5 Services offered by the PCF

29.5373GPP5G SystemMulticast/Broadcast Policy Control servicesRelease 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.1 Introduction

Table 5.1-1 summarizes the corresponding APIs defined for this specification.

Table 5.1-1: API Descriptions

Service Name	Clause	Description	OpenAPI Specification File	apiName	Annex
Npcf_MBSPolicyControl	5.2	MBS Policy Control Service	TS29537_Npcf_MBSPolicyControl.yaml	npcf-mbspolicycontrol	A.2
Npcf_MBSPolicyAuthorization	5.3	MBS Policy Authorization Service	TS29537_Npcf_MBSPolicyAuthorization.yaml	npcf-mbspolicyauth	A.3

5.2 Npcf_MBSPolicyControl Service

5.2.1 Service Description

The MBS Session Policy Control Service enables the Policy Control Function (PCF) to provision, update and remove MBS session related policies to NF service consumers (e.g. MB-SMF), i.e.:

– enable an NF service consumer to request the creation, update and deletion of an MBS Policy Association for an MBS session; and

– enable the PCF to provision/update/remove MBS policies towards an NF service consumer.

5.2.2 Service Operations

5.2.2.1 Introduction

The service operations defined for the Npcf_MBSPolicyControl Service are shown in table 5.2.2.1-1.

Table 5.2.2.1-1: Npcf_MBSPolicyControl Operations

Service Operation Name	Description	Initiated by
Npcf_MBSPolicyControl_Create	Request the creation of an MBS Policy Association at the PCF in order to receive MBS policies for an MBS session.	NF service consumer (e.g. MB-SMF)
Npcf_MBSPolicyControl_Update	Request the update of an existing MBS Policy Association at the PCF in order to receive the updated MBS policies for an MBS session.	NF service consumer (e.g. MB-SMF)
Npcf_MBSPolicyControl_Delete	Request the deletion of an existing MBS Policy Association.	NF service consumer (e.g. MB-SMF)

5.2.2.2 Npcf_MBSPoliyControl_Create

5.2.2.2.1 General

The Npcf_MBSPolicyControl_Create service operation enables an NF service consumer (e.g. MB-SMF) to request the creation of an MBS Policy Association at the PCF and the provisioning of MBS policies for a multicast or a broadcast MBS session.

The following procedures using the Npcf_MBSPolicyControl_Create service operation are supported:

– MBS Policy Association Establishment.

5.2.2.2.2 MBS Policy Association Establishment

Figure 5.2.2.2.2-1: Procedure for MBS Policy Association establishment

1. In order to request the creation of an MBS Policy Association, the NF service consumer (e.g. MB-SMF) shall send an HTTP POST request to the PCF, as described in step 1of figure 5.2.2.2.2-1, with the request body containing the MbsPolicyCtxtData data structure that shall contain:

– the identifier of the concerned MBS Session, within the "mbsSessionId" attribute;

– the MBS Service Information, within the "mbsServInfo" attribute, if available; and

– the list of supported features, if feature negotiation needs to take place, within the "suppFeat" attribute;

and may contain:

– the DNN of the MBS session, within the "dnn" attribute; and

– the S-NSSAI of the MBS session, within the "snssai" attribute.

2. Upon reception of the HTTP POST request from the NF service consumer:

– if MBS Service Information is present within the "mbsServInfo" attribute, then:

– if the MBS Session being established relates to a location dependent MBS Session and if the PCF is not already serving the MBS Session, the PCF may interact with the BSF by invoking the Nbsf_Management_Register service operation, as specified in clause 4.2.2.4 of 3GPP TS 29.521 [21], to check whether there is already a PCF serving the MBS Session;

NOTE 1: Check whether there is already a PCF serving the MBS Session is not necessary in a deployment with a single PCF.

– if there is a PCF already serving the MBS Session, the PCF shall respond to the NF service consumer with an HTTP "308 Permanent Redirection" status code including an HTTP Location header field containing the "apiRoot" (e.g. FQDN or IP address) of the PCF currently serving the MBS Session;

– otherwise:

– the PCF may interact with the UDR to retrieve MBS policy authorization information for the MBS session, as specified in 3GPP TS 29.519 [20]; and

– the PCF shall perform MBS policy authorization based on the received MBS Service Information, and the operator policies that are pre-configured at the PCF and/or the MBS Session policy control data retrieved from the UDR;

– if MBS policy authorization is successful, the PCF shall derive the required MBS policies (e.g. QoS parameters) and determine whether they are allowed or not;

– if the required MBS policies are allowed:

– the PCF shall store the generated MBS policies for the MBS session together with the corresponding MBS session ID; and

– if MBS policy authorization is not successful or the required MBS policies are not allowed, the PCF shall reject the request with an appropriate error response as specified below in this clause;

NOTE 2: If MBS Service Information is not present in the received request, then the PCF has previously determined and generated the required MBS policies for the MBS session as specified in clause 5.3.

