4.3 Reference points

23.6823GPPArchitecture enhancements to facilitate communications with packet data networks and applicationsRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

4.3.1 General

The following 3GPP reference points support the Indirect and Hybrid models of MTC and Service Capability Exposure.

NOTE: As further development of the MTC architecture takes place as well as when additional MTC common functionality and features are addressed, further reference points may be added.

4.3.2 List of Reference Points

The description of the MTC and Service Capability Exposure related reference points:

Tsms: Reference point used by an entity outside the 3GPP network to communicate with UEs used for MTC via SMS.

Tsp: Reference point used by a SCS to communicate with the MTC-IWF related control plane signalling.

T4: Reference point used between MTC-IWF and the SMS-SC in the HPLMN.

T6a: Reference point used between SCEF and serving MME.

T6b: Reference point used between SCEF and serving SGSN.

T6ai: Reference point used between IWK-SCEF and serving MME.

T6bi: Reference point used between IWK-SCEF and serving SGSN.

T7: Reference point used between IWK-SCEF and SCEF.

T8: Reference point used between the SCEF and the SCS/AS.

T9a: Reference point used between UCMF and AS.

T9b: Reference point used between UCMF and SCEF.

S6m: Reference point used by MTC-IWF to interrogate HSS/HLR.

S6n: Reference point used by MTC-AAA to interrogate HSS/HLR.

S6t: Reference point used between SCEF and HSS.

Rx: Reference point used by SCEF and PCRF. Functionality for Rx reference point is specified in TS 23.203 [27].

Ns: Reference point used between SCEF and RCAF.

Nt: Reference point used by SCEF and PCRF. Functionality for Nt reference point is specified in TS 23.203 [27].

Nu: Reference point used by SCEF to interact with the PFDF.

NOTE 1: Protocol assumption: User plane communication with SCS, for Indirect model, and AS, for Direct and Hybrid models, is achieved using protocols over Gi and SGi reference points. Control plane protocols over those reference points such as RADIUS/Diameter as specified in TS 29.061 [8] can also be supported towards the SCS.

NOTE 2: It is assumed that interfaces on the T6ai/T6bi/T7 reference points use the same protocol(s) as interfaces on the T6a/T6b reference points.

4.3.3 Reference Point Requirements

4.3.3.1 Tsp Reference Point Requirements

The Tsp reference point shall fulfil the following requirements:

– connects a MTC-IWF to one or more SCSs;

– supports the following device trigger functionality:

– reception of a device trigger request from SCS that includes an Application Port ID used by the UE to route the trigger internally to the appropriate triggering function;

NOTE 1: The Application Port ID can have different value for different applications.

– report to the SCS the acceptance or non-acceptance of the device trigger request;

– report to the SCS the success or failure of a device trigger delivery; and

– provides congestion/load control information to SCS as part of the response to device trigger requests.

– deliver a payload and application port ID received from the MTC-IWF and the external ID of the UE to SCS.

In addition, Domain Name System procedures similar to what is specified in TS 29.303 [9] may be used by the SCS for lookup and selection of which specific MTC-IWF to be used.

NOTE 2: Security requirements can be found in clause 4.8.

4.3.3.2 T4 Reference Point Requirements

The T4 reference point shall fulfil the following requirements:

– connects the MTC-IWF, taking the role of the SME, to SMS-SC inside HPLMN domain;

– supports the following device trigger functionality:

– transfer of device trigger, addressed by either an MSISDN or the IMSI, from MTC-IWF to SMS-SC inside HPLMN domain;

– transfer to the SMS-SC the serving SGSN/MME/MSC identity(ies) along with device trigger when addressed by IMSI; and

– report to MTC-IWF the submission outcome of a device trigger and the success or failure of delivering the device trigger to the UE.

– supports the delivering of SMS payload to SCS using Short Message Mobile Originated (MO-SMS) procedure via MTC-IWF.

4.3.3.3 Void

4.3.3.4 S6m Reference Point Requirements

The S6m reference point shall fulfil the following requirements:

– connect the MTC-IWF to HSS/HLR containing subscription and UE related information; and

– support interrogation of HSS/HLR to:

– map E.164 MSISDN or external identifier to IMSI;

– map IMSI and Application Port ID to external identifier;

– retrieve serving node information for the UE (i.e. serving SGSN/MME/MSC/IP-SM-GW identities); and

– determine if a SCS is allowed to send a device trigger to a particular UE.

NOTE: It is up to stage3 to define interworking between diameter-based s6m and map-based interface to the legacy HLR.

4.3.3.5 S6n Reference Point Requirements

The S6n reference point shall fulfil the following requirements:

– support communication between MTC-AAA and HSS/HLR containing subscription and UE related information; and

– support interrogation of HSS/HLR to:

– map between IMSI and External Identifier(s).

4.3.3.6 T6a/T6b Reference Point Requirements

The T6a and T6b reference points shall fulfil the following requirements:

– T6a connects the SCEF to the serving MME;

– T6b connects the SCEF to the serving SGSN;

– supports the following functionality:

– monitoring event configuration by the SCEF at the serving MME/SGSN;

– monitoring event reporting by the serving MME/SGSN to the SCEF.

– NIDD to/from the serving MME/SGSN.

4.3.3.7 S6t Reference Point Requirements

The S6t reference point shall fulfil the following requirements:

– connect the SCEF to HSS containing subscription and UE related information;

– monitoring event configuration/deletion by the SCEF at the HSS; and

– monitoring event reporting by the HSS to the SCEF.

– configuration/deletion of communication pattern parameters by the SCEF to HSS.

4.3.3.8 T6ai/T6bi Reference Point Requirements

The T6ai and T6bi reference points shall fulfil the following requirements:

– T6ai connects the IWK-SCEF to the serving MME;

– T6bi connects the IWK-SCEF to the serving SGSN;

– T6ai/T6bi support the following functionality:

– Monitoring Event reporting by the serving MME/SGSN to the IWK-SCEF;

– Forwarding of the Monitoring configuration information from the MME/SGSN to the IWK-SCEF.

– Forwarding of the NIDD configuration information from the MME to the IWK-SCEF;

– NIDD between the serving MME/SGSN and the IWK-SCEF.

4.3.3.9 T7 Reference Point Requirements

The T7 reference point shall fulfil the following requirements:

– connect the IWK-SCEF to the SCEF for Monitoring Event reporting.

– connect the IWK-SCEF to the SCEF for NIDD service.

4.3.3.10 Ns Reference Point Requirements

The Ns reference points shall fulfil the following requirements:

– Ns connects the SCEF to the RCAF;

– Ns supports the following functionality:

– request for network status by the SCEF;

– report of network status by the RCAF to the SCEF.

4.3.3.11 Nu Reference Point Requirements

The Nu reference point shall fulfil the following requirements:

– Nu connects the SCEF to the PFDF;

– Nu supports the following functionality:

– Provision, modification and removal of a subset or all of the Packet Flow Descriptions (PFDs) in the PFDF according to the instructions received from the SCS/AS.

4.3.3.12 T8 Reference Point Requirements

The T8 reference points shall fulfil the following requirements:

– connect one or more SCEF to one or more SCS/AS;

– use API-based communication model;

NOTE: The details of API aspects are left to Stage 3.

4.3.3.13 T9a/T9b Reference Point Requirements

The T9a and T9b reference points shall fulfil the following requirements:

– T9a connects the UCMF to an AS;

– T9b connects the UCMF to the SCEF;

– supports the following functionality:

– provisioning of RACS database information to the UCMF.