case when some functions are contained in the same equipment, the relevant interfaces become internal to that equipment.

The configuration possibilities when using non-3GPP access technologies using EPS is not part of the scope of this specification. The architecture and details for non-3GPP access and mobility and interworking with non-3GPP access are described in TS 23.402 [77] and the interfaces and protocols are specified in 3GPP 24-series and 29-series of specifications..


Bold lines: interfaces supporting user traffic;

Dashed lines: interfaces supporting signalling.

NOTE 1: The figure shows direct interconnections between the entities. The actual links may be provided by an underlying network (e.g. SS7 or IP): this needs further studies.

NOTE 2: When the MSC and the SGSN are integrated in a single physical entity, this entity is called UMTS MSC (UMSC).

NOTE 3: A (G)MSC server and associated CS-MGW can be implemented as a single node: the (G)MSC.

NOTE 4: The Gn interface (between two SGSNs) is also part of the reference architecture, but is not shown for layout purposes only.

Figure 1: Basic Configuration of a PLMN supporting CS and PS services (using GPRS) and interfaces

Figure 1a: Configuration for Short Message Service

NOTE 1: The interfaces in blue represent EPS functions and reference points.

NOTE 2: The S-GW and PDN-GW can be further split into control plane entities (SGW-C and PGW-C) and user plane entities (SGW-U and PGW-U). The architecture reference model for the control plane and user plane separation is defined in TS 23.214 [145].

Figure 1b: Basic Configuration of a 3GPP Access PLMN supporting CS and PS services (using GPRS and EPS) and interfaces