5.29.2 5G VN group management

5G System supports management of 5G VN Group identification and membership (i.e. definition of 5G VN group identifiers and membership) and 5G VN Group data (i.e. definition of 5G VN group data). The 5G VN Group management can be configured by a network administrator or can be managed dynamically by AF.

A 5G VN group is characterized by the following:

• 5G VN group identities: External Group ID and Internal Group ID are used to identify the 5G VN group.
• 5G VN group membership: The 5G VN group members are uniquely identified by GPSI. The group as described in clause 5.2.3.3.1 of TS 23.502 [3] is applicable to 5G LAN-type services.
• 5G VN group data. The 5G VN group data may include the following parameters: PDU session type, DNN, S-NSSAI and Application descriptor, the indication that the 5G VN group is associated with 5G VN group communication, Information related with secondary authentication / authorization (e.g. to enable IP address assignment by the DN-AAA), Maximum Group Data Rate, User Plane Security Policy.

The Information related with secondary authentication / authorization corresponds to the procedures described in clause 5.6.6; it allows e.g. the AF to provide DN-AAA server addressing information and possibly to request the SMF to get the UE IP address from the DN-AAA server.

NOTE 1: See TS 33.501 [29] for further description on User Plane Security Policy for 5G VN groups.

In order to support dynamic management of 5G VN Group identification and membership, the NEF exposes a set of services to manage (e.g. add/delete/modify) 5G VN groups and 5G VN members. The NEF also exposes services to dynamically manage 5G VN group data.

An AF can request provisioning of traffic characteristics, QoS parameters and monitoring of QoS parameters for a 5G VN group as described in clause 6.1.3.28 of TS 23.503 [45].

A 5G VN group is identified by the AF using External Group ID. The NEF provides the External Group ID to UDM. The UDM maps the External Group ID to Internal Group ID. For a newly created 5G VN Group, an Internal Group ID is determined by the UDM based on implementation specific means.

NOTE 2: The Internal Group ID determined by UDM has to comply with the format defined in TS 23.003 [19].

The NEF can retrieve the Internal Group ID from UDM via Nudm_SDM_Get service operation (External Group ID, Group Identifier translation).

An External Group ID for a 5G VN group corresponds to a unique set of 5G VN group data parameters.

The 5G VN group configuration is either provided by OA&M or provided by an AF to the NEF.

When configuration is provided by an AF, the procedures described in clause 4.15.6.2 of TS 23.502 [3] apply for storing the 5G VN group identifiers, group membership information and group data in the UDR, as follows:

• The NEF provides the External Group ID, 5G VN group membership information and 5G VN group data to the UDM.
• The UDM updates the Internal Group ID-list of the corresponding UE's subscription data in UDR, if needed.
• The UDM updates the Group Identifier translation in the Group Subscription data with the Internal Group ID, External Group ID and list of group members, if needed.
• The UDM stores/updates the 5G VN group data (PDU session type, DNN and S-NSSAI, Application descriptor, the indication that the 5G VN group is associated with 5G VN group communication, Information related with secondary authentication / authorization, Maximum Group Data Rate, User Plane Security Policy) in UDR.

The DNN, S-NSSAI, User Plane Security Policy provided within 5G VN group data cannot be modified after the initial provisioning, i.e. the Nudm_ParameterProvision_Update and Nudr_DM_Update service operations do not apply for DNN, S-NSSAI, User Plane Security Policy within 5G VN group data.

NOTE 3: It is assumed that all members of a 5G VN group belong to the same UDM Group ID. The NEF can select a UDM instance supporting the UDM Group ID of any of the member GPSIs of the 5G VN group.

NOTE 4: Shared data mechanisms as defined in TS 29.503 [122] can be used to support large 5G VN groups.

An AF may also configure and update the service area, QoS for the 5G VN group as described in clause 5.20b as well as other parameters (e.g. Expected UE Behaviour parameters, Network Configuration parameters, ECS Address Configuration Information, etc.) for a 5G VN group as described in clause 4.15.6 of TS 23.502 [3].

If a UE is member of a 5G VN Group, UDM retrieves UE subscription data and corresponding 5G VN group data from UDR and provides the AMF and SMF with UE subscription data with 5G VN group data included. If the 5G VN group data contains the indication that the 5G VN group is associated with 5G VN group communication, the SMF may apply the 5G VN group communication as defined in clauses 5.29.3 and 5.29.4 for the PDU Sessions accessing to the 5G VN group.

The PCF generates URSP rules based on 5G VN group data. The PCF retrieves 5G VN group data from UDR. The PCF(s) that have subscribed to modifications of 5G VN group data receive(s) a Nudr_DM_Notify notification of 5G VN group data change from the UDR as defined in TS 29.505 [145]. The PCF receives from the AMF at the UE Policy association establishment the Internal Group ID(s) corresponding to a UE, so that PCF identifies the 5G VN group data that needs to be used to generate URSP rules to the UE. If the PCF is made aware of a change of UE Internal Group Identifier(s) as defined in TS 29.525 [144] or change of 5G VN group membership as defined in TS 29.505 [145], or both, the PCF then may update the URSP rules for the impacted 5G VN group members.

NOTE 5: The proper way to obtain the 5G VN group membership changes of a specific UE, e.g. if the UE is added to a new 5G VN group, is via the notification of change of UE Internal Group Identifier(s) from the AMF as specified in TS 29.525 [144]. The subscription in the UDR is for being notified about changes in the 5G VN group data and in the 5G VN group membership of a specific 5G VN group.

If the PCF receives the Maximum Group Data Rate as part of the 5G VN group data, it performs the group related policy control as described in clauses 6.1.5 and 6.2.1.11 of TS 23.503 [45].

An AF may update the UE Identities of the 5G VN group at any time after the initial provisioning.

An AF may subscribe to notification of the group status changes for the 5G VN group as described in clause 5.20.

In this Release of the specification, the home network of the 5G VN group members is same.

In this Release of the specification, only a 1:1 mapping between (DNN, S-NSSAI) combination and 5G VN group is supported.

The PCF delivers 5G VN group configuration information (DNN, S-NSSAI, PDU session type) to the UE for each GPSI that belongs to a 5G VN group. The 5G VN group configuration information is delivered in the URSP from the PCF to the UE using the UE Configuration Update procedure for transparent UE Policy delivery as described in clause 4.2.4.3 of TS 23.502 [3] and clause 6.1.2.2 of TS 23.503 [45].