Question: What triggers the counting of a successful messaging session establishment in Session-Mode, as per the Performance Management measurement MSG.SuccSessionSM?
Option 1: Receipt of an ACK message from both participants after session initiation.
Option 2: Transmission by the Application Server (AS) of a SIP 200 OK message indicating successful session setup.
Option 3: Completion of the first message exchange between the two participants.
Option 4: Establishment of a dedicated bearer for the messaging service.
Explanation: The correct answer is Option 2 because, according to the provided context, the measurement of successful messaging session establishments in Session-Mode is triggered by the transmission of a SIP 200 OK message by the Application Server (AS), signaling that the messaging session has been successfully established for both participants. This specific event (SIP 200 OK message) is the defined point at which the success of the session establishment is confirmed and counted.