– upon success, the PCF shall:

– create a new "Individual MBS Policy" resource; and

– respond to the NF service consumer with an HTTP "201 Created" status code including a Location header field containing the URI of the created "Individual MBS Policy" resource, and the response body including the MbsPolicyData data structure that shall contain:

– the received input parameters within the request body, within the "mbsPolicyCtxtData" attribute;

– the provisioned MBS Policy Decision, within the "mbsPolicies" attribute; and

– the list of supported features, if feature negotiation is taking place, within the "suppFeat" attribute;

– if errors occur when processing the HTTP POST request, the PCF shall apply the error handling procedures specified in clause 6.1.7;

– if MBS Service Information is provided, but it is invalid, incorrect or insufficient for the PCF to perform MBS policy authorization, the PCF shall reject the request with an HTTP "400 Bad Request" response message including the the ProblemDetails data structure with the "cause" attribute set to "INVALID_MBS_SERVICE_INFO";

– if MBS Service Information is provided, but the MBS IP flow(s) description provided within the MBS Service Information cannot be handled by the PCF because the restrictions defined in clause 5.3.8 of 3GPP TS 29.214 [19] are not respected, the PCF shall reject the request with an HTTP "400 Bad Request" status code including the ProblemDetails data structure with the "cause" attribute set to "FILTER_RESTRICTIONS_NOT_RESPECTED";

– if from an application level point of view, the provided set of input parameters is incomplete, erroneous or missing necessary information for the PCF to perform MBS policy control, the PCF shall reject the request with an HTTP "400 Bad Request" response message including the ProblemDetails data structure with the "cause" attribute set to "ERROR_INPUT_PARAMETERS";

– if MBS Service Information is provided, but it is not authorized, the PCF shall reject the request with an HTTP "403 Forbidden" status code including the MbsExtProblemDetails data structure that shall contain:

– the ProblemDetails data structure with the "cause" attribute set to "MBS_SERVICE_INFO_NOT_AUTHORIZED";

and may contain:

– the AcceptableMbsServInfo data structure including the MBS Service Information that is acceptable for the PCF;

and

– if the PCF denies the creation of the "Individual MBS Policy" resource based on local configuration and/or operator policies, the PCF shall reject the request within an HTTP "403 Forbidden" status code including the "cause" attribute of the ProblemDetails data structure set to "MBS_POLICY_CONTEXT_DENIED". At the reception of this error code and based on the internally configured failure actions, the NF service consumer may reject or allow, by applying local policies, the establishment of the corresponding MBS session.

5.2.2.3 Npcf_MBSPolicyControl_Update

5.2.2.3.1 General

The Npcf_MBSPolicyControl_Update service operation enables the NF service consumer (e.g. MB-SMF) to request the update of an existing "Individual MBS Policy" resource for a multicast or a broadcast MBS session and/or report MBS Policy Decision installation and/or enforcement failure(s) to the PCF.

The following procedures using the Npcf_MBSPolicyControl_Update service operation are supported:

– MBS Policy Association Update.

5.2.2.3.2 MBS Policy Association Update

Figure 5.2.2.3.2-1: Procedure for MBS Policy Association Update

1. In order to request the update of an existing MBS Policy Association, the NF service consumer shall invoke the "Update" resource custom operation URI by sending an HTTP POST request targeting the URI of the corresponding "Individual MBS Policy" resource custom operation, i.e. "{apiRoot}/npcf-mbspolicycontrol/<apiVersion>/mbs-policies/{mbsPolicyId}/update", with the request body including the MbsPolicyCtxtDataUpdate data structure that may contain:

– the updated MBS Service Information, within the "mbsServInfo" attribute;

– the MBS Policy Control Request Triggers that are met, within the "mbsPcrts" attribute, and/or

– the MBS Error reporting containing the MBS Policy Decision installation and/or enforcement failure(s), within the "mbsErrorReport" attribute.

2. Upon reception of the HTTP POST request from the NF service consumer:

– if the "MBS_SESSION_UPDATE" is triggered and updated MBS Service Information is present within the "mbsServInfo" attribute, then the PCF shall perform MBS policy authorization for the received updated MBS Service Information, taking into account the operator policies that are pre-configured at the PCF and/or the MBS Session policy control data retrieved from the UDR;

– if MBS policy authorization is not successful or the required MBS policies are not allowed, the PCF shall reject the request with an appropriate error response as specified below in this clause;

– if MBS policy authorization is successful, the PCF shall derive the required updated MBS policies (e.g. QoS parameters), if any, and determine whether they are allowed or not;

– if the required updated MBS policies are allowed, the PCF shall store the generated updated MBS policies for the MBS session together with the corresponding MBS session ID; and

– if the "MBS_SESSION_UPDATE" is triggered and no updated MBS Service Information is provided, then the PCF may identify whether there is any updated MBS policies that need to be applied based on local configuration;

NOTE: If updated MBS Service Information is not present in the received request, then the PCF has previously determined and generated the required updated MBS policies for the MBS session as specified in clause 5.3.

