AA.2 IMS SBA Services

23.2283GPPIP Multimedia Subsystem (IMS)Release 18Stage 2TS

AA.2.1 HSS Services

AA.2.1.1 General

The following table shows the services exposed by an SBI capable HSS.

Table AA.2.1.1-1: IMS Services provided by an SBI capable HSS

Service

Service Operations

Operation Semantics

Example Consumer(s)

imsSubscriber Data

Get

Request/Response

S-CSCF, I-CSCF, AS

Management (_ImsSDM)

Subscribe

Subscribe/Notify

S-CSCF, AS

Unsubscribe

Subscribe/Notify

S-CSCF, AS

Notification

Subscribe/Notify

S-CSCF, AS

Update

Request/Response

AS

imsUE Context

Registration

Request/Response

S-CSCF

Management

DeregistrationNotification

Subscribe/Notify

S-CSCF

(_ImsUECM)

Deregistration

Request/Response

S-CSCF

Authorize

Request/Response

I-CSCF

Update

Request/Response

S-CSCF

RestorationInfoGet

Request/Response

S-CSCF

RestorationInfoUpdate

Request/Response

S-CSCF

ImsUE Authentication

Get

Request/Response

S-CSCF

AA.2.1.2 Nhss_ImsUEContextManagement (ImsUECM) service

AA.2.1.2.1 Nhss_ImsUECM_Registration service operation

Service operation name: Nhss_ImsUECM_Registration

Description: This service operation registers the serving S-CSCF assigned to an IMS User. If authentication is not to be performed, this operation also sets the registration state. The S-CSCF is implicitly subscribed to be notified when it is deregistered in HSS. This notification is done by means of Nhss_ImsUECM_DeregistrationNotification operation.

Inputs, Required: Public Identity, S-CSCF name, Registration Type (e.g. Initial Registration, Unregistered).

Inputs, Optional: Private Identity.

Outputs, Required: Result indication.

Outputs, Optional: List of registered Private Identities sharing the same Public Identity which is being registered, S-CSCF Restoration indication.

AA.2.1.2.2 Nhss_ImsUECM_Deregistration service operation

Service operation name: Nhss_ImsUECM_Deregistration

Description: This service operation deregisters the S-CSCF allocated to a public identity.

Inputs, Required: S-CSCF name, Deregistration Type.

Inputs, Optional: User Identity (Private Identity and/or Public Identity), P-CSCF Restoration indication, Session Priority.

Outputs, Required: Result indication.

Outputs, Optional: None.

AA.2.1.2.3 Nhss_ImsUECM_DeregistrationNotification service operation

Service operation name: Nhss_ImsUECM_DeregistrationNotification

Description: This service operation enables HSS to inform a S-CSCF which has previously registered in HSS of a Public Identity deregistration. This notification corresponds to an implicit subscription.

Inputs, Required: Private Identity, Reason for Deregistration.

Inputs, Optional: Public Identity, Associated Private Identities.

Outputs, Required: Result indication.

Outputs, Optional: Associated Private Identities, Identities with Emergency Registration.

AA.2.1.2.4 Nhss_ImsUECM_Authorize service operation

Service operation name: Nhss_ImsUECM_Authorize

Description: This service operation is used by the I-CSCF to request authorization from HSS for:

– The registration of a Public Identity by a UE in a P‑CSCF network identifier according to the IMS User’s subscription and operator limitations/restrictions.

– The reception of a terminating request based on the user state and IMS user’s subscription (e.g. IMS User’s barring status).

If the IMS User is authorized, the HSS may provide the address of the S-CSCF assigned to the Public Identity if any.

Additionally, this service operation is used to authorize in HSS a S-CSCF reselection (e.g. after I-CSCF detection if a S-CSCF failure).

Inputs, Required: Public Identity, Authorization Type.

Inputs, Optional: Private User Identity, P‑CSCF network identifier.

Outputs, Required: Result indication.

Outputs, Optional: S-CSCF name.

AA.2.1.2.5 Nhss_ImsUECM_Update service operation

Service operation name: Nhss_ImsUECM_Update

Description: This service operation updates the registration state of a Public Identity or Private Identity in HSS i.e. to update the registration state from Not Registered or Unregistered to Registered state.

NOTE: This operation is used by S-CSCF after successful authentication to set the registration state (if not already set).

Inputs, Required: Public Identity, S-CSCF name.

Inputs, Optional: Private Identity.

Outputs, Required: Result indication.

Outputs, Optional: None.

