5.2 Protocol architecture

24.0073GPPGeneral AspectsMobile radio interface signalling layer 3Release 17TS

The protocol architecture is visualized for each of the four models:

– Figure 5.1/3GPP TS 24.007 shows the protocol architecture for a MS not supporting the GPRS service, restricting the representation of CM sublayer protocols to three paradigmatic examples, CC, SS, and SMS. The LCS protocol entity of a type A LMU would be included in the same manner. Note that the protocol stack for a class C GPRS service may be present in the MS, but it is not active simultaneously.

– Figure 5.2 shows the protocol architecture for a MS supporting the Class C GPRS service. (Note that the protocol stack for a circuit switched services may be present in the MS, but it is not active simultaneously).

– Figure 5.3 shows the protocol architecture for non-GPRS and GPRS-services supporting Class A and Class B MSs.

– Figure 5.4 shows the protocol architecture for a MS supporting CTS services in addition to non-GPRS services.

– Figure 5.5 shows the protocol architecture for a MS supporting the PS mode of operation UMTS service.

– Figure 5.6 shows the protocol architecture for UMTS services supporting CS/PS mode of operation MSs.

– Figure 5.7 shows the protocol architecture for a MS supporting EPS services.

– Figure 5.8 shows the protocol architecture for an MS supporting EPS services and CS fallback.

– Figure 5.9 shows the protocol architecture for a MS supporting 5GS services over 3GPP access.

– Figure 5.10 shows the protocol architecture for a MS supporting 5GS services over non-3GPP access.

NOTE: The LCS protocol entity for a type A LMU would be included in the figure in the same manner as the protocol entities for CC, SS and SMS.

Figure 5.1: Protocol Architecture not supporting GPRS service ‑ MS side

Figure 5.2: Protocol architecture supporting GPRS class C MSs, MS – side

Figure 5.3/3GPP TS 24.007: Protocol architecture supporting GPRS class A and B MSs, MS – side

Figure 5.4/3GPP TS 24.007: Protocol architecture supporting CTS services in addition to non- GPRS services, MS – side

Figure 5.5/3GPP TS 24.007: Protocol architecture of Non Access Stratum supporting PS mode of operation MSs, MS‑side

Figure 5.6/24.007: Protocol architecture of Non Access Stratum supporting CS/PS mode of operation MSs, MS – side

NOTE: SMS un-related parts of this figure, e.g. SNDCP should be modified for UMTS.

Figure 5.7/3GPP TS 24.007: Protocol architecture of Non Access Stratum supporting PS mode of operation MSs, MS‑side

Figure 5.8/3GPP TS 24.007: Protocol architecture of Non Access Stratum supporting CS/PS mode 1 or CS/PS mode 2 of operation MSs, MS‑side

Figure 5.9/3GPP TS 24.007: Protocol architecture of Non Access Stratum supporting MSs, MS‑side (over 3GPP access)

Figure 5.10/3GPP TS 24.007: Protocol architecture of Non Access Stratum supporting MSs, MS‑side (over non-3GPP access)

As shown in figure 5.1 a hierarchy of 3 sublayers is defined:

– the RR sublayer provides services to the MM sublayer and utilizes the services of signalling layer 2;

– the MM sublayer provides common services to the entities of the Connection Management (CM) sublayer;

– the CM sublayer includes, among others, the CC, SS, and SMS entities, which are independent entities.

Figure 5.2 defines four sublayers for GPRS services supporting Class C MSs:

– the RR sublayer provides services to the MM and LLC sublayers;

– the LLC sublayer provides services to the MM sublayer, the SNDCP and GSMS entities and uses services of the RR sublayer;

– the MM sublayer provides services to the SM and SS entities of the CM. The MM sublayer includes one GMM;

– the CM sublayer includes the SM, SS and GSMS entities. The SM entity provides services to the SNDCP entity and uses services of the MM sublayer. The GSMS entity is identical to the SMS entity for non-GPRS services except it uses the services from the LLC sublayer. The SS entity is identical to the one for non-GPRS services except it uses the services from the LLC or PS signalling connection.

Figure 5.3 defines four sublayers for non-GPRS and GPRS-services supporting Class A and Class B MSs:

– the RR sublayer provides services to the MM and LLC sublayers;

– the LLC sublayer provides services to the MM sublayer, the SNDCP and GSMS entities and uses services of the RR sublayer;

– the MM sublayer provides services to the SNDCP entity and to the entities of the Connection Management (CM) sublayer. In addition to the MM entity for non-GPRS services, the MM sublayer further includes one GMM entity;

– the CM sublayer includes, among others, the CC, SS, GSMS and SM entities, which are independent entities;

– the SM entity provides services to the SNDCP entity and uses services of the MM sublayer.
The GSMS entity is an extension of the SMS entity for non-GPRS services. For message transfer it uses the services both from the LLC sublayer and the MM entity of the MM sublayer. Furthermore it retrieves from the MM entity information about which transport service to use.

