Question: In a Telecommunication Charging Data Record (CDR), what does the 'Session ID' field primarily contain for a SIP-initiated session?
Option 1: The Session ID contains the SIP CALL ID of the SIP session, as defined in RFC 3261.
Option 2: A unique identifier generated by the charging gateway for billing purposes.
Option 3: The data coding scheme used within Short Messages (SM) corresponding to TP-DCS headers.
Option 4: An indication of whether a delivery report is requested for the session.
Explanation: In telecom management and Charging Data Records, the Session ID field identifies specific sessions. For SIP-initiated sessions, it contains the SIP CALL ID (defined in RFC 3261), ensuring traceability and accurate billing for SIP-based services.