Content for TS 26.512 Word version: 17.3.0

4.4 Procedures of the M2d (5GMS Ingest) interface 4.5 Procedures of the M3d interface 4.6 Procedures of the M4d (Media Streaming) interface 4.7 Procedures of the M5 (Media Session Handling) interface 4.7.1 Introduction 4.7.2 Procedures for Service Access Information 4.7.3 Procedures for dynamic policy invocation 4.7.4 Procedures for consumption reporting 4.7.5 Procedures for metrics reporting 4.7.6 Procedures for network assistance 4.8 Procedures of the M6d (UE Media Session Handling) interface 4.9 Procedures of the M7d (UE Media Player) interface 4.10 Procedures of the M8d interface 4.11 Data collection and reporting procedures at reference point R4 4.12 Event Exposure procedures at reference points R5 and R6 4.13 Procedures for downlink media streaming via eMBMS
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4.4 Procedures of the M2d (5GMS Ingest) interface p. 28

No procedures are specified in this release.

4.5 Procedures of the M3d interface p. 28

Interface M3d is internal and no procedures on this interface are specified.

4.6 Procedures of the M4d (Media Streaming) interface p. 28

4.6.1 Procedures for DASH Session p. 28

This procedure is used by a 5GMSd Client to establish a DASH session via the M4d interface. In order to establish such a session, the 5GMSd AS shall host an MPD as defined in ISO/IEC 23009-1 [32] or TS 26.247 and the MPD URL is known to the 5GMSd Client typically using M8d.

The Media Player receives an MPD URL from the 5GMSd-Aware Application through M7d by methods defined in clause 13. The Media Player shall send an HTTP GET message to the 5GMSd AS including the URL of the MPD resource. On success, the 5GMSd AS shall respond with a 200 (OK) message that includes the requested MPD resource.

Additional procedures for reactions to different HTTP status codes are provided in clause A.7 of TS 26.247 and ISO/IEC 23009-1 [32] clause A.7.

Additional procedures for handling partial file responses are provided in clause A.9 of TS 26.247.

This information is provided through M7d to the application for selection. In addition, the currently used service description parameters are provided as status information through M7d in order for the Media Session Handler to make use of this information, for example for Dynamic Policy and Network Assistance.

The detailed handling of service description information is documented in clause 13.2 of the present document.

4.6.2 Procedures for Progressive Download Session p. 28

This procedure is used by a 5GMSd client to establish a Progressive Download session via the M4d interface. In order to establish such a session, the 5GMSd AS shall host an 3GP/MP4 file as defined in TS 26.247. The 3GP/MP4 URL is known to the Media Player (in this case a progressive download player), typically by using M8d.

The Media Player receives a URL from the 5GMSd-Aware Application through M7d by methods defined in clause 13. The Media Player shall send an HTTP GET message to the 5GMSd AS including the URL of the 3GP/MP4 resource. On success, the 5GMSd AS shall respond with a 200 (OK) message that includes the requested 3GP/MP4 resource.

Additional procedures for reactions to different HTTP status codes are provided in TS 26.247.

4.7 Procedures of the M5 (Media Session Handling) interface p. 29

4.7.1 Introduction p. 29

The M5 APIs are used by a Media Session Handler within a 5GMS Client to invoke services relating to downlink or uplink media streaming at the 5GMS AF.

4.7.2 Procedures for Service Access Information p. 29

4.7.2.1 General p. 29

Service Access Information is the set of parameters and addresses needed by the 5GMSd Client to activate reception of a downlink media streaming session or by a 5GMSu Client to activate an uplink media streaming session for contribution. The data model of the ServiceAccessInformation resource acquired by the Media Session Handler of the 5GMS Client is shown in clause 11.2.3. Service Access Information additionally includes configuration information to allow the Media Session Handler to invoke procedures for dynamic policy (see clause 4.7.3), consumption reporting (clause 4.7.4), metrics reporting (clause 4.7.5) and network assistance (clause 4.7.6).

For downlink media streaming, the Media Session Handler may obtain Service Access Information from either the 5GMSd-Aware Application (via M6d) or the 5GMSd AF (via M5d). In the former case, the Service Access Information is initially acquired by the 5GMSd-Aware Application from the 5GMSd Application Provider via M8d. In the latter case, the Service Access Information is derived by the 5GMSd AF from the Provisioning Session established via M1d.

