Discussion: TS26.512 - How is consumption reporting triggered?

[shilinding]

Problem description

The conditions for submitting a consumption report to the 5GMSd AF defined in TS26.512-h40 clause 4.7.4 are:

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:

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

Questions:

• About 1 and 2, in Exoplayer, when PlaybackState changed to Player.STATE_BUFFERING (or it should be Player.STATE_READY?) it indicates the starting of the session, and PlaybackState Changed to Player.STATE_ENDED indicates the stopping of the session. Correct?
• About 4 and 5, how can we know the changing of the configuration, do we request ServiceAccessInformation from AF and get configuration from it and check if the two configuration setting to true all the time? I don't think so.

[rjb1000]

About 4 and 5, how can we know the changing of the configuration, do we request ServiceAccessInformation from AF and get configuration from it and check if the two configuration setting to true all the time? I don't think so.

The Service Access Information retrieved from the 5GMS AF at reference point M5 will be accompanied by a time-to-live value in the Cache-Control: max-age HTTP response header. For a long-lived media streaming session (i.e., one that goes on longer than the Service Access Information's time-to-live period), a sensible implementation of the Media Session Handler would re-request the Service Access Information from the 5GMS AF and start or stop consumption reporting according to the up-to-date configuration.

A high quality implementation of the Media Session Handler would re-request the Service Access Information using a conditional HTTP GET request, i.e. one that uses the If-Modified request header with an ETag value previously returned by the 5GMS AF or an If-Modified-Since request header with the Last-Modified value of the previous response. This then allows the Media Session Handler to receive a 304 Not Modified response if there is no change to the Service Access Information, and just reset the time-to-live value per the new Cache-Control: max-age HTTP response header.

The reference implementation of the 5GMS AF should provide both ETag and Last-Modified response headers at reference point M5. Please raise a bug issue against the AF if you find different.

[rjb1000]

Is this issue resolved to your satisfaction, @shilinding?