Figure 5.4 defines three sub-layers for CTS services:

– the RR sublayer provides services (including CTS services) to the MM sublayer and uses the services of signalling layer 2;

– the MM sublayer provides common services to the entities of the Connection Management (CM) sublayer; it provides also specific CTS services to the entities above CM;

– the CM sublayer includes, among others, the CC, SS, and SMS entities, which are independent entities.

Figure 5.5 defines three sublayers for UMTS PS domain services supporting PS mode of operation:

– the Access Stratum (AS) sublayer provides services to the MM sublayer and the RAB Manager (RABM) entity.

– the MM sublayer provides services to the SM, SS and GSMS entities of the CM. The MM sublayer includes one GMM entity;

– the CM sublayer includes the SM, SS and GSMS entities. The SM entity provides services to the RABM entity and uses services of the MM sublayer. The GSMS entity is identical to the SMS entity for GPRS services in GSM except it uses the services from the GMM sublayer. The SS entity is identical to the one for non-GPRS services except it uses the services from the LLC or PS signalling connection;

– the RABM hides the concepts of RABs that can be activated/released while a PDP context is active. If UL data in the terminal is to be sent on a RAB (NSAPI) that has been released the RABM will trigger a service request procedure in GMM.

Figure 5.6 defines three sublayers for UMTS CS domain services and UMTS PS domain services supporting CS/PS mode of operation MSs:

– the Access Stratum (AS) sublayer provides services to the MM sublayer and the RAB Manager (RABM) entity;

– the MM sublayer provides services to the entities of the Connection Management (CM) sublayer. In addition to the MM entity for CS domain services, the MM sublayer further includes one GMM entity;

– the CM sublayer includes, among others, the CC, SS, GSMS and SM entities, which are independent entities;

– the SM entity provides services to the RABM entity and uses services of the MM sublayer.
The GSMS entity is an extension of the SMS entity for CS domain services. For message transfer it uses the services both from the GMM entity of the MM sublayer and the MM entity of the MM sublayer. Furthermore it retrieves from the MM entity information about which transport service to use;

– the RABM hides the concepts of RABs that can be activated/released while a PDP context is active. If UL data in the terminal is to be sent on a RAB (NSAPI) that has been released, the RABM will trigger a service request procedure in GMM.

Figure 5.7 defines three sublayers for EPS PS domain services:

– the Access Stratum (AS) sublayer provides services to the MM sublayer;

– the MM sublayer provides services to the entities of the Connection Management (CM) sublayer. The MM sublayer further includes one EMM entity;

– the CM sublayer includes ESM entities;

– the ESM entity provides services to the Bearer Control (BC) entity and uses services of the MM sublayer;

– the BC entity hides the concepts of radio bearers that can be established/released while an EPS bearer context is active. If uplink data in the terminal is to be sent, and radio bearers have been released, the BC will trigger a service request procedure in EMM.

Figure 5.8 defines three sublayers for EPS domain services and non-EPS domain services supporting CS/PS mode 1 or CS/PS mode 2 of operation MSs:

– the Access Stratum (AS) sublayer provides services to the MM sublayer;

– the MM sublayer provides services to the entities of the Connection Management (CM) sublayer. In addition to the MM entity for non-EPS services, the MM sublayer further includes one EMM entity;

– the CM sublayer includes among others, the CC, SS, ESMS and ESM entities, which are independent entities;

– the ESM entity provides services to the Bearer Control (BC) entity and uses services of the MM sublayer.
The ESMS entity is an extension of the SMS entity for non-EPS services. For message transfer, it uses the services from the EMM entity of the MM sublayer;

– the BC entity hides the concepts of radio bearers that can be established/released while an EPS bearer context is active. If uplink data in the MS is to be sent, and all radio bearers have been released, the BC will trigger a service request procedure in EMM.

Figure 5.9 defines three sublayers for 5GS services:

– the NR or E-UTRA AS sublayer provides services to the 5GMM sublayer;

– the 5GMM sublayer provides services to the entities of the 5GCM sublayer. The 5GMM sublayer further includes one 5GMM entity;

– the 5GCM sublayer includes 5GSM entities;

– the 5GSM entity provides services to the QoS flow control (QFC) entity and uses services of the 5GMM sublayer;

– the QFC entity hides the concepts of radio resources that can be established, released or suspended while a 5GS context is active. If uplink data in the terminal is to be sent, and 5GS radio resources have been released or suspended, the QFC will notify 5GMM.

Figure 5.10 defines three sublayers for 5GS services:

– the Non-3GPP access stratum sublayer provides services to the 5GMM sublayer;

– the 5GMM sublayer provides services to the entities of the 5GCM sublayer. The 5GMM sublayer further includes one 5GMM entity;

– the 5GCM sublayer includes 5GSM entities;

– the 5GSM entity provides services to the QoS flow control (QFC) entity and uses services of the 5GMM sublayer;

– the QFC entity hides the concepts of non-3GPP access resources that can be established/released while a 5GS context is active. Whenever such resources are available, IPSec security associations will be established and maintained.