Typically, the Service Access Information for downlink media streaming includes a media entry point (e.g. a URL to a DASH MPD or a URL to a progressive download file) that can be consumed by the Media Player and is handed to the Media Player through M7d.

If an Edge Resources Configuration with client-driven management (EM_CLIENT_DRIVEN) is provisioned in the applicable Provisioning Session, the 5GMSd AF shall convey the ClientEdgeResourcesConfiguration to the Media Session Handler (via M5d) as part of the Service Access Information.

For downlink media streaming exclusively via eMBMS and for hybrid 5GMSd/eMBMS services as defined in clauses 5.10.2 and 5.10.5 respectively of TS 26.501, the Service Access Information indicates that the 5GMSd Client acts as an MBMS-Aware Application.

For dynamically provisioned downlink media streaming via eMBMS as defined in clause 5.10.6 of TS 26.501, the 5GMSd AS creates a presentation manifest that is regularly polled by the Media Player for a potential update. When an eMBMS User Service carrying the 5GMSd content is dynamically provisioned or removed by the 5GMSd AF, the 5GMSd AS shall update the presentation manifest with the locations where the updated manifest and the media segments are now available, for example to add or change to the media server in the MBMS Client.

For uplink media streaming, the 5GMSu Client may obtain Service Access Information from either the 5GMSu-Aware Application (via M6u/M7u) or the 5GMSu AF (via M5u). In the former case, the Service Access Information is initially acquired by the 5GMSu-Aware Application from the 5GMSu Application Provider via M8u. In the latter case, the Service Access Information is derived by the 5GMSu AF from the Provisioning Session established via M1u.

This clause specifies the procedures whereby the 5GMS Client fetches Service Access Information from the 5GMS AF.

4.7.2.2 Create Service Access Information p. 30

The Create operation is not allowed on Service Access Information.

4.7.2.3 Read Service Access Information properties p. 30

This procedure shall be used by the Media Session Handler to acquire Service Access Information from the 5GMS AF. The Media Session Handler uses the GET method for this purpose.

The downlink or uplink media streaming session for which the Media Session Handler is requesting data is identified by a unique reference contained in the path of the URL, as specified in clause 11.2.2.

Once it has obtained an initial set of Service Access Information, the Media Session Handler shall periodically check for updated Service Access Information by issuing a conditional HTTP GET request containing either:

an If-None-Match request header with the value of the entity tag (ETag) that was returned with the most recently acquired ServiceAccessInformation resource; or else
an If-Modified-Since request header with the Last-Modified value of that most recently acquired resource.

The periodicity of polling for updated Service Access Information shall be guided by the value of the Expires and/or Cache-control: max-age headers that shall be included along with every response message for this procedure.

4.7.2.4 Update Service Access Information properties p. 30

The Update operation is not allowed on Service Access Information.

4.7.2.5 Destroy Service Access Information properties p. 30

The Destroy operation is not allowed on Service Access Information.

4.7.3 Procedures for dynamic policy invocation p. 30

This procedure is used by a Media Session Handler to manage Dynamic Policy Instance resources via the M5 interface. A dynamic policy invocation consists of a Policy Template Id, flow description(s), a 5GMS Application Service Configuration Id and potentially other parameters, according to clause 5.7 of TS 26.501.

A Policy Template Id identifies the desired Policy Template to be applied to an application flow. A Policy Template includes properties such as specific QoS (e.g. background data) or different charging treatments. The 5GMS AF combines the information from the Policy Template with dynamic information from the Media Session Handler to gather a complete set of parameters to invoke the N33 or N5 API call. The Policy Template may contain for example the AF identifier.

The flow description allows the identification and classification of the media traffic, such as the packet filter sets given in clause 5.7.6 of [2].

In order to instantiate a new dynamic policy, the Media Session Handler shall first create a resource for the Dynamic Policy Instance on the 5GMS AF. When the Media Session Handler needs several dynamic policies, it repeats the step as often as needed.