– if MBS Policy Decision installation and/or enforcement failure(s) reporting is present in the request, the PCF may take it into account when deriving the required updated MBS policies as specified in clause 5.2.4.1;

– upon success, the PCF shall:

– update the corresponding "Individual MBS Policy" resource accordingly; and

– respond to the NF service consumer with an HTTP "200 OK" status code with the response body including the MbsPolicyData data structure that shall contain:

– the updated complete list of input parameters, within the "mbsPolicyCtxtData" attribute;

and may contain:

– the updated MBS Policy Decision containing the updated, deleted and/or newly provisioned MBS policies, within the "mbsPolicies" attribute;

– if errors occur when processing the HTTP POST request, the PCF shall apply the error handling procedures specified in clause 6.1.7;

– if updated MBS Service Information is provided, but it is invalid, incorrect or insufficient for the PCF to perform MBS policy authorization, the PCF shall reject the request with an HTTP "400 Bad Request" response message including the the ProblemDetails data structure with the "cause" attribute set to "INVALID_MBS_SERVICE_INFO";

– if updated MBS Service Information is provided, but the MBS IP flow(s) description provided within the MBS Service Information cannot be handled by the PCF because the restrictions defined in clause 5.3.8 of 3GPP TS 29.214 [19] are not respected, the PCF shall reject the request with an HTTP "400 Bad Request" status code including the ProblemDetails data structure with the "cause" attribute set to "FILTER_RESTRICTIONS_NOT_RESPECTED";

– if updated MBS Service Information is provided, but it is not authorized, the PCF shall reject the request with an HTTP "403 Forbidden" status code including the MbsExtProblemDetails data structure that shall contain:

– the ProblemDetails data structure with the "cause" attribute set to "MBS_SERVICE_INFO_NOT_AUTHORIZED";

and may contain:

– the AcceptableMbsServInfo data structure including the MBS Service Information that is acceptable for the PCF;

– if the PCF denies the update of the "Individual MBS Policy" resource based on local configuration and/or operator policies, the PCF shall reject the request within an HTTP "403 Forbidden" status code including the ProblemDetails data structure with the "cause" attribute set to "MBS_POLICY_CONTEXT_DENIED". At the reception of this error code and based on the internally configured failure actions, the NF service consumer (MB-SMF) may reject or allow, by applying local policies, the establishment of the corresponding MBS session; and

– if the targeted "Individual MBS Policy" resource does not exist, the PCF shall reject the request with an HTTP "404 Not Found" status code including the ProblemDetails data structure with the "cause" attribute set to "MBS_POLICY_ASSOCIATION_NOT_FOUND".

5.2.2.4 Npcf_MBSPolicyControl_Delete

5.2.2.4.1 General

The Npcf_MBSPolicyControl_Delete service operation enables the NF service consumer (e.g. MB-SMF) to request the deletion of an existing "Individual MBS Policy" resource.

The following procedures using the Npcf_MBSPolicyControl_Delete service operation are supported:

– MBS Policy Association Deletion.

5.2.2.4.2 MBS Policy Association Deletion

Figure 5.2.2.4.2-1: MBS Policy Association Deletion procedure

1. In order to request the deletion of an existing MBS Policy Association, the NF service consumer shall send an HTTP DELETE request targeting the URI of the corresponding "Individual MBS Policy" resource.

2. On successful deletion of the MBS Policy Association:

– the PCF may deregister at the BSF from being the PCF serving the MBS Session, if the PCF created such MBS Session binding during the creation of the MBS Policy Association, as specified in clause 5.2.2.2; and

– the PCF shall respond to the NF service consumer (MB-SMF) with an HTTP "204 No Content" status code.

If errors occur when processing the HTTP DELETE request, the PCF shall apply the error handling procedures specified in clause 6.1.7.

If the targeted "Individual MBS Policy" resource does not exist, the PCF shall reject the request with an HTTP "404 Not Found" status code including the ProblemDetails data structure with the "cause" attribute set to "MBS_POLICY_ASSOCIATION_NOT_FOUND".

5.2.3 MBS Policy Decision Management

5.2.3.1 General

An MBS Policy Decision enables to provide the necessary MBS policies for controlling an MBS Session. An MBS Policy Decision is encoded via the MbsPolicyDecision data structure defined in clause 6.1.6.2.3 and composed of the following information:

– MBS PCC rule(s), within the "mbsPccRules" attribute.

– MBS QoS decision(s), which can be referred by MBS PCC rules, within the "mbsQosDecs" attribute.

– Set(s) of MBS QoS characteristics for non-standardized and non-preconfigured 5QIs, within the "mbsQosChars" attribute.

– The authorized MBS Session-AMBR, within the "authMbsSessAmbr" attribute.

– The MBS Policy Control Request Trigger(s), within the "mbsPcrts" attribute.

The following clauses describe the above components of an MBS Policy Decision.

5.2.3.1.1 MBS PCC Rule definition

An MBS PCC rule enables to provide MBS policy control for an MBS service data flow. It is composed of the following information, as defined in table 5.2.3.1.1-1.

– Information enabling the detection of the MBS service data flow.

– A set of MBS Policy Control parameters to be enforced for the MBS service data flow.

