5 Services offered by the MBSTF

29.5813GPP5G SystemMulticast/Broadcast Service Transport ServicesRelease 17Stage 3TS

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

5.1 Introduction

Table 5.1-1 summarizes the SBI services produced by the MBSTF.

Table 5.1-1: NF Services provided by MBSTF

Service Name	Description	Example Consumers
Nmbstf_MBSDistributionSession	Manage (e.g. Create, Modify, Delete) a new MBS Distribution Session within the MBSTF.	MBSF

Table 5.1-2 summarizes the corresponding APIs defined for this specification.

Table 5.1-2: API Descriptions

Service Name	Clause	Description	OpenAPI Specification File	apiName	Annex
Nmbstf_MBSDistributionSession	5.2	MBSTF Distribution Session Service	TS29581_ Nmbstf_DistSession.yaml	nmbstf-distsession	A.2

5.2 Nmbstf_MBSDistributionSession Service

5.2.1 Service Description

The Nmbstf_MBSDistributionSession service operates on MBS distribution sessions. The following are the key functionalities of this NF service:

– Creation, modification, retrieval and deletion of MBS Distribution Sessions

Table 5.2.1-1 lists the service operations that are supported by the Nmbstf_MBSDistributionSession service.

Table 5.2.1-1: Service operations supported by the Nmbstf_MBSDistributionSession service

Service Operations	Description	Operation Semantics	Example Consumers
Create	Create a new MBS Distribution Session within the MBSTF	Request / Response	MBSF
Update	Update an existing MBS Distribution Session	Request / Response	MBSF
Destroy	Delete an existing MBS Distribution Session	Request / Response	MBSF
Retrieve	Retrieve the parameters of an existing MBS Distribution Session	Request / Response	MBSF
StatusSubscribe	Subscribe to notifications related to an MBS Distribution Session	Subscribe/ Notify	MBSF
StatusUnsubscribe	Unsubscribe from notifications related to an MBS Distribution Session		MBSF
StatusNotify	Notify event(s) related to an MBS Distribution Session		MBSF

5.2.2 Service Operations

5.2.2.1 Introduction

See Table 5.2.1-1 for an overview of the service operations supported by the Nmbstf_MBSDistributionSession service.

5.2.2.2 Create

5.2.2.2.1 General

The Create service operation shall be used to create a new MBS Distribution Session within the MBSTF (see clauses 5.2, 4.5.2 of 3GPP TS 26.502 [17]).

The NF Service Consumer (e.g. MBSF) shall create an MBS Distribution session in the MBSTF by using the HTTP POST method as shown in Figure 5.2.2.2.1-1.

Figure 5.2.2.2.1-1: MBS Distribution session creation

1. The NF Service Consumer shall send a POST request (CreateReqData) targeting the MBS Distribution Sessions collection resource of the MBSTF. The payload body of the POST request shall contain the following information:

– The baseline parameters for an MBS Distribution Session including Distribution Session Identifier; if security protection is applied, the multicast session security context containing MBS Session Key (MSK), MSK lifetime and the corresponding key ID(s), and;

– Additional MBS Distribution Session parameters for Object Distribution Method, or;

– Additional MBS Distribution Session parameters for Packet Distribution Method;

2a. On success, the MBSTF shall return a "201 Created" response. The "Location" header shall be present and shall contain the URI of the created resource. The payload body of the POST response (CreateRspData) shall contain a representation of the created MBS session.

If MBSTF received MBS Session Key (MSK) and the corresponding key IDs in Create request, the response may include the multicast session security context containing MBS Session Key (MSK), MBS Traffic Key (MTK) and the corresponding key IDs,

2b. On failure, one of the HTTP status code listed in Table 6.1.3.2.3.1-3 shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application errors listed in Table 6.1.3.2.3.1-3.

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of POST response.

5.2.2.3 Update

5.2.2.3.1 General

The Update service operation shall be used to update an existing MBS Distribution Session within the MBSTF (see clauses 5.2, 4.5.2 of 3GPP TS 26.502 [17]).