The Media Session Handler creates a new Dynamic Policy Instance by sending an HTTP POST message to the 5GMS AF. The body of the HTTP POST message shall include a Provisioning Session Id, the Policy Template Id and the Service Data Flow description. The Service Data Flow description identifies the actual application flow(s) to be policed according to the Policy Template. If the operation is successful, the 5GMS AF creates a new resource URL representing the Dynamic Policy Instance. In this case, the 5GMS AF shall respond to the Media Session Handler with a 201 Created HTTP response message, including the URL for the newly created Dynamic Policy Instance resource as the value of the Location header field.

When the Dynamic Policy Instance is successfully instantiated, the 5GMS AF triggers the creation of a corresponding policy in the 5G System. Depending on the selected sdfMethod, the 5GMS AF fills in a flowDescription object and / or provides an application identifier referring to a PFD (Packet Flow Description) object containing the domain name.

The Media Session Handler can destroy a Dynamic Policy Instance resource using the HTTP DELETE method. As a result, the 5GMS AF shall trigger the appropriate actions towards other Network Functions like PCF or NEF to remove the associated PCC rule.

4.7.4 Procedures for consumption reporting p. 31

These procedures are used by the Media Session Handler and the Consumption Reporting functions of the 5GMSd Client to submit a consumption report via the M5d interface if Consumption Reporting is applied for a downlink streaming session.

The Service Access Information indicating whether Consumption Reporting is provisioned for downlink streaming sessions is described in clause 11.2.3. When the ClientConsumptionReportingConfiguration.samplePercentage value is 100, the Media Session Handler shall activate the consumption reporting procedure. If the samplePercentage is less than 100, the Media Session Handler shall generate a random number which is uniformly distributed in the range of 0 to 100, and the Media Session Handler shall activate the consumption report procedure when the generated random number is of a lower value than the samplePercentage value.

If the consumption reporting procedure is activated, the Media Session Handler shall submit a consumption report to the 5GMSd AF when any of the following conditions occur:

Start of consumption of a downlink streaming session;
Stop of consumption of a downlink streaming session;
Upon determining the need to report ongoing 5GMS consumption at periodic intervals determined by the ClientConsumptionReportingConfiguration.reportingInterval property.
Upon determining a location change, if the ClientConsumptionReportingConfiguration.locationReporting property is set to True.
Upon determining an access network change (e.g. unicast to eMBMS, or vice versa), if the ClientConsumptionReportingConfiguration.accessReporting property is set to True.

Whenever a consumption report is sent, the Media Session Handler shall reset its reporting interval timer to the value of the reportingInterval property and it shall begin countdown of the timer again. Whenever the Media Session Handler stops the consumption of a downlink streaming session, it shall disable its reporting interval timer.

In order to submit a consumption report, the Media Session Handler shall send an HTTP POST message to the 5GMSd AF. If several 5GMSd AF addresses are listed in the ClientConsumptionReportingConfiguration.serverAddresses array (see Table 11.2.3.1-1), the Media Session Handler shall choose one and send the message to the selected. The request body shall be a ConsumptionReport structure, as specified in clause 11.3.3.1. The server shall respond with a 200 (OK) message to acknowledge successful processing of the consumption report.

The Consumption Reporting API, defining the data formats and structures and related procedures for consumption reporting, is described in clause 11.3.

A reporting client identifier shall be included in the consumption report. If available to the Media Session Handler, its value should be a GPSI value as defined by TS 23.003. Otherwise, the reporting client identifier should be represented by a stable and globally unique string.

4.7.5 Procedures for metrics reporting p. 32

The M5 procedures for QoE metrics reporting pertain to the combination of the provisioning of metrics collection and reporting in the Media Session Handler using relevant Service Access Information, and the sending of collected metrics by the Media Session Handler to the 5GMS AF in accordance with the configured metrics scheme(s). A metrics scheme may be 3GPP-defined or non-3GPP-defined.

When the metrics collection and reporting feature is activated for a downlink media streaming session, one or more metrics configuration sets, each associated with a metrics scheme, may be provided to the 5GMS Client. A given metrics configuration set contains information such as the 5GMS AF address(es) to which metrics are to be sent by the Media Session Handler, metrics reporting interval, target percentage of media streaming sessions for which reports should be sent, and the set of metrics to be collected and reported. See TS 26.501 for additional details.