Table 5.2.3.1.1-1: Content of an MBS PCC rule

Name	Description	Category
MBS PCC Rule identifier	Uniquely identifies the MBS PCC rule, within an MBS Session. It is used between the PCF and the MB-SMF for referencing MBS PCC rules of an MBS Session.	Mandatory
	MBS Service data flow detection
Precedence	Determines the order in which the MBS service data flow template of the MBS PCC rule is applied relative to the MBS service data flow templates of the other MBS PCC rules of the MBS session, during MBS service data flow detection and policy enforcement.	Mandatory
MBS Service Data Flow Template	The list of MBS service data flow filter(s) for the detection of the MBS service data flow.	Mandatory
	MBS Policy control parameters
5QI	Identifier of the authorized set of QoS parameters for the MBS service data flow.	Mandatory
ARP	The authorized Allocation and Retention Priority for the MBS service data flow, consisting of the priority level, the pre-emption capability and the pre-emption vulnerability.	Mandatory
MBR – Maximum BitRate (DL)	The downlink maximum bitrate authorized for the MBS service data flow.	Optional
GBR – Guaranteed BitRate (DL)	The downlink guaranteed bitrate authorized for the MBS service data flow.	Optional
Averaging Window	Represents the duration over which the guaranteed and maximum bitrates shall be calculated.	Optional
Priority Level	Indicates the level of priority in scheduling resources among MBS QoS flows.	Optional
Maximum Data Burst Volume	Denotes the largest amount of data that is required to be transferred within a period of 5G-AN PDB.	Optional

An MBS PCC rule is encoded via the MbsPccRule data structure defined in clause 6.1.6.2.7 and is composed of the following information:

– An MBS PCC rule identifier that uniquely identifies it within the related MBS Session, within the "mbsPccRuleId" attribute.

– The MBS service data flow template for MBS service data flow detection, within the "mbsDlIpFlowInfo" attribute.

– The precedence information, i.e. the order in which the MBS service data flow template of the MBS PCC rule is applied relative to the MBS service data flow templates of the other MBS PCC rules of the MBS session, during MBS service data flow detection and policy enforcement, within the "precedence" attribute.

– The MBS authorized QoS to be applied for the MBS service data flow corresponding to the MBS PCC rule, i.e. a reference to an MBS QoS decision instance provisioned by the PCF at MBS Policy Decision level, within the "refMbsQosDec" attribute.

The following operations are allowed on MBS PCC rule(s):

– Installation: to provision MBS PCC rule(s).

– Modification: to modify MBS PCC rule(s).

– Removal: to remove MBS PCC rule(s).

5.2.3.1.2 MBS QoS Decision

A Policy Decision based on MBS QoS contains the QoS parameters to be applied for an MBS service data flow. It defines the QoS parameters (e.g. 5QI, ARP, maximum/guaranteed bitrates, etc.) to be applied for the corresponding MBS PCC rule. An MBS QoS decision is encoded via the MbsQosDec data structure defined in clause 6.1.6.2.8 and composed of the following information:

– An identifier of the MBS QoS Decision that uniquely identifies it within the related MBS Session, within the "mbsQosId" attribute.

– The 5QI information, i.e. an identifier of the set of QoS parameters to be applied for an MBS service data flow, within the "5qi" attribute;

– The 5QI Priority Level, within the "priorityLevel" attribute.

– The Allocation and Retention Priority information to be applied for an MBS service data flow, within the "arp" attribute.

– The Maximum Downlink Bit Rate for to be applied for an MBS service data flow, within the "mbrDl" attribute.

– The Guaranteed Downlink Bit Rate to be applied for an MBS service data flow, within the "gbrDl" attribute.

– The averaging window, i.e. the duration over which the guaranteed and maximum bitrates shall be calculated, within the "averWindow" attribute.

– The MBS Maximum Data Burst Volume to be applied for an MBS service data flow, within the "mbsMaxDataBurstVol" attribute.

5.2.3.1.3 MBS QoS Characteristics

A set of MBS QoS Characteristics contains the QoS parameters for a non-standardized and non-preconfigured 5QI. It defines the QoS parameters (e.g. 5QI, ARP, maximum/guaranteed bitrates, etc.) to be applied for an MBS PCC rule and the corresponding MBS service data flow. A set of MBS QoS Characteristics is encoded via the MbsQosChars data structure defined in clause 6.1.6.2.9 and composed of the following information:

– The 5QI information, i.e. an identifier of the set of non-standardized and non-preconfigured QoS parameters for an MBS service data flow. Applies to MBS PCC rule and MBS session level, within the "5qi" attribute.

– The resource type (i.e. GBR, delay critical GBR or non-GBR), within the "resourceType" attribute.

– The 5QI priority level, within the "priorityLevel" attribute.

– The Packet Delay Budget, within the "packetDelayBudget" attribute.

– The Packet Error Rate, within the "packetErrorRate" attribute.

– The averaging window, within the "averWindow" attribute.

– The MBS Maximum Data Burst Volume, within the "mbsMaxDataBurstVol" attribute.

5.2.3.1.4 MBS Session-AMBR

The MBS Session-AMBR contains the Aggregated Maximum Bit Rate to be applied for an MBS session.

5.2.3.1.5 MBS Policy Control Request Triggers

The MBS Policy Control Request Triggers identify the conditions based on which the NF service consumer (MB-SMF) shall trigger the MBS Policy Association Update procedure defined in clause 5.2.2.3. They can be either pre-configured at the NF service consumer (MB-SMF), i.e. implicitly subscribed by default by the PCF, or explicitly provisioned by the PCF to the NF service consumer (MB-SMF) during the MBS Policy Association Creation/Update procedures defined in clause 5.2.2.

