Content for TS 23.435 Word version: 19.3.0

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9.16 Slice requirements verification and alignment capability exposure 9.16.1 General 9.16.2 Procedure 9.16.2.1 Procedures on slice requirements verification and alignment capability exposure 9.16.3 Information flows 9.16.4 APIs 9.16.4.1 General 9.16.4.2 SS_NSCE_SliceReq_VerifyAndAlign API 9.16.4.2.1 General 9.16.4.2.2 SliceReq VerifyAndAlign_Subscribe 9.16.4.2.3 SliceReq_VerifyAndAlign_Notification
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9.16 Slice requirements verification and alignment capability exposure p. 102

9.16.1 General p. 102

Verticals can compare the QoS achieved by the provider with the QoS/slice requirements and its own experience of the QoS to verify if the QoS/Slice requirements are reasonably configured. To order a slice with certain slice requirements parameters and their values, the verticals will put their best effort into slice requirements translation. However, they are not able to guarantee that all the potential factors will be considered to generate the optimal slice requirements parameters on the first try.

In some cases, there may be some unforeseen exceptions (e.g., unexpected traffic changes) and the current configured slice requirements parameters are not able to fulfil the verticals requirements (e.g., more resources are required to address the exceptions), the VAL client may also suffer unsatisfied experience. Or in some other cases, when the service is executed on the required slice, the slice may not fully match the service real-time running conditions, for example, maybe only 60% of the slice resource is used to support the service, and rest of the slice resource is always idle, or the slice resource is insufficient due to under-provisioning.

Hence, NSCE is able to provide 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 to check whether the existing QoS/Slice related data is able to satisfy the VAL clients and send periodically alignment notifications to VAL server for the slice requirements. To enable the VAL server to configure the optimal slice requirements parameters to align with the real vertical needs, the NSCE layer is able to monitor the network performance statistics and to evaluate whether the current slice requirements parameters are reasonable to achieve the maximum return of investment. To enable the slice/service self-management, the NSCE server may have the capability to generate and configure more reasonable slice requirements parameters. To avoid frequently reconfiguration of network slice requirements, the action of alignment is triggered by the evaluation of network performance statistics during a certain time period but not by a single event.

9.16.2 Procedure p. 102

9.16.2.1 Procedures on slice requirements verification and alignment capability exposure p. 102

Figure 9.16.2.1-1 provides a possible procedure of slice requirements verification and alignment capability exposure.

Pre-conditions:

The NSCE Server has subscribed to the service of network slice performance management provided by EGMF.

Reproduction of 3GPP TS 23.435, Fig. 9.16.2.1-1: Slice requirements verification and alignment process

Figure 9.16.2.1-1: Slice requirements verification and alignment process

Step 1.

The VAL server sends slice requirements verification and alignment subscription NSCE server to require the NSCE server to check whether the slice requirements (by configuring the attributes of serviceProfile) matches the real network slice usage status, the request may include the S-NSSAI, the ID of the VAL server, the slice requirements parameters (attributes of serviceProfile) which is requested to be aligned. Optionally, the request includes the reporting criteria indicating when the NSCE server needs to send the notification. This alignment reporting allows the VAL server to configure the reporting based on number of UEs, and time information in order to send/block the reporting of alignment notification. The automatic enforcement mode indicates the NSCE server should automatically enforce the updated slice requirement.

Step 2.

The NSCE server checks if the VAL server is authorized to trigger the service of slice requirements alignment.

Step 3.

The NSCE server response to VAL server with the result of slice requirements verification and alignment request, e.g., the slice requirements alignment request is accepted.

Step 4.

The NSCE server may optionally subscribe the QoE data from the NSCE client. The QoE data can refer to the data defined in clause 16 of TS 26.114.

Step 5.

The NSCE server subscribes the network slice related performance data and KPIs (e.g., the average PRB usage, the distribution of the PRB usage) defined in TS 28.552. The NSCE server can aslo subscribe the analytics data (both statistics and predictions) from MDAS and ADAEs.

Step 6a-6b.

NSCE server periodically receives the subscribed data (from steps 4 and 5) and compares the slice requirement parameters of network slice (the values of attributes of serviceProfile, e.g., radioSpectrum, the maxNumberofUEs) with network slice performance statistics (e.g., active number of users, the average PRB usage, the distribution of the PRB usage of the S-NSSAI) to generate the optimal slice requirements for the required service (represented by S-NSSAI) of the vertical.

