5GMS: Media streaming session identifier

[rjb1000]

Context

The UE data collection, reporting and event exposure architecture is instantiated in the 5G Media Streaming architecture from Release 17 onwards.

Problem description

According to the current version of TS 26.512 (V17.5.0):

• With the exception of media streaming access activity, a recipient of exposed events is unable to correlate events of a certain type (e.g. QoE metrics) that are part of the same media streaming session.
• A recipient of exposed events is unable to correlate events of one type (e.g. QoE metrics) with those of another type (e.g. consumption reporting).

Suggested solution

A new media streaming session identifier is created by the Media Session Handler each time a new streaming session is initiated.

The media streaming session identifier must not contain any user-identifying data, such as IP addresses or content identifiers. A UUID would be suitable for this purpose, for example.

• The media streaming session identifier is passed as a context parameter when invoking client APIs at reference points M6 and M7.
• The media streaming session identifier is passed when the Media Session Handler invokes services at reference point M5.
• The media streaming session identifier is passed when the Media Player consumes media at reference point M4d.
• The media streaming session identifier is passed when the Media Streamer contributes media at reference point M4u.
• The media streaming session identifier is passed when the Data Collection Client instantiated in the Media Session Handler submits a data report to a Data Collection AF instantiated in the 5GMS AF at reference point R2.
• The media streaming session identifier is passed when the 5GMS AS submits a data report to a Data Collection AF instantiated in the 5GMS AF at reference point R4.

Changes proposed at reference point M5

To address the problems identified above, a media streaming session identifier property is added to the following data types at reference point M5:

1. ConsumptionReport (clause 11.3.3.1).
2. MetricsReport (clause 11.4.3).
   • All metrics reporting schemes to be used in connection with 5G Media Streaming need to convey the media streaming session identifier somehow.
   • In the case of the PSS metrics reporting scheme for DASH, the QoEReport@recordingSessionId attribute is designed to play this role.
     • (The length of this attribute is limited by TS 26.247 clause 10.6.2 to two octets only; this restriction could be relaxed there, or else overridden by TS 26.512.)
3. DynamicPolicy resource (clause 11.5.3.1).
   • Additional property supplied by the Media Session Handler when instantiating a Policy Template.
4. NetworkAssistanceSession resource (clause 11.6.3.1).
   • Additional property supplied by the Media Session Handler when creating a new Network Assistance session.
   • Media streaming session identifier associated with individual Network Assistance invocations within the scope of this Network Assistance session.

Changes proposed at reference point M4

For HTTP-based media consumption at reference point M4d and HTTP-based media contribution at reference point M4u, a custom HTTP header field is defined by TS 26.512 to convey the media streaming session identifier in HTTP requests from the 5GMS Client to the 5GMS AS. This enables the 5GMS AS to populate the corresponding field in the media streaming access record delivered to the Data Collection AF at reference point R4.

For example, 3gpp-Media-Session-Id, with the value following the format of those specified in TS 29.500 clause 5.2.3 and RFC 9110 section 5.6.

Specifically:

1. Either:
   1. Add an item to the list of M4d requirements in TS 26.512 clause 10.2 specifying the HTTP request header or
   2. Specify the HTTP request header as part of the 5G Media Streaming DASH Interoperability Point in TS 26.247 clause 7.3.11.
      • (TS 26.247 clause 7.3.11 mainly deals in requirements on the MPD rather than the application protocol layer, so may not be appropriate.)

Changes proposed at reference point M6 (Media Session Handling APIs)

The media streaming session identifier needs to be present in all notifications produced by the Media Session Handler at reference point M6.

Specifically:

1. Add Media streaming session identifier to the set of internal properties defined in TS 26.512 clause 12.2.2.2 and clarify that a separate set of properties exists for each media streaming session currently managed by the Media Session Handler.
2. Add Media streaming session identifier to the payload all notification events defined in TS 26.512 clause 12.2.3.

Changes proposed at reference point M7 (Media Stream Handling APIs)

The media streaming session identifier needs to be passed as a parameter to all API methods invoked on the Media Stream Handler at reference point M7 and present in all notifications produced by the Media Stream Handler at this reference point.

Specifically:

1. Add a sentence to the end of TS 26.512 clause 13.2.3.1 indicating that all methods take a media streaming session identifier as a mandatory parameter.
2. Add a media streaming session identifier as a status parameter in table 13.2.4-1.
3. Add Media streaming session identifier to the payload all notification events defined in TS 26.512 table 13.2.5-1.
4. Add Media streaming session identifier as an additional dynamic status parameter in TS 26.512 table 13.2.6-1.

[rjb1000]

No time to progress this in the current meeting cycle, so kicking the can down the road for now...

[rjb1000]

(Unlikely that this will be fixed in Rel-17 now. Let's focus on Rel-18.)

[rjb1000]

The following contributions were made to SA4#107 (Sophia Antipolis):

• TS 26.247
  • Rel-18: CR0184 "[5GMS_Pro_Ph2] Carriage of media delivery session ID in QoE report" in S4-240095
• TS 26.510
  • Rel-18: pCR "[5GMS_Pro_Ph2] Media delivery session identification and life-cycle" in S4-240100

Both contributions were agreed.

• The TS 26.247 CR goes forward to SA#103 (Maastrict) for approval.
• The TS 26.510 pCR has already been implemented in the Editor's draft.