The MBS Policy Control Request Triggers are encoded using the MbsPcrt Enumeration data type defined in clause 6.1.6.3.3. The possible values are the following:

– "MBS_SESSION_UPDATE", i.e. MBS Session Update: the MBS policies may need to be updated due to updated MBS Session information. This MBS Policy Control Request Trigger is pre-configured at the NF service consumer (MB-SMF), i.e. implicitly subscribed by the PCF.

5.2.3.2 Provisioning and enforcement of MBS Policy Decisions

5.2.3.2.1 General

MBS Policy Decisions are provided by the PCF to the NF service consumer (MB-SMF) as part of the following service operations:

– the Npcf_MBSPolicyControl_Create service operation defined in clause 5.2.2.2; and

– the Npcf_MBSPolicyControl_Update service operation defined in clause 5.2.2.3.

For the Npcf_MbsPolicyControl_Create service operation, the MbsPolicyDecision data structure shall contain the MBS Policy Decision containing a full description of all the MBS policies provisioned by the PCF for the MBS Policy Association.

For the Npcf_MBSPolicyControl_Update service operation for, the MbsPolicyDecision data structure shall contain the updated MBS Policy Decision containing a full description of all the updated MBS policies provisioned for the MBS Policy Association.

5.2.3.2.2 Provisioning and enforcement of MBS PCC rules

The PCF provisions/updates/removes MBS PCC rule(s) via the "mbsPccRules" map attribute of the MbsPolicyDecision data structure as part of the provisioning/update/removal of an MBS Policy Decision (cf. clause 5.2.3.2.1).

– For provisioning or modifying a dynamic PCF-provisioned MBS PCC rule, the corresponding MbsPccRule data structure shall be provided within the map entry value of the "mbsPccRules" attribute within the MbsPolicyDecision data structure representing the related MBS Policy Decision. The map key shall be set to the value of "mbsPccRuleId" attribute of the MbsPccRule data structure.

– For removing a previously provisioned MBS PCC rule, the corresponding map entry value shall be set to "NULL" and map key to the value of the "mbsPccRuleId" attribute of the MbsPccRule data structure representing the targeted MBS PCC rule.

5.2.3.2.3 Provisioning and enforcement of authorized MBS QoS for an MBS service data flow

The authorized MBS QoS for an MBS service data flow is provisioned along with the corresponding MBS PCC rule, as specified in the clause 5.2.3.2.2.

The MBS authorized QoS per MBS service data flow shall be provisioned within the MbsQosDec data structure representing the MBS QoS Decision to be applied for the MBS service data flow. For this purpose:

– the PCF shall include this MBS QoS Decision instance as a map entry within the "mbsQosDecs" attribute of the MbsPolicyDecision data structure of the corresponding MBS Policy Decision, as specified in clause 5.2.3.1.2, and include the reference to this MBS QoS Decision instance within the "refMbsQosDec" attribute of the MbsPccRule data structure representing the corresponding MBS PCC rule;

– when the PCF provisions a standardized 5QI value, but the Priority Level, the Averaging Window and/or the Maximum Data Burst Volume shall be different from the standardized values defined in the table 5.7.4-1 of 3GPP TS 23.501 [2], the PCF shall include within the corresponding MbsQosDec data structure the required Priority Level within the "priorityLevel" attribute, the Averaging Window within the "averWindow" attribute and/or the MBS Maximum Data Burst Volume within the "mbsMaxDataBurstVol" attribute;

– if the PCF needs to provision dynamically assigned 5QI value(s) (from the non-standardized and non-preconfigured value range) and the associated set(s) of MBS QoS Characteristics, the PCF shall include within the MbsPolicyDecision data structure representing the related MBS Policy Decision the "mbsQosChars" map attribute containing one or more set(s) of MBS QoS Characteristics, with each one of them encoded within a MbsQosChar data structure as specified in clause 5.2.3.1.3. The PCF shall not update nor remove previously provisioned set(s) of MBS QoS Characteristics during the lifetime of the concerned MBS Policy Association;

– when the PCF provisions a dynamically assigned 5QI value (from the non-standardized and non-preconfigured value range) for the MBS PCC rule within the referred MBS QoS Decision instance, then the "5qi" attribute of the corresponding MbsQosDec data structure shall be set to the value of the dynamically assigned 5QI which points to the MBS QoS Characteristics instance containing the related QoS parameters;

NOTE: Operator configuration is assumed to ensure that a dynamically assigned 5QI value is unique and references the same set of MBS QoS characteristics within the whole PLMN at a given time.

Upon reception of an MBS PCC rule provisioning including the corresponding authorized MBS QoS information from the PCF, the NF service consumer (MB-SMF) shall perform MBS QoS flow binding as specified in clause 6.10 of 3GPP TS 23.247 [14]. The NF service consumer (MB-SMF) shall also reserve the necessary resources for the guaranteed bitrate of the MBS PCC rule, if provided. For GBR MBS QoS flows, the NF service consumer (MB-SMF) should set the MBS QoS flow’s GBR to the sum of the GBR(s) of all the MBS PCC rule(s) that are active/installed and bound to that GBR MBS QoS flow, and the MBS QoS flow’s MBR to the sum of the MBR(s) of all the MBS PCC rule(s) that are active/installed and bound to that GBR MBS QoS flow.

