This functionality enables the VAL server to become a recognized user of CAPIF. VAL server registration procedures are specified in clause 9.2.

This functionality is provided to the vertical application specific layer and configures the exposure of APIs in a slice-tailored manner. It is assumed that the VAL server is not initially aware of the all the API exposure capabilities and information which will be needed for the given slice based on the SLA, and NSCE plays a vital role in configuring and translating the slice API based on the per slice requirements to service APIs. Slice API configuration and translation procedures are specified in clause 9.3.

Application layer network slice lifecycle management is provided to the VAL to better meet consumer's requirement without having to interact with 5GS frequently, based on network slice status collected from 5GS and QoE collected from application layer. Application layer network slice lifecycle management procedures are specified in clause 9.4.

Network slice optimization based on VAL server policy optimizes the network slice for the vertical applications by triggering the network slice modification exposed by EGMF defined in SA5. Network slice optimization based on VAL server policy procedures are specified in clause 9.5.

This network slice capability enablement feature supports the initial discovery of MnS for a given slice based on VAL server request, and the discovery of new/modified MnS with the required exposure (for example the permissions of the VAL server over the target MnS, e.g. read, write operations). This feature consists of two procedures, which are specified in clause 9.6:

• Discovery of management service capabilities and related permissions (e.g. permitted CRUD operations) based on VAL server request;
• Discovery and exposure of new or modified management service capabilities based on changes at OAM.

This functionality is provided to the VAL to get end to end network slice related performance and analytic monitoring. The NSCE server identifies which data are needed, collects the data from different data sources (e.g., the OAM system, the 5GC Network, etc.), performs data processing and abstraction, exposes the processed data to VAL servers. Network slice performance and analytics monitoring procedures are specified in clause 9.7.

The network slice status collected by the NSCE server could be exposed to other NSCE server(s) if some agreement has been made. Information collection from NSCE server(s) procedures are specified in clause 9.8.

This feature addresses scenarios where the NSCE server is deployed at the edge and the migration to different Data Network will require that the ongoing slice is supported at the target area to ensure meeting the application session requirements. The slice parameters monitoring at the target area (e.g. for per NSI/NSSI resource situation) need to be known at the server NSCE server to allow for pro-active slice (or slice subnet) modification trigger to avoid degradation of the application service performance. Predictive slice modification procedures are specified in clause 9.9.

This functionality is provided to the VAL to monitor the slice usage status of multiple slices (PNI-NPN slice(s) and its private slice in the PLMN) of the PNI-NPN owner in a combined manner. It makes resource adjustment between different slices in one PLMN to realize optimized and efficient resource usage among multiple slices sharing common network resources. Coordinated PLMN and PNI-NPN slice resource optimization procedures are specified in clause 9.10.

This functionality is provided to the VAL to adapt the network slice for the VAL application. Such adaptation assumes that the UE is subscribed to more than one slice and is done via providing a guidance to update the URSP rules at the 5GS. The network slice adaptation request can be triggered by VAL server or VAL UE. Network slice adaptation for VAL application procedures are specified in clause 9.11.

This functionality is provided to the VAL server to make slice related communication service lifecycle management. The NSCE server can acquire the application services related requirements for a specific VAL service from the vertical industry perspective, evaluate these requirements and then determines the network slice by pre-configured industry mapping relations or by KQI-KPI translation algorithms. After the network slice requirements are determined, the NSCE server allocates proper network slice resources to support the application services. Slice related communication service lifecycle management exposure procedures are specified in clause 9.12.

This functionality is provided to the VAL to make predictive slice modification where NSCE service provider provides its services when connected to two PLMNs and has SLA with them. The NSCE server checks with 5GS (OAM, 5GC) whether the serving slice is available and can offer the same performance at the target PLMN and make slice modification decision if needed. Predictive slice modification in Inter-PLMN based slice service continuity procedures are specified in clause 9.13.

Network slice diagnostics provides possibility for the vertical/ASP using VAL server to receive information about the specific event(s) related to service experience. The vertical/ASP using the VAL server has estimated bad QoE for a mobile user or service - either reported from a mobile user or service or detected by application, can initiate a check with NSCE. The NSCE server can provide Network slice diagnostics details related to the identified event as specified in clause 9.14.

Network slice fault management capability exposure gathers data from different sources (e.g., OAM, VAL server, NSCE client) and provides fault data that characterize the quality of the network connections and services to ensure a quick reaction to identify network connectivity, performance related problems. The Network slice fault management capability exposure is specified in clause 9.15.

Slice requirements verification and alignment capability exposure provides the capability of comparing the QoS achievement status together with the OAM QoS data versus real customer QoS data (e.g., Mean Opinion Score) collected from VAL client by checking whether the existing QoS/Slice related data is able to satisfy the VAL clients. Periodically alignment notifications are sent to VAL server for the slice requirements alignment. The Slice requirements verification and alignment capability exposure is specified in clause 9.16.

The Network Slice information delivery sends the Network Slice information to VAL server and NSCE client. With that information, the VAL server is able to manage the network slice for their service such as preparation, creation, activation and termination (tear-down) of network slice. The Network Slice Information delivery is specified in clause 9.17.

The NSCE server performs the Network Slice allocation operation on behalf of the VAL server if non-trusted 3rd party application (i.e., VAL server) cannot access to the 5GS management system directly. The specific service is specified in clause 9.18.