6 Network Function Service procedures

23.6323GPPRelease 18Stage 2TSUser data interworking, coexistence and migration

6.1 HSS Services

6.1.1 General

The following table illustrates the HSS Services.

Table 6.1.1-1: NF services provided by HSS

NF service

Service Operations

Operation Semantics

Example Consumer(s)

UE Authentication

Get

Request/Response

UDM

UECM

SNDeregistration

Request/Response

UDM

Update

Request/Response

UDM

SDM

Get

Request/Response

UDM

Subscribe

Subscribe/Notify

UDM

Unsubscribe

Notify

EE

Subscribe

Subscribe/Notify

UDM

Unsubscribe

Notify

6.1.2 Nhss_UEAuthentication service

6.1.2.1 Nhss_UEAuthentication_Get service operation

Service operation name: Nhss_UEAuthentication_Get

Description: Requester NF gets the authentication vector from HSS. For AKA based authentication, this operation can be also used to recover from synchronization failure situations.

Inputs, Required: IMSI, authentication method, serving network name.

Inputs, Optional: Synchronization Failure indication and related information (i.e. RAND/AUTS).

Outputs, Required: Authentication vector.

Outputs, Optional: None.

6.1.3 Nhss_UECM service

6.1.3.1 Nhss_UECM_SNDeregistration service operation

Service operation name: Nhss_UECM_SNDeregistration.

Description: The NF consumer requests the HSS to initiate cancel location to the Serving Node registered in HSS serving the UE in EPS and/or PS, if any.

Inputs, Required: IMSI, deregistration reason.

Inputs, Optional: None.

Outputs, Required: Result Indication.

Outputs, Optional: None.

6.1.3.2 Nhss_UECM_Update service operation

Service operation name: Nhss_UECM_Update.

Description: The NF consumer informs the HSS about an update in the UE Context (e.g. a change in the IMEI).

Inputs, Required: IMSI.

Inputs, Optional: IMEI(SV), serving PLMN.

Outputs, Required: Result Indication.

Outputs, Optional: None.

6.1.4 Nhss_SDM service

6.1.4.1 Nhss_SDM_Get service operation

Service operation name: Nhss_SDM_Get

Description: The consumer NF gets the subscriber data indicated by the requested data type from HSS. In this release, only the PGW-C+SMF FQDN for S5/S8/S2b interface information is supported as requested data type.

Inputs, Required: IMSI, requested data.

Inputs, Optional: None.

Outputs, Required: The consumer NF gets the requested subscription data

Outputs, Optional: None.

6.1.4.2 Nhss_SDM_Notification service operation

Service or service operation name: Nhss_SDM_Notification

Description: The HSS notifies NF consumer of the updates of the subscriber data indicated by the "subscription data Type" input. In this release, only the PGW-C+SMF FQDN for S5/S8/S2b interface information is supported as subscription data type.

Inputs, Required: IMSI, Subscription data type(s).

Inputs, Optional: None.

Outputs, Required: Result Indication.

The HSS invokes this service operation under the following cases:

– When the PGW-C+SMF FQDN for S5/S8/S2b interface information is updated at the HSS, the updated information is notified to the NF consumer that has subscribed for the specific subscription data type to be notified.

Outputs, Optional: None.

6.1.4.3 Nhss_SDM_Subscribe service operation

Service operation name: Nhss_SDM_Subscribe

Description: The NF consumer subscribes for updates to the subscriber data indicated by the ‘subscription data type’ input. The HSS shall check the requested consumer is authorized to subscribe to requested updates. In this release, only the PGW-C+SMF FQDN for S5/S8/S2b interface information is supported as subscription data type.

Inputs, Required: IMSI, Subscription data type(s).

Inputs, Optional: None.

Outputs, Required: None.

Outputs, Optional: None.

6.1.4.4 Nhss_SDM_Unsubscribe service operation

Service operation name: Nhss_SDM_Unsubscribe

Description: The NF consumer unsubscribes from updates to the subscriber data indicated by the ‘subscription data type’ input. In this release, only the PGW-C+SMF FQDN for S5/S8 interface information is supported as subscription data type.

Inputs, Required: IMSI, Subscription data type(s).

Inputs, Optional: None.

Outputs, Required: None.

Outputs, Optional: None.

6.1.5 Nhss_EE service

6.1.5.1 Nhss_EE_Subscribe service operation

Service operation name: Nhss_EE_Subscribe.