The NF service consumer (MB-SMF) shall assign a QFI if a new MBS QoS flow needs to be established and derive the MBS QoS profile required towards the Access Network, if applicable, and the MBS QoS information with PDRs towards the MB-UPF.

During an MBS session policy association update procedure that is updating all the MBS PCC rule(s) bound to a certain MBS QoS flow, if all these MBS PCC rule(s) are updated with the same values of the QoS parameters (e.g. 5QI, ARP, Priority level, Averaging Window and Maximum Data Burst Volume), the NF service consumer (MB-SMF) should not perform a new MBS QoS flow binding and simply modify this MBS QoS flow with the updated QoS parameters.

5.2.3.2.4 Provisioning and enforcement of authorized MBS Session-AMBR

The Provisioning of the authorized MBS Session-AMBR for an MBS session is part of the provisioning of the corresponding MBS Policy Decision, as specified in the clause 5.2.3.2.1.

Upon reception of the authorized MBS Session-AMBR from the PCF, the NF service consumer (MB-SMF) shall trigger the necessary procedures towards the MB-UPF for the provisioning and enforcement of the MBS Session-AMBR for the concerned MBS session.

NOTE: For an MBS session, the authorized MBS Session-AMBR is not propagated to the access network or the UE.

5.2.3.2.5 Provisioning and enforcement of MBS Policy Control Request Triggers

The PCF may provision one or more MBS Policy Control Request Triggers(s) to the NF service consumer (MB-SMF). In order to do so, the PCF shall include the "mbsPcrts" attribute containing one or more MBS Policy Control Request Triggers(s) within the MbsPolicyDecision data structure.

During the lifetime of the MBS Policy Association, the PCF may update and/or remove previously provisioned MBS Policy Control Request Triggers(s):

– In order to update a previously subscribed set of MBS Policy Control Request Triggers(s), the PCF shall provide the complete list of the subscribed MBS Policy Control Request Triggers(s) within the "mbsPcrts" attribute of the MbsPolicyDecision data structure.

– In order to remove all the previously subscribed MBS Policy Control Request Triggers(s), the PCF shall provide the "mbsPcrts" attribute set to the value "NULL" within the MbsPolicyDecision data structure. Upon reception of a "NULL" value within the "mbsPcrts" attribute, the NF service consumer (MB-SMF) shall only trigger the MBS Policy Association Update procedure for the pre-configured MBS Policy Control Request Triggers(s), i.e. the ones implicitly subscribed by the PCF.

MBS Policy Control Request Triggers(s) may also be pre-configured at the NF service consumer as specified in clause 5.2.3.1.5. In such case, the PCF is implicitly subscribed and does not need to explicitly subscribe to these MBS Policy Control Request Triggers(s) towards the NF service consumer (MB-SMF). A combination of pre-configured MBS Policy Control Request Triggers(s) and explicitly subscribed MBS Policy Control Request Triggers(s) may be present for an MBS Policy Association.

5.2.4 MBS Policy Error Handling

5.2.4.1 MBS Report

Following an MBS Policy Association Creation or Update procedure defined in clause 5.2.2.2.2 or 5.2.2.3.2, the NF service consumer (MB-SMF) may report the potentially encountered failure(s) during the installation and/or enforcement of the provisioned MBS Policy Decision, both for MBS Policy Decision level failure(s) (e.g. MBS QoS Decision failure) and MBS PCC rule level failure(s) (e.g. the installation of one or more MBS PCC rule(s) fails or the PCF installed or modified one or more MBS PCC rules but resource allocation for these MBS PCC rule(s) was unsuccessful).

In order to do so, the NF service consumer (MB-SMF) shall trigger the MBS Policy Association Update procedure defined in clause 5.2.2.3.2 and include within the "mbsErrorReport" attribute of the MbsPolicyCtxtDataUpdate data structure the necessary information on the failure(s) that occurred within one or more MBS Report instance(s), each one of them encoded using the MbsReport data structure that shall include:

– the failure reason, if available, within the "failureCode" attribute;

– the affected MBS PCC rule(s), if the reported failure is at MBS PCC rule level, within the "mbsPccRuleIds" attribute; and

– the MBS PCC rule status, if the reported failure is at MBS PCC rule level, within the "mbsPccRuleStatus" attribute.

Depending on the value of the "failureCode" attribute, the PCF may decide on the necessary updates to be applied to the MBS Policy Decision, if any, including whether to retain, re-install, modify or remove the existing MBS PCC rule(s), or any other action applies.

For MBS PCC rule level failure(s), the following handling shall apply:

– if the installation of one or more new MBS PCC rule(s) (i.e. MBS PCC rule(s) which were not successfully installed previously) fails, the NF service consumer (MB-SMF) shall set the "mbsPccRuleStatus" attribute to the value "INACTIVE";

– if one or more MBS PCC rule(s) were successfully installed but can no longer be enforced by the NF service consumer (MB-SMF), the MB-SMF shall set the "mbsPccRuleStatus" attribute to "INACTIVE";

NOTE: When the PCF receives the "mbsPccRuleStatus" set to the value "INACTIVE", the PCF does not need to request the MB-SMF to remove the concerned MBS PCC rule(s) within the "mbsPccRuleIds" attribute.

