Diameter Usage Start Time

To determine which offers and balances are valid at the time of rating and to perform time normalizations, the MATRIXX Charging Application uses its own internal view of time, which is derived from the MtxDiamRoMsg MDC EventTime field. For rating based on data volume (rather than duration), this time is always the EventTime. For rating based on duration, the MATRIXX Charging Application can segment the event based on time.

The EventTime value is used to set the usage start time of the session portion being rated. For sessions that include multiple service contexts, a usage start time is defined for each service context.

The usage start time is set according to the current operation by the Diameter Credit-Control application, as follows:
  • For a Start message, it is the EventTime of the current message.
  • For an Interim message, while rating the used quantity, it is the EventTime of the previous message in the session (CC Start or CC Interim message). While rating the requested quantity, it is the EventTime of the current message.
  • For a Stop message, it is the EventTime of a previous message in the session (CC Start or CC Interim message).
  • For a CC Event, it is the EventTime of the current message.

In general, the authorization of the quota, and the subsequent usage of that quota are rated starting from the EventTime of the authorization. For unauthorized usage, rating starts from the EventTime of the usage.