Question: In the context of Lawful Interception (LI) as per 3GPP standards, what is the treatment of the first call that encounters a busy subscriber in relation to Completion of Call to Busy Subscriber (CCBS) and its associated IRI for LI purposes?
Option 1: The first call's IRI information is always sent to the Law Enforcement Agency (LEA) for potential future CCBS attempts.
Option 2: The call is not subject to LI, but CCBS recall procedures are intercepted.
Option 3: The first call's encounter with a busy subscriber triggers immediate CCBS-related LI procedures.
Option 4: The first call is treated as a standard busy call, with no CCBS-related IRI information sent for LI purposes until a new call attempt is made.
Explanation: According to the principles of Lawful Interception in the context of 3GPP standards, regarding Completion of Call to Busy Subscriber (CCBS), when the first call meets a busy subscriber and is released, it doesn't generate CCBS-related IRI for LI purposes. It's handled as any standard call that encounters a busy destination, without triggering specific CCBS procedures until a new attempt to reach the terminating user is initiated. Thus, no special IRI for CCBS is generated or sent for this initial encounter.