– if the requested modifications to currently active MBS PCC rule(s) fails, the NF service consumer (MB-SMF) shall:

– retain the targeted existing MBS PCC rule(s) active in their current version (i.e. without any modification), unless the failure reason also impacts the current version of these existing MBS PCC rule(s); and

– report the modification failure to the PCF;

and

– the removal of MBS PCC rule(s) shall not fail. The NF service consumer (MB-SMF) shall retain the MBS PCC rule(s) removal request and perform the necessary actions/procedures in the network when it is possible.

5.3 Npcf_MBSPolicyAuthorization Service

5.3.1 Service Description

The MBS Policy Authorization Service enables the Policy Control Function (PCF) to authorize the MBS Service Information provided by an NF service consumer (e.g. AF, NEF, MBSF) and derive the related MBS policies, i.e.:

– enable an NF service consumer (e.g. AF, NEF, MBSF) to request the creation, update or removal of an MBS Application Session Context, based on the provisioning of MBS Service Information; and

– enable the PCF to authorize the provided MBS Service Information and derive the MBS policies related to the targeted MBS session.

5.3.2 Service Operations

5.3.2.1 Introduction

The service operations defined for the Npcf_MBSPolicyAuthorization Service are shown in table 5.3.2.1-1.

Table 5.3.2.1-1: Npcf_MBSPolicyAuthorization Service Operations

Service Operation Name	Description	Initiated by
Npcf_MBSPolicyAuthorization_Create	Request the creation of an MBS Application Session Context at the PCF, to enable MBS policy authorization for the provided MBS Service Information.	NF service consumer (e.g. NEF, MBSF, AF)
Npcf_MBSPolicyAuthorization_Update	Update an existing MBS Application Session Context at the PCF, to enable MBS policy authorization for the updated MBS Service Information.	NF service consumer (e.g. NEF, MBSF, AF)
Npcf_MBSPolicyAuthorization_Delete	Delete an existing MBS Application Session Context at the PCF.	NF service consumer (e.g. NEF, MBSF, AF)

5.3.2.2 Npcf_MBSPoliyAuthorization_Create

5.3.2.2.1 General

The Npcf_MBSPolicyAuthorization_Create service operation enables an NF service consumer (e.g. AF, NEF, MBSF) to request the creation of an MBS Application Session Context at the PCF, for the purpose of requesting MBS policy authorization for a multicast or a broadcast MBS session.

The following procedures using the Npcf_MBSPolicyAuthorization_Create service operation are supported:

– MBS Application Session Context Establishment.

5.3.2.2.2 MBS Application Session Context Establishment

Figure 5.3.2.2.2-1: MBS Application Session Context establishment procedure

1. In order to request the creation of a new MBS Application Session Context, the NF service consumer (e.g. AF, NEF, MBSF) shall send an HTTP POST request to the PCF, as described in step 1 of figure 5.3.2.2.2-1, targeting the "MBS Application Session Contexts" collection resource, with the request body containing the MbsAppSessionCtxt data structure that shall contain:

– the MBS session identifier, within the "mbsSessionId" attribute;

– the MBS Service Information, if available, within the "mbsServInfo" attribute;

– the list of supported features, if feature negotiation needs to take place, within the "suppFeat" attribute;

and may contain:

– the DNN of the MBS session, within the "dnn" attribute; and

– the S-NSSAI of the MBS session, within the "snssai" attribute.

2. Upon reception of the HTTP POST request from the NF service consumer, the PCF may interact with the UDR to retrieve MBS policy authorization information for the MBS session, as specified in 3GPP TS 29.519 [20]. The PCF shall perform MBS policy authorization based on the MBS Service Information received from the NF service consumer, and the operator policies that are pre-configured at the PCF and/or the MBS Session policy control data retrieved from the UDR. Then:

– if MBS policy authorization is successful, the PCF shall derive the required MBS policies (e.g. QoS parameters) and determine whether they are allowed or not;

– If the required MBS policies are allowed:

– the PCF shall store the generated MBS policies for the MBS session together with the corresponding MBS session ID;

– the PCF shall create a new "Individual MBS Application Session Context" resource and respond to the NF service consumer with an HTTP "201 Created" status code, including an HTTP Location header field containing the URI of the created "Individual MBS Application Session Context" resource and the response body containing a representation of the created resource within the MbsAppSessionCtxt data structure; and

– the PCF may register itself at the BSF as the PCF handling the MBS session as specified in 3GPP TS 29.521 [21];

NOTE: Registering at the BSF as the PCF serving the MBS Session is not necessary in a deployment with a single PCF.