The NF Service Consumer (e.g. MBSF) shall update an MBS Distribution session in the MBSTF by using the HTTP PATCH method as shown in Figure 5.2.2.3.1-1.

Figure 5.2.2.3.1-1: MBS Distribution session update

1. The NF Service Consumer shall send a PATCH request (PatchData) to update the MBS distribution session. The request may include an updated multicast session security context containing MBS Session Key (MSK), MSK lifetime and the corresponding key IDs if MBSF generated a new MSK.

2a. On success, the MBSTF shall return "204 No Content";

2b. On success, the MBSTF shall return "200 OK" containing new resource representation of MBS distribution session, if MBSTF received an updated multicast session security context, and/or if the MBSTF generated a new MBS Traffic Key (MTK);

2c. On failure, one of the HTTP status code listed in Table 6.1.3.3.3.1-3 shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application errors listed in Table 6.1.3.3.3.1-3.

2d. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of PATCH response.

5.2.2.4 Destroy

5.2.2.4.1 General

The Destroy service operation shall be used to delete an existing MBS Distribution Session within the MBSTF (see clauses 5.2, 4.5.2 of 3GPP TS 26.502 [17]).

The NF Service Consumer (e.g. MBSF) shall delete an MBS Distribution session in the MBSTF by using the HTTP DELETE method as shown in Figure 5.2.2.4.1-1.

Figure 5.2.2.4.1-1: MBS Distribution session deletion

1. The NF Service Consumer shall send a DELETE request (distSessionRef) to release the MBS distribution session.

2a. On success, the MBSTF shall delete the MBS distribution session and return a "204 No Content" response.

2b. On failure, one of the HTTP status code listed in Table 6.1.3.3.3.2-3 shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application errors listed in Table 6.1.3.3.3.2-3.

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of DELETE response.

5.2.2.5 Retrieve

5.2.2.5.1 General

The Retrieve service operation shall be used to retrieve the parameters of an existing MBS Distribution Session within the MBSTF (see clauses 5.2, 4.5.2 of 3GPP TS 26.502 [17]).

The NF Service Consumer (e.g. MBSF) shall retrieve an MBS Distribution session in the MBSTF by using the HTTP GET method as shown in Figure 5.2.2.5.1-1.

Figure 5.2.2.5.1-1: MBS Distribution session retrieval

1. The NF Service Consumer shall send a GET request to the resource representing the MBS distribution session (distSessionRef).

2a. On success, the MBSTF shall respond with "200 OK" with the message body containing parameters of the distribution session (distSession).

2b. On failure, one of the HTTP status code listed in Table 6.1.3.3.3.3-3 shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application errors listed in Table 6.1.3.3.3.3-3.

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of GET response.

5.2.2.6 StatusSubscribe service operation

5.2.2.6.1 General

The StatusSubscribe service operation shall be used by an NF Service Consumer (e.g. MBSF) to create a subscription to the MBSTF notifications related to the event(s) of an MBS distribution session.

5.2.2.6.2 Subscription creation

The NF Service Consumer (e.g. MBSF) shall subscribe to MBSTF service notifications by using the HTTP POST method as shown in Figure 5.2.2.6.2-1.

Figure 5.2.2.6.2-1: Subscribing to MBSTF notifications

1. The NF Service Consumer shall send a POST request (StatusSubscribeReqData) to the resource URI representing the subscriptions collection resource in the MBSTF. The payload body of the POST request shall contain:

– the list of MBS distribution session events requested to be subscribed.

– the Notification URI , indicating the address where the MBSTF shall send the notifications;

The request body may also contain:

– an expiry time suggested by the NF Service Consumer, representing the time span during which the subscription is desired to be kept active; and

– Notification Correlation ID;

– the Distribution Session Identifier;

– the list of events successfully subscribed;

– the expiry time after which the subscription becomes invalid.