AA.2.1.2.6 Nhss_ImsUECM_RestorationInfoGet service operation

Service operation name: Nhss_ImsUECM_RestorationInfoGet

Description: This service operation is used between the S-CSCF and the HSS to retrieve information from HSS to support the S-CSCF procedures.

Inputs, Required: Public Identity.

Inputs, Optional: Private Identity.

Outputs, Required: Result Indication.

Outputs, Optional: Restoration data.

AA.2.1.2.7 Nhss_ImsUECM_RestorationInfoUpdate service operation

Service operation name: Nhss_ImsUECM_RestorationInfoUpdate

Description: This service operation is used between the S-CSCF and the HSS to update information in HSS to support the S-CSCF Restoration procedures.

Inputs, Required: Private Identity, Public Identity, Restoration data.

Inputs, Optional: None.

Outputs, Required: Result indication.

Outputs, Optional: None.

AA.2.1.3 Nhss_ImsSubscriberDataManagement (ImsSDM) service

AA.2.1.3.1 General

IMS Subscriber data types used in the Nhss_ImsSDM Service are defined in Table AA.2.1.3.1-1 below.

NOTE: IMS Subscriber data is terminology only used in Annex AA. It includes IMS subscription data and other data related to the subscriber, e.g. network functionality entity address, location information or T-ADS information.

Table AA.2.1.3.1-1: IMS Subscriber data types

IMS Subscriber data

Description

Service Profile Data

This may include e.g. service parameters, the S-CSCF allocated to a public identity or the list of S-CSCFs and their capabilities, Application Server address, triggers, information on subscribed media, profile parameters (e.g. barring indicator, etc.) as defined in TS 29.228 [30].

Service Profile Data is consumed by CSCF.

Repository Data

Data that is understood syntactically but not semantically by the HSS (unstructured Data). It is data that an AS may store in the HSS to support its service logic. One example is data that an AS stores in the HSS, using it as a repository.

Service Indication identifies the set of service related transparent data associated to a Public Identity.

Repository Data is consumed by IMS-AS.

Non-Transparent Data

Data that is understood both syntactically and semantically by the HSS e.g. location information. Non-Transparent Data is structured using data references as defined in TS 29.328 [79].

Non-Transparent Data is consumed by IMS-AS.

At least a mandatory key is required for each IMS Subscriber Data Type to identify the corresponding data as defined in Table AA.2.1.3.1-2 below.

Table AA.2.1.3.1-2: IMS Subscriber data types keys

IMS Subscriber Data Types

Data Key

Data Sub Key

Service Profile Data

Public Identity

Repository Data

Public Identity

Service Indication

Non-Transparent Data

See NOTE 1

NOTE 1: TS 29.328 [79] defines the data keys/subkeys required by each data reference.

AA.2.1.3.2 Nhss_ImsSDM_Get service operation

Service operation name: Nhss_ImsSDM_Get

Description: This service operation enables the NF consumer to fetch the service profile data, repository data, and non-transparent data references for an IMS User.

The HSS shall check that the requested NF consumer is authorized to fetch the requested data. In the case that the requested data is Repository data, the HSS may also authorize based on service indication.

Inputs, Required: NF Type, IMS Subscriber data type(s), Key for each IMS Subscriber data type(s).

Inputs, Optional: Application Service Identity.

Outputs, Required: Result indication.

Outputs, Optional: Requested Data.

AA.2.1.3.3 Nhss_ImsSDM_Subscribe service operation

Service operation name: Nhss_ImsSDM_Subscribe

Description: The NF consumer subscribes for updates to requested data. HSS shall check that the requested NF consumer is authorized to subscribe to requested updates.

Inputs, Required: NF Type, IMS Subscriber data type(s), Key for each IMS Subscriber data type(s).

Inputs, Optional: Application Server Identity.

Outputs, Required: When the subscription is accepted: Subscription Correlation ID.

Outputs, Optional: None.

AA.2.1.3.4 Nhss_ImsSDM_Unsubscribe service operation

Service operation name: Nhss_ImsSDM_Unsubscribe

Description: The NF consumer unsubscribes for updates to Requested data.

Inputs, Required: Subscription Correlation ID.

Inputs, Optional: None.

Outputs, Required: Result.

Outputs, Optional: None.

AA.2.1.3.5 Nhss_ImsSDM_Notification service operation

Service operation name: Nhss_ImsSDM_Notification

Description: This service operation enables HSS to notify a NF of any changes to what the NF subscribed to.

Inputs, Required: IMS Subscriber data type(s), Key for each IMS Subscriber data type(s).

Inputs, Optional: None.

Outputs, Required: Result indication.

Outputs, Optional: None.