– If MBS policy authorization is not successful or the required MBS policies are not allowed, the PCF shall reject the request with an appropriate error response as specified below in this clause;

– if errors occur when processing the HTTP POST request, the PCF shall apply the error handling procedures specified in clause 6.2.7;

– if the provided MBS Service Information is invalid, incorrect or insufficient for the PCF to perform MBS policy authorization, the PCF shall reject the request with an HTTP "400 Bad Request" status code including the ProblemDetails data structure with the "cause" attribute set to "INVALID_MBS_SERVICE_INFO";

– if the MBS IP flow(s) description provided within the MBS Service Information cannot be handled by the PCF because the restrictions defined in clause 5.3.8 of 3GPP TS 29.214 [19] are not respected, the PCF shall reject the request with an HTTP "400 Bad Request" status code including the ProblemDetails data structure with the "cause" attribute set to "FILTER_RESTRICTIONS_NOT_RESPECTED"; and

– if the provided MBS Service Information are not authorized, the PCF shall reject the request with an HTTP "403 Forbidden" status code including the MbsExtProblemDetails data structure that shall contain:

– the ProblemDetails data structure with the "cause" attribute set to "MBS_SERVICE_INFO_NOT_AUTHORIZED";

and may contain:

– the AcceptableMbsServInfo data structure including the MBS Service Information that is acceptable for the PCF.

5.3.2.3 Npcf_MBSPoliyAuthorization_Update

5.3.2.3.1 General

The Npcf_MBSPolicyAuthorization_Update service operation enables an NF service consumer (e.g. AF, NEF, MBSF) to request the update of an existing MBS Application Session Context, for the purpose of requesting the authorization of updated MBS Service Information.

The following procedures using the Npcf_MBSPolicyAuthorization_Update service operation are supported:

– MBS Application Session Context Update.

5.3.2.3.2 MBS Application Session Context Update

Figure 5.3.2.3.2-1: MBS Application Session Context update procedure

1. In order to request the modification of an existing MBS Application Session Context, the NF service consumer (e.g. AF, NEF, MBSF) shall send an HTTP PATCH request to the PCF targeting the URI of the corresponding "Individual MBS Application Session Context" resource, with the request body containing the MbsAppSessionCtxtPatch data structure that may contain:

– the requested modifications to the MBS Service Information, within the "mbsServInfo" attribute.

2. Upon reception of the HTTP PATCH request from the NF service consumer, the PCF may interact with the UDR to retrieve MBS policy authorization information for the MBS session, as specified in 3GPP TS 29.519 [20]. The PCF shall perform MBS policy authorization based on the requested modifications to the MBS Service Information received from the NF service consumer, and the operator policies that are pre-configured at the PCF and/or the MBS session policy control data retrieved from the UDR. Then:

– if MBS policy authorization of the requested modifications to the MBS Service Information is successful, the PCF shall derive the required MBS policies (e.g. QoS parameters) and determine whether they are allowed or not;

– If the required MBS policies are allowed:

– the PCF shall store the generated MBS policies for the MBS session together with the corresponding MBS session ID;

– the PCF shall update the associated "Individual MBS Application Session Context" resource accordingly and respond to the NF service consumer with either an HTTP "200 OK" status code with the response body containing a representation of the updated resource within the MbsAppSessionCtxt data structure, or an HTTP "204 No Content" status code; and

– if the authorized MBS policies have been changed, the PCF shall include the "contactPcfInd" attribute of the returned MbsAppSessionCtxt data structure set to true to indicate that the PCF shall be contacted, i.e. to indicate to the NF service consumer (MB-SMF) that it needs to trigger the MBS Policy Association Update procedure, as defined in clause 5.2.2.3, to receive updated MBS policies from the PCF;

– If MBS policy authorization is not successful or the required MBS policies are not allowed, the PCF shall reject the request with an appropriate error response as specified below in this clause;

– if errors occur when processing the HTTP PATCH request, the PCF shall apply the error handling procedures specified in clause 6.2.7;

– if the targeted "Individual MBS Application Session Context" resource does not exist, the PCF shall reject the request with an HTTP "404 Not Found" status code including the ProblemDetails data structure with the "cause" attribute set to "MBS_SESSION_POL_AUTH_CTXT_NOT_FOUND";

– the ProblemDetails data structure with the "cause" attribute set to "MBS_SERVICE_INFO_NOT_AUTHORIZED";

and may contain:

– the AcceptableMbsServInfo data structure including the MBS Service Information that is acceptable for the PCF.

5.3.2.4 Npcf_MBSPoliyAuthorization_Delete

5.3.2.4.1 General

The Npcf_MBSPolicyAuthorization_Delete service operation enables an NF service consumer (e.g. AF, NEF, MBSF) to request the deletion of an existing MBS Application Session Context at the PCF.

The following procedures using the Npcf_MBSPolicyAuthorization_Delete service operation are supported:

– MBS Application Session Context Deletion.

5.3.2.4.2 MBS Application Session Context Deletion

Figure 5.3.2.4.2-1: MBS Application Session Context deletion procedure

1. In order to request the deletion of an existing MBS Application Session Context, the NF service consumer (e.g. AF, NEF, MBSF) shall send an HTTP DELETE request to the PCF targeting the URI of the corresponding "Individual MBS Application Session Context" resource.

2. Upon success, the PCF shall respond with an HTTP "204 No Content" status code.

If errors occur when processing the HTTP DELETE request, the PCF shall apply the error handling procedures specified in clause 6.2.7.

If the targeted Individual MBS Application Session Context does not exist, the PCF shall reject the request with an HTTP "404 Not Found" status code including the ProblemDetails data structure with the "cause" attribute set to "MBS_SESSION_POL_AUTH_CTXT_NOT_FOUND".