Description: The NF consumer request the HSS to subscribe to notifications for monitoring events as described in 3GPP TS 23.682 [16] (e.g. location change).

Inputs, Required: IMSI, monitoring event type(s), notification address.

Inputs, Optional: –

Outputs, Required: Result Indication, Subscription ID.

Outputs, Optional: None.

6.1.5.2 Nhss_EE_Unsubscribe service operation

Service operation name: Nhss_EE_Unsubscribe.

Description: The NF consumer request the HSS to delete the subscription of a monitoring event.

Inputs, Required: Subscription ID.

Inputs, Optional: –

Outputs, Required: Operation execution result indication.

Outputs, Optional: None.

6.1.5.3 Nhss_EE_Notify service operation

Service operation name: Nhss_EE_Notify.

Description: The HSS reports the monitoring event to the consumer that has previously subscribed.

Inputs, Required: Event ID, Notification Correlation Information, time stamp.

Inputs, Optional: Event specific parameters list.

Outputs, Required: None.

Outputs, Optional: None.

6.2 UDM Services

6.2.1 General

The following table illustrates the UDM Services.

Table 6.2.1-1: NF services provided by UDM

NF service

Service Operations

Operation Semantics

Example Consumer(s)

UECM

P-CscfRestorationTrigger

Request/Response

HSS

Get

Request/Response

HSS

AMFDeregistration

Request/Response

HSS

Update

Request/Response

HSS

MT

ProvideDomainSelectionInfo

Request/Response

HSS

ProvideUserState

Request/Response

HSS

ProvideLocationInfo

Request/Response

HSS

Provide5GSRVCCInfo

Request/Response

HSS

EventExposure

Subscribe

Subscribe/Notify

HSS

Notify

UEAU

GetHssAv

Request/Response

HSS

SDM

Get

Request/Response

HSS

Subscribe

Subscribe/Notify

HSS

Unsubscribe

Notify

PP

Update

Request/Response

HSS

6.2.2 Nudm_UECM service operation

6.2.2.1 Nudm_UECM_P-CscfRestorationTrigger service operation

Service operation name: Nudm_UECM_P-CscfRestorationTrigger

Description: Requester NF (HSS) triggers the UDM to notify all NFs (AMF, SMF) that have previously subscribed to receive notifications for P-CSCF restoration.

Inputs, Required: SUPI.

Inputs, Optional: None.

Outputs, Required: None.

Outputs, Optional: None.

6.2.2.2 Nudm_UECM_Get service operation

See 3GPP TS 23.502 [5] clause 5.2.3.2.4.

6.2.2.3 Nudm_UECM_AMFDeregistration service operation

Service operation name: Nudm_UECM_AMFDeregistration.

Description: The NF consumer requests the UDM to initiate deregistration of the AMF serving the UE, if any.

Inputs, Required: SUPI, deregistration reason.

Inputs, Optional: None.

Outputs, Required: Result Indication.

Outputs, Optional: None.

6.2.2.4 Nudm_UECM_Update service operation

See 3GPP TS 23.502 [5] clause 5.2.3.2.5.

6.2.3 Nudm_MT Service

6.2.3.1 Nudm_MT_ProvideDomainSelectionInfo Service

Service operation name: Nudm_MT_ProvideDomainSelectionInfo

Description: Provides the UE information for terminating domain selection of IMS voice in 5G to the consumer NF (HSS).

Inputs, Required: SUPI.

Inputs, Optional: None.

Outputs, Required: Success/Failure indication.

Outputs, Optional: Indication of supporting IMS voice over PS Session or not, Time stamp of the last radio contact with the UE, Current RAT type.

6.2.3.2 Nudm_MT_ProvideUserState service operation

Service operation name: Nudm_MT_ProvideUserState

Description: Provides the UE’s 5GS PS User State to the consumer NF (HSS).

Inputs, Required: SUPI.

Inputs, Optional: None.

Outputs, Required: Success/Failure indication.

Outputs, Optional: 5GS User State.

6.2.3.3 Nudm_MT_ProvideLocationInfo service operation

Service operation name: Nudm_MT_ProvideLocationInfo

Description: Provides the UE’s 5GS location information to the consumer NF (HSS).

Inputs, Required: SUPI, Current Location Indicator, Serving Node Indication, Local Time Zone Indication, and RAT-Type requested Indicator.

Inputs, Optional: None.

Outputs, Required: Success/Failure indication.

Outputs, Optional: 5GS location information.

