How Metering Works
Metering requires coordination between the content provider service (the content owner and license issuer), a metering aggregation service (a service that collects and processes metering data), and participating device manufacturers.
The basic process of metering is as follows. The numbered steps correspond to numbers in the diagram that follows this list:
- The metering aggregation service gives the license issuer a metering certificate, which contains a metering ID and a URL indicating where metering data will be reported. Then, the license issuer includes the metering certificate in the licenses for content that requires metering.
- End users acquire this content and receive a license for it through the standard license acquisition process.
- A media player on a computer or device opens this content license. The DRM component of the media player records metering data, which includes a tally of the number of times the content is used, the type of action performed, and the metering ID.
Note When recording metering data, the media player uses the license key ID to tally the counted actions. So, to track metering information for individual content items, you must protect each content item using a unique key ID.
- A metering plug-in or application on the computer periodically requests metering data for a specific metering ID and then sends the data to the corresponding metering aggregation service. If a Web-enabled device is used, the device can send metering data directly to the metering aggregation service.
This metering data can be decrypted only by the metering aggregation service that owns the metering certificate containing this ID.
For example, suppose a user subscribes to two music services and downloads metered content from each. The metering plug-in for one of the services requests metering data for its metering ID. Only metering data for that ID is gathered, and then it is sent to the corresponding metering aggregation service.
A transaction ID is created at this time for the items that are reported.
- After the metering aggregation service receives and processes the metering data, the service returns a response to the media player, prompting the player to clear the metering data that was reported. The transaction ID is saved until a reporting transaction has been completed. If the process of reporting metering data is interrupted, the transaction ID identifies which data to resend, thereby ensuring that a transaction is complete before clearing the data store.
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