For progressive download and DASH streaming services, the listed metrics in a given metrics configuration set are associated with the 3GPP metrics scheme and shall correspond to one or more of the metrics as specified in clauses 10.3 and 10.4, respectively, of TS 26.247. Metrics related to virtual reality media, as specified in clause 9.3 of TS 26.118, may also be listed in the metrics configuration. Metrics related to eMBMS delivery, as specified in clause 9.4.6 of TS 26.346, may also be listed in the metrics configuration.

Details of the metrics reporting API are provided in clause 11.4, and for 3GP-DASH based downlink media streaming services, the 3GPP-defined metrics reporting scheme and metrics report format are defined in clause 11.4.3.

A reporting client identifier may be included in the metrics report. If available to the Media Session Handler, its value should be a GPSI value as defined by TS 23.003. Otherwise, the reporting client identifier should be represented by a stable and globally unique string.

4.7.6 Procedures for network assistance p. 32

This procedure is used by the 5GMS Client to request Network Assistance from the 5GMSd AF.

The 5GMS Client first creates a Network Assistance Session. It provides information that will be used by the Network Assistance function to request QoS from the PCF and to recommend a bit rate to the 5GMS Client.

The 5GMS Client may also request a delivery boost to be provided.

After the Network Assistance Session resource is provisioned, the 5GMS Client uses the Network Assistance Session identifier when requesting a bit rate recommendation.

In order to terminate a Network Assistance Session, the 5GMS Client deletes the Network Assistance session resource.

4.8 Procedures of the M6d (UE Media Session Handling) interface p. 33

4.8.1 General p. 33

This clause contains the procedures for the interaction between the 5GMSd-Aware application or the Media Player and the Media Session Handler through the M6d API. Details are provided in clause 12.

4.8.2 Consumption reporting procedures p. 33

Before a streaming session is started, the Media Session Handler shall check if the Service Access Information contains any Consumption reporting configuration, as specified in clause 4.7.3. If such a configuration is present, the Media Session Handler shall initiate consumption reporting based on this configuration for the current streaming session.

The Media Session Handler shall first determine whether consumption reporting is active for the session. The determination shall be based on the samplePercentage attribute specified in the consumption reporting configuration. When the samplePercentage is not present or its value is 100, consumption reporting is active for the session. If the samplePercentage is less than 100, the Media Session Handler generates a random number which is uniformly distributed in the range 0 to100; consumption reporting is active for the session when the generated random number is of a lower value than the samplePercentage value.

If consumption reporting for this session is active, the Media Session Handler shall regularly determine the consumption reporting parameters defined in clause 11.3.2.4 from the Media Player through the M7d interface and shall report these values according to the reportingInterval specified in the Client Consumption Reporting Configuration.

4.9 Procedures of the M7d (UE Media Player) interface p. 33

4.9.1 General p. 33

This clause contains the procedures for the interaction between the 5GMSd-Aware Application or the Media Session Handler and the Media Player through the M7d API. Details are provided in clause 13.

4.9.2 Metrics reporting procedures p. 33

These procedures shall be used by the Media Session Handler function to control metrics reporting when such reporting is configured via metadata sent in-band via the media manifest.

When a streaming session is started, the Media Session Handler shall check if the manifest contains any metrics configuration, as specified in clauses 10.4 and 10.5 of TS 26.247, or clause 9.3 of TS 26.118. If such a configuration is found, the Media Session Handler shall use it for the current streaming session.

The Media Session Handler shall first determine whether metrics from this session shall be reported. The determination shall be based on the samplePercentage attribute specified in the metrics configuration, according to clause 10.5 of TS 26.247.

If metrics are reported for the session, the Media Session Handler shall request the Media Player to create a metrics collection job. The Media Player shall return a reference to the created job, which the Media Session Handler shall use in all subsequent actions related to this job.

The Media Session Handler shall configure the metrics collector job with the set of metrics which shall be collected during the session. The format of the configuration shall be according to TS 26.247 Annex L.2, but note that only the metrics attribute in the configuration shall be used for this purpose.

The Media Session Handler shall regularly request the collected metrics from the Media Player according to the reportingInterval specified in the metrics configuration. The metrics returned by the Media Player shall use the format as described in clause 10.6 of TS 26.247 and (for virtual reality media) in clause 9.4 of TS 26.118 and the Media Session Handler shall forward these to the server address(es) specified in the metrics configuration using the specified DNN according to the procedures described in clause 10.6 of TS 26.247.