6.2.3.4 Nudm_MT_Provide5GSRVCCInfo Operation

Service operation name: Nudm_MT_ProvideSRVCCInfo

Description: Provides the UE PS to CS SRVCC capability for the UE to the consumer NF (HSS).

Inputs, Required: SUPI.

Inputs, Optional: None.

Outputs, Required: Success/Failure indication.

Outputs, Optional: Indication of the UE supporting SRVCC capability or not, If the 5GS supports 5G-SRVCC, an STN-SR and a C-MSIDSN.

6.2.4 Nudm_EE Service

6.2.4.1 Nudm_EventExposure_Subscribe service operation

See 3GPP TS 23.502 [5] clause 5.2.3.5.2.

When used by the HSS in MT-SMS delivery failure scenarios (see clause 4.6.3) the subscribe request shall be a one-time subscription for UE-reachability for SMS and shall indicate whether it is applicable to 3GPP access, Non3GPP access or both.

6.2.4.2 Nudm_EventExposure_Notify service operation

See 3GPP TS 23.502 [5] clause 5.2.3.5.4.

When used by the HSS in SMS Alerting scenarios (see clause 4.6.4) the notify request shall indicate whether it is applicable to 3GPP access or Non3GPP access.

6.2.5 Nudm_UEAuthentication service

6.2.5.1 Nudm_UEAuthentication_GetHssAv service operation

Service operation name: Nudm_UEAuthentication_GetHssAv

Description: Requester NF gets the authentication vector from UDM. For AKA based authentication, this operation can be also used to recover from synchronization failure situations.

Inputs, Required: SUPI, authentication method (e.g. EAP-AKA’, EPS-AKA, IMS-AKA, GBA-AKA), serving network name.

Inputs, Optional: Synchronization Failure indication and related information (i.e. RAND/AUTS).

Outputs, Required: Authentication vector.

Outputs, Optional: None.

6.2.6 Nudm_SDM service operations

6.2.6.1 Nudm_SDM_Get service operation

See 3GPP TS 23.502 [5] clause 5.2.3.3.2.

6.2.6.2 Nudm_SDM_Subscribe service operation

See 3GPP TS 23.502 [5] clause 5.2.3.3.4.

6.2.6.3 Nudm_SDM_Unsubscribe service operation

See 3GPP TS 23.502 [5] clause 5.2.3.3.5.

6.2.6.4 Nudm_SDM_Notify service operation

See 3GPP TS 23.502 [5] clause 5.2.3.3.3.

6.2.7 Nudm_PP service operations

6.2.7.1 Nudm_PP_Update service operation

Service operation name: Update

Description: Removes, provides or modifies the STN-SR, CMSISDN, if the 5GS support 5G-SRVCC.

Inputs, Required: None.

Inputs, Optional: SUPI, STN-SR, CMSISDN.

Outputs, Required: Success/Failure indication.

Outputs, Optional: None.

6.3 UDR Services

The UDM and optionally the HSS shall make use of the Nudr_DataRepository Query service operations specified in 3GPP TS 23.502 [5] to retrieve Authentication Subscription Data. If the subscribed authentication method is 5G_AKA or EAP_AKA_PRIME, the AuthenticationSubscriptionData shall include an indicator indicating whether for the identified subscriber authentication vector generation is to be performed by the HSS.

