Question: What triggers the measurement of 'Attempted PS SMS mobile originating' in a UMTS/GSM network, according to the SGSN's function in packet switching?
Option 1: Transmission by the SGSN of 'RP-ACK' Message to the MS.
Option 2: Receipt by the SGSN of 'RP-DATA' Message from the MS.
Option 3: Successful delivery of SMS to the destination User Equipment (UE).
Option 4: Initiation of a PS SMS mobile originating request by the network.
Explanation: The correct answer is Option 2 because the trigger point for 'Attempted PS SMS mobile originating' measurements is the receipt by the SGSN of an 'RP-DATA' Message from the MS, indicating an attempt to originate a PS SMS from the mobile station. This aligns with measuring attempts rather than successes.