Question: When a Traffic Detection Function (TDF) detects that a usage threshold for a monitoring key is reached, what action does it take regarding notification and reporting to the Policy and Charging Rules Function (PCRF)?
Option 1: Sends a CCR command with CC-Request Type AVP set to "INITIAL_REQUEST" without accumulated usage.
Option 2: Notifies the PCRF by including the "USAGE_REPORT" Event-Trigger in a CCR command with CC-Request Type AVP set to "UPDATE_REQUEST" and reports the accumulated usage.
Option 3: Only updates its internal counters without notifying the PCRF until session termination.
Option 4: Triggers a new TDF session for continued monitoring without reporting the threshold breach.
Explanation: This is correct because, when a usage threshold is reached, the TDF must notify the PCRF and report the accumulated usage. This is done by including the "USAGE_REPORT" Event-Trigger in a CCR command with the CC-Request Type AVP set to "UPDATE_REQUEST", ensuring the PCRF is updated on the usage status for policy and charging control decisions.