2b. On failure, one of the HTTP status code listed in the data structures supported by the POST Response Body (see Table 6.1.3.4.3.1-3) shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application error listed in the same Table 6.1.3.4.3.1-3).

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of POST response.

5.2.2.6.3 Subscription update

When the StatusSubscribe service operation is used for updating a subscription, the NF Service Consumer (e.g. MBSF) shall update its subscription to MBSTF notifications by using the HTTP PATCH method as shown in Figure 5.2.2.6.3-1.

Figure 5.2.2.6.3-1: Updating a subscription to MBSTF notifications

1. The NF Service Consumer shall send a PATCH request to update the individual subscription resource in the MBSTF (/dist-sessions/{distSessionRef}/subscriptions/{subscriptionId}). The message body contains an array(PatchItem), where each PatchItem type indicates a requested change to the DistSessionSubscription data structure (see clause 6.1.6.2.10). The following information may be requested to be modified with array(PatchItem) structure (see Table 6.1.3.5.3.2-2):

– Notification URI (callback URI), indicating the address where the MBSTF shall send the notifications;

– New expiration time;

2a. On success, the MBSTF shall return a "200 Ok" response with a representation of the modified subscription (DistSessionSubscription data structure (see clause 6.1.6.2.10)).

2b. On failure, one of the HTTP status code listed in Table 6.1.3.5.3.2-3 shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application errors listed in Table 6.1.3.5.3.2-3.

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of PATCH response.

5.2.2.7 StatusUnsubscribe

5.2.2.7.1 General

The StatusUnsubscribe service operation shall be used by an NF Service Consumer (e.g. MBSF) to unsubscribe from the MBSTF notifications related to an MBS distribution session.

The NF Service Consumer (e.g. MBSF) shall unsubscribe from MBSTF notifications by using the HTTP DELETE method as shown in Figure 5.2.2.7.1-1.

Figure 5.2.2.7.1-1: Unsubscribing from MBSTF notifications

1. The NF Service Consumer shall send a DELETE request to the resource URI representing the individual subscription document resource in the MBSTF.

2. On success, the MBSTF shall return a "204 No Content" response.

2b. On failure, one of the HTTP status code listed in the data structures supported by the DELETE Response Body (see Table 6.1.3.5.3.1-3) shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application error listed in the same Table 6.1.3.5.3.1-3.

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of DELETE response.

5.2.2.8 StatusNotify

5.2.2.8.1 General

The StatusNotify service operation shall be used by the MBSTF to notify a subscribed NF Service Consumer (e.g. MBSF) about the events related to an MBS distribution session.

The MBSTF shall notify the NF Service Consumer (e.g. MBSF) by using the HTTP POST method to the callback URI received earlier in the subscription as shown in Figure 5.2.2.8.1-1.

Figure 5.2.2.8.1-1: MBTSMF notifications

1. The MBSTF shall send a POST request (StatusNotifyReqData) to the callback URI ({notifUri}) of the subscribed NF Service Consumer. The payload body of the POST request shall contain:

– Notification Correlation ID, if this information was provided during subscription;

– the list of MBS distribution session events to be reported:

– report a DATA_INGEST_FAILURE event when the MBSTF failed to ingest data from the AF/AS;

– report a SESSION_DEACTIVATED event when the MBS distribution session is released in the MBSTF;

– report a SESSION_ACTIVATED event when the delivery started toward the MB-UPF.

2a. On success, the MBSF shall return a "204 No Content" response.

2b. On failure, one of the HTTP status code listed in the data structures supported by the POST Response Body (see Table 6.1.5.2.3.1-2) shall be returned. The message body shall contain a ProblemDetails structure with the "cause" attribute set to one of the application error listed in the same Table 6.1.5.2.3.1-2).

2c. On redirection, "307 Temporary Redirect" or "308 Permanent Redirect" shall be returned. A RedirectResponse IE shall be included in the payload body of POST response.