AA.2.1.3.6 Nhss_ImsSDM_Update service operation

Service operation name: Nhss_ImsSDM_Update

Description: The NF consumer updates HSS subscription data if authorized to do so.

Inputs, Required: NF Type, IMS Subscriber data type(s), Key for each IMS Subscriber data type(s).

Inputs, Optional: Application Service Identity.

Outputs, Required: Result.

Outputs, Optional: None.

AA.2.1.4 Nhss_ImsUEAuthentication service

AA.2.1.4.1 Nhss_ImsUEAuthenticate_Get service operation

Service operation name: Nhss_ImsUEAuthenticate_Get

Description: This service operation is used between the S-CSCF and the HSS to exchange information to support the authentication between the end user and the home IMS network.

Inputs, Required: Private User Identity, Public User Identity, Authentication Data (Authentication Scheme).

Inputs, Optional: Authentication Data (Authentication Context, Authorization Information).

Outputs, Required: Result Indication.

Outputs, Optional: User Identity, Authentication Data (e.g. AV).

AA.2.2 Mapping of Cx and Sh operations and terminology to HSS SBI services

AA.2.2.1 General

This clause gives mappings from Cx and Sh operations to HSS SBI services and service operations.

AA.2.2.2 Mapping of Cx messages to HSS SBI services

The following table defines the mapping between stage 2 Cx messages and HSS SBI services and service operations:

Table AA.2.2.2-1: Cx messages to HSS SBI services and service operations mapping

Cx message

Source

Destination

HSS SBI service operation name

Cx-Query

I-CSCF

HSS

Nhss_ImsUECM_Authorize

Cx-Select-Pull

I-CSCF

HSS

Nhss_ImsSDM_Get (see NOTE 1)

Cx-Put

S-CSCF

HSS

Nhss_ImsUECM_Registration (see NOTE 2)

Nhss_ImsUECM_Deregistration (see NOTE 3)

Nhss_ImsUECM_Update (see NOTE 4)

Nhss_ImsUECM_RestorationInfoUpdate (see NOTE 5)

Cx-Pull

S-CSCF

HSS

Nhss_ImsSDM_Get (see NOTE 6)

Nhss_ImsSDM_Subscribe (see NOTE 6)

Nhss_ImsSDM_Unsubscribe

Nhss_ImsUECM_RestorationInfoGet (see NOTE 7)

Cx-Location-Query

I-CSCF

HSS

Nhss_ImsUECM_Authorize

Nhss_ImsSDM_Get (see NOTE 8)

Cx-AuthDataReq

S-CSCF

HSS

Nhss_ImsUECM_Registration (see NOTE 9)

Nhss_ImsUEAuthenticate_Get

Cx-Deregister

HSS

S-CSCF

Nhss_ImsUECM_DeregistrationNotification

Cx-Update_Subscr_Data

HSS

S-CSCF

Nhss_ImsSDM_Notification

NOTE 1: Corresponds to Cx-Select-Pull for the requests of S-CSCF capabilities from I-CSCF to the HSS.

NOTE 2: Corresponds to Cx-Put for Registration of S-CSCF in HSS during Registration/Re-registration and Unregistered cases.

NOTE 3: Corresponds to Cx-Put for de-registration of S-CSCF in HSS.

NOTE 4: Corresponds to Cx-Put message for updating the registration state of Public Identity in HSS.

NOTE 5: Corresponds to Cx-Put message for storing S-CSCF Restoration data during IMS registration procedures.

NOTE 6: Corresponds to Cx-Pull when S-CSCF needs to fetch and subscribe to notification of changes in IMS User’s Service Profile Data.

NOTE 7: Corresponds to Cx-Pull for retrieval of S-CSCF Restoration data from HSS.

NOTE 8: Corresponds to Cx-Location-Query for the requests of S-CSCF capabilities from I-CSCF to the HSS.

NOTE 9: Corresponds to Cx-Put for the assignment of a S-CSCF during execution of the authentication of the IMS User.

AA.2.2.3 Mapping of Sh messages to HSS SBI services

The following table defines the mapping between stage 2 Sh messages and HSS SBI services and service operations:

Table AA.2.2.3-1: Sh messages to HSS SBI services and service operations mapping

Sh message

Source

Destination

HSS SBI service operation name

Sh-Pull

AS

HSS

Nhss_ImsSDM_Get

Sh-Update

AS

HSS

Nhss_ImsSDM_Update

Sh-Subs-Notif

AS

HSS

Nhss_ImsSDM_Subscribe

Nhss_ImsSDM_Unsubscribe

Nhss_ImsSDM_Get

Sh-Notif

HSS

AS

Nhss_ImsSDM_Notification