This step depends on implementation (e.g., if in implementation specific time window the VAL client experience is satisfied while the network slice resources are with low utilization, the resources required in the slice requirements could be reduced based on predictions and statistics). When the reporting criteria is met like generated slice requirement is outside the given slice requirement range, the NSCE server send the notification to inform the VAL about the result of the verification and alignment. If automatic enforcement mode is indicated by the VAL server, the NSCE server enforces the slice optimization with the generated optimal slice requirement as the procedure defined in clause 9.12.2.1.2.

Step 7.

Based on the analysis in step 6, the NSCE server periodically sends notifications to VAL server to inform the recommended changes of the slice requirements parameters. Optionally, if VAL server configures the reporting based on the alignment criteria then the NSCE server reports the notification to the VAL server e.g. based on the mentioned number of UEs are present in the slice, time information.

9.16.3 Information flows p. 104

9.16.3.1 General p. 104

The following information flows are specified for slice requirements verification and alignment capability exposure.

9.16.3.2 Slice requirements verification and alignment subscription p. 104

Table 9.16.3.2-1 describes information elements for slice requirements verification and alignment subscription.

Table 9.16.3.2-1: Slice requirements verification and alignment subscription

Information element	Status	Description
VAL server ID	M	The identifier of the VAL server.
VAL service ID	M	The identifier of the VAL service for which the requirement request applies.
VAL UE ID list	O	The list of VAL UE IDs for which the requirement request applies.
Slice identifier	M	The slice identifier (S-NSSAI, NSI ID or ENSI) which is mapped to the VAL application, if known by the VAL server.
Slice Requirements List	M	The list of the slice requirements which need to be aligned.
> sliceRequirement	M	The requirement which need to be aligned, this parameter refers to the attribute of serviceProfile defined in TS 28.541.
Reporting criteria	O	Indicate the notification reporting criteria, e.g. generated slice requirement is outside the given slice requirement range.
Automatic enforcement mode	O	Indicates the mode for automatic enforcement of the generated optimal slice requirements to meet the slice requirements. E.g OFF or ON.
Alignment reporting criteria	O	Indicates the alignment reporting conditions to the VAL server e.g. based on count of UEs, based on temporal (time information).

9.16.3.3 Response of slice requirements verification and alignment subscription p. 104

Table 9.16.3.3-1 describes information elements for response of slice requirements verification and alignment subscription.

Table 9.16.3.3-1: Response of slice requirements verification and alignment subscription

Information element	Status	Description
Result	M	The result of the subscription (positive or negative acknowledgement).

9.16.3.4 Slice requirements verification and alignment notification p. 104

Table 9.16.3.4-1 describes information elements for slice requirements verification and alignment notification.

Table 9.16.3.4-1: Slice requirements verification and alignment notification

Information element	Status	Description
VAL server ID	M	The identifier of the VAL server.
VAL service ID	M	The identifier of the VAL service for which the requirement request applies.
VAL UE ID list	O	The list of VAL UE IDs for which the requirement request applies.
Slice identifier	M	The slice identifier (S-NSSAI, NSI ID or ENSI) which is mapped to the VAL application, if known by the VAL server.
Updated Slice requirements info	M	The attributes and values of slice requirements.
> Slice requirement alignment enforcement	O	Indicates the updated slice requirement is enforced or not. E.g Yes or No.

9.16.4 APIs p. 105

9.16.4.1 General p. 105

Table 9.16.4.1-1 illustrates the APIs for the network slice verification and alignment capability exposure.

Table 9.16.4.1-1: List of APIs for network slice verification and alignment

API Name	API Operations	Communication Type	Consumer(s)
SS_NSCE_SliceReq_VerifyAndAlign	SliceReq_VerifyAndAlign_Subscribe	Subscription/Notification	VAL server
SS_NSCE_SliceReq_VerifyAndAlign	SliceReq_VerifyAndAlign_Notification	Subscription/Notification	VAL server

9.16.4.2 SS_NSCE_SliceReq_VerifyAndAlign API p. 105

9.16.4.2.1 General p. 105

API description:

This API enables the VAL server to communicate with the network slice capability enablement server to consume the network slice requirements verification and alignment service.