Annex A (informative):
Change history

Change history

Date

Meeting

TDoc

CR

Rev

Cat

Subject/Comment

New version

2019-04

CT4#90

C4-191319

Skeleton

0.1.0

2019-04

CT4#90

C4-191320

Scope

0.2.0

2019-04

CT4#90

C4-191321

Reference Architecture

0.2.0

2019-05

CT4#91

C4-192135

Removal of Editor’s Note

0.3.0

2019-05

CT4#91

C4-192402

P-CSCF Restoration

0.3.0

2019-05

CT4#91

C4-192403

T-ADS

0.3.0

2019-05

CT4#91

C4-192405

SMS

0.3.0

2019-05

CT4#91

C4-192462

Authentication

0.3.0

2019-05

CT4#91

C4-192098

Authentication – HSS using Nudr

0.3.0

2019-09

CT4#93

C4-193134

System Architecture

0.4.0

2019-09

CT4#93

C4-193137

IMS procedures

0.4.0

2019-09

CT4#93

C4-193829

Mobility procedures

0.4.0

2019-09

CT4#93

C4-193556

Authentication vector generation in UDM

0.4.0

2019-09

CT4#93

C4-193297

MT-SMS Routing Information Retrieval Over Nudr

0.4.0

2019-09

CT4#93

C4-193617

Location Info Retrieval

0.4.0

2019-09

CT4#93

C4-193618

UE reachability

0.4.0

2019-09

CT4#93

C4-193619

User State Info Retrieval

0.4.0

2019-10

CT4#94

C4-194347

ProvideLocationInformation

0.5.0

2019-10

CT4#94

C4-194348

Document cleanup

0.5.0

2019-10

CT4#94

C4-194350

IMS Use Cases Correction

0.5.0

2019-10

CT4#94

C4-194252

N26 Editor’s Note Removal

0.5.0

2019-11

CT4#95

C4-195416

HSS to 5GS-UDR reference point

0.6.0

2019-11

CT4#95

C4-195020

P-CSCF restoration

0.6.0

2019-11

CT4#95

C4-195420

Clarification on Mobility, IMS and SMS

0.6.0

2019-11

CT4#95

C4-195137

P-CSCF Restoration Procedure

0.6.0

2019-11

CT4#95

C4-195138

Nudm_UEAuthentication service operations

0.6.0

2019-11

CT4#95

C4-195428

Nudm_SDM Service

0.6.0

2019-11

CT4#95

C4-195429

SMS Procedures

0.6.0

2019-12

CT#86

CP-193066

TS presented for information and approval

1.0.0

2019-12

CT#86

CP-193296

A title corrected

1.0.1

2019-12

CT#86

TS was approved

16.0.0

2020-03

CT#87e

CP-200227

0008

2

F

Reference Points

16.1.0

2020-03

CT#87e

CP-200019

0001

1

F

HSS can be consumer of Nudr

16.1.0

2020-03

CT#87e

CP-200019

0002

1

F

UserState retrieval

16.1.0

2020-03

CT#87e

CP-200019

0004

2

B

PGW-C+SMF Information Notification Procedure

16.1.0

2020-03

CT#87e

CP-200019

0011

B

IMEI Retrieval

16.1.0

2020-03

CT#87e

CP-200022

0006

4

B

Introduce 5G SRVCC support

16.1.0

2020-06

CT#88e

CP-201033

0003

2

F

SMS

16.2.0

2020-06

CT#88e

CP-201033

0013

F

Authentication Options

16.2.0

2020-06

CT#88e

CP-201033

0014

2

B

Common Network Exposure

16.2.0

2020-06

CT#88e

CP-201033

0015

6

F

UDM and HSS not Aware of N26

16.2.0

2020-06

CT#88e

CP-201033

0016

F

Association between APN and PGW-C+SMF FQDN in HSS

16.2.0

2020-06

CT#88e

CP-201033

0018

1

F

SMS Interfaces

16.2.0

2020-06

CT#88e

CP-201033

0019

B

Support of SMSoIP

16.2.0

2020-06

CT#88e

CP-201036

0017

F

Remove Editor’s Note regarding multiple SRVCC capabilities per system

16.2.0

2020-09

CT#89e

CP-202111

0022

F

Removal Of Editor’s Notes

16.3.0

2020-09

CT#89e

CP-202111

0023

F

Missing error conditions in SMSF registration information retrieval

16.3.0

2020-12

CT#90e

CP-203049

0024

F

Inconsistency between in text and in figure clean up

16.4.0

2020-12

CT#90e

CP-203049

0025

F

SN Deregistration

16.4.0

2020-12

CT#90e

CP-203049

0026

F

UE Reachability for IP

16.4.0

2021-03

CT#91e

CP-210042

0027

F

Removal of SMSF registration notification flag

16.5.0

2021-03

CT#91e

CP-210042

0028

F

P-CSCF Restoration

16.5.0

2021-03

CT#91e

CP-210042

0029

1

F

Cancellation Type sent to MME/SGSN when UE registers in 5G

16.5.0

2021-03

CT#91e

CP-210053

0031

F

Cancellation Type for mobility from EPC to 5GC

16.5.0

2021-06

CT#92e

CP-211053

0032

1

F

Subscription to Changes of SMF Context Data

17.0.0

2022-03

CT#95e

CP-220091

0034

1

F

PDU session continuity

17.1.0

2022-06

CT#96

CP-221063

0038

1

F

Send-Routing-Info-for-SM for retrieval of SMSF Registrations

17.2.0

2022-09

CT#97e

CP-222057

0039

1

F

IMEI Update synchronization

17.3.0

2022-12

CT#98e

CP-223032

0040

1

F

Implicit unsubscribe

18.0.0