When the session is finished the Media Session Handler shall delete the metrics collection job.

4.10 Procedures of the M8d interface p. 34

This clause defines basic procedures for M8d.

No specific procedures are defined but it is expected that the 5GMSd Application Provider can provide media session entry points to a 5GMSd-Aware Application through M8d. The 5GMSd-Aware Application would then initiate the media session by providing such an entry point to the 5GMSd Client through M7d.

4.11 Data collection and reporting procedures at reference point R4 |R17| p. 34

4.11.1 General p. 34

These procedures are used by the 5GMS AS, as a type of data collection client, to acquire its data collection and reporting client configuration from, and subsequently report media streaming access activity to, the Data Collection AF instantiated in the 5GMS AF. It does so by invoking the Ndcaf_DataReporting service offered by the Data Collection AF at reference point R4, as specified in clause 7 of TS 26.532.

4.11.2 5GMS AS data collection and reporting client configuration p. 34

The 5GMS AS shall use the service operations and procedures specified in TS 26.532 to obtain its data collection and reporting client configuration from the Data Collection AF instantiated in the 5GMS AF at reference point R4:

In the case where both the 5GMS AS and the 5GMS AF reside in the trusted domain, the 5GMS AS shall obtain its data collection client configuration directly from the Data Collection AF by invoking appropriate Ndcaf_DataReporting service operations as specified in clause 7.2 of [49] according to the procedures specified in clauses 4.2.5 of TS 26.532.
Should the 5GMS AS and the 5GMS AF reside in different trust domains, the 5GMS AS shall instead obtain its configuration from the Data Collection AF indirectly via the NEF by invoking the equivalent operations on the Nnef_DataReporting service as defined in TS 26.531.

In both cases, the 5GMS AS shall declare that it supports the MS_ACCESS_ACTIVITY data reporting domain in DataReportingSession.supportedDomains (see clauses 7.2.3.2.1 and 7.2.3.3.1 of TS 26.532) and the Data Collection AF instantiated in the 5GMS AF shall request reporting for this domain by including the same value as a key to the DataReportingSession.reportingConditions dictionary. The value of the ReportingCondition.type property at this key shall be INTERVAL, THRESHOLD or OFF.

The 5GMS AS shall refresh its data collection and reporting client configuration according to the procedures specified in clause 4.2.5.3 of TS 26.532.

4.11.3 5GMS AS data reporting p. 35

The 5GMS AS shall use the service operations and procedures specified in TS 26.532 to report media streaming access activity to the Data Collection AF instantiated in the 5GMS AF at reference point R4:

In the case where both the 5GMS AS and the 5GMS AF reside in the trusted domain, the 5GMS AS shall submit media streaming access activity reports directly to the Data Collection AF by invoking appropriate Ndcaf_DataReporting service operations as specified in clause 7.3 of TS 26.532 according to the procedures specified in clauses 4.2.7 of TS 26.532.
Should the 5GMS AS and the 5GMS AF reside in different trust domains, the 5GMS AS shall instead submit media streaming access activity reports indirectly to the 5GMS AF via the NEF by invoking the equivalent operations on the Nnef_DataReporting service as defined in TS 26.531.

In both cases, the conditions for sending a downlink media streaming access activity report by the 5GMSd AS and the parameters of such report are signalled in the data collection and reporting client configuration obtained using the procedure specified in clause 4.11.2.

In order to submit a media streaming access activity report, the 5GMS AS shall send an HTTP POST message to the Data Collection AF instantiated in the 5GMS AF. The request body shall be a JSON document of type DataReport (as defined in clause 7.3.3.2.1 of TS 26.532) containing one or more MediaStreamingAccessRecord structures, as specified in clauses 17.2 and C.5.1 of the present document.

The Data Collection AF shall respond with a 200 (OK) message to acknowledge successful processing of the media streaming access activity report.

4.12 Event Exposure procedures at reference points R5 and R6 |R17| p. 35

4.12.1 General p. 35

As specified in clauses 4.7.1 and 4.7.4 of TS 26.501, Events relating to 5G Media Streaming are exposed to Event consumers at reference points R5 and R6 by the Data Collection AF instantiated in the 5GMS AF (playing the role of Event service provider). Procedures for event exposure are specified in clauses 5.11.3 (for downlink media streaming) and 6.8.3 (for uplink media streaming) respectively of [2].

The following Naf_EventExposure service operations as defined in TS 23.502 apply for such interactions between the Data Collection AF and consumer entities:

Naf_EventExposure_Subscribe,
Naf_EventExposure_Unsubscribe, and
Naf_EventExposure Notify.

In this release, eligible Event service consumers of 5GMS Event services are the NWDAF and NEF as NFs, and the Event Consumer AF of the 5GMS Application Provider.

4.12.2 Event Exposure subscription procedure p. 35

The definition of input and output parameters of the Naf_EventExposure_Subscribe service operation is identical to that specified in clause 5.2.19.2.2 of TS 23.502, except that "AF" is replaced by "Data Collection AF" and "consumer NF" (or "NF consumer") is replaced by "Event service consumer".

4.12.3 Event Exposure unsubscription procedure p. 35

The definition of input and output parameters of the Naf_EventExposure_Unsubscribe service operation is identical to that specified in clause 5.2.19.2.3 of TS 23.502, except that "AF" is replaced by "Data Collection AF" and "consumer NF" (or "NF consumer") is replaced by "Event service consumer".

4.12.4 Event Exposure notification procedure p. 36

The definition of input and output parameters of the Naf_EventExposure_Notify service operation is identical to that specified in clause 5.2.19.2.4 of TS 23.502, except that "AF" is replaced by "Data Collection AF" and "consumer NF" (or "NF consumer") is replaced by "Event service consumer".

4.13 Procedures for downlink media streaming via eMBMS |R17| p. 36

This procedure is used by a 5GMSd Client to establish a 5GMSd session either completely, or at least partially, through eMBMS.

For downlink media streaming exclusively via eMBMS and for hybrid 5GMSd/eMBMS services, as defined in clauses 5.10.2 and 5.10.5 respectively of TS 26.501:
- The 5GMSd Application Provider shall provision a supplementary distribution network of type DISTRIBUTION_NETWORK_EMBMS in the Content Hosting configuration at reference point M1d, as specified in clause 7.6.3.1, with either MODE_EXCLUSIVE or MODE_HYBRID (as appropriate).
- The 5GMSd Application Provider may additionally provision access reporting in the Consumption Reporting Configuration at M1d, as specified in clause 7.7.3.1.
- The MBMS Client shall host an MPD as defined in ISO/IEC 23009-1 [32] or in TS 26.247, or any other presentation manifest as the 5GMSd Media Entry Point such as an HLS Master Playlist.
- The URL of this presentation manifest shall be signalled to the 5GMSd Client through the 5GMSd session establishment procedure.
- The MBMS Client shall be invoked by the Media Session Handler via reference point MBMS-API-C using the procedures defined in TS 26.347.
For dynamically provisioned downlink media streaming via eMBMS as defined in clause 5.10.6 of TS 26.501:
- The 5GMSd Application Provider shall provision a supplementary distribution network of type DISTRIBUTION_NETWORK_EMBMS in the Content Hosting configuration at reference point M1d, as specified in clause 7.6.3.1, with MODE_DYNAMIC.
- The 5GMSd Application Provider shall additionally provision access reporting in the Consumption Reporting Configuration at M1d, as specified in clause 7.7.3.1.
- The 5GMSd AS shall host an MPD as defined in ISO/IEC 23009-1 [32] or in TS 26.247, or any other presentation manifest as the 5GMSd Media Entry Point.
- The URL of this presentation manifest shall be signalled to the 5GMSd Client through the 5GMSd session establishment procedure. If the 5GMSd service is currently available as an MBMS User Service, the 5GMSd Client forwards the manifest request to the MBMS Client; otherwise, it forwards the request to the 5GMSd AS via reference point M4d.
  
  NOTE:
  The detailed execution of dynamically handling this decision is left to implementation.
- The MBMS Client shall be invoked dynamically, paused or destroyed by the Media Session Handler via reference point MBMS-API-C using the procedures defined in TS 26.347.

Additional procedures for reactions to different HTTP status codes are provided in clause A.7 of TS 26.247 and clause A.7 of ISO/IEC 23009-1 [32].

Additional procedures for handling partial file responses are provided in clause A.9 of TS 26.247.