Question: In the context of Performance Management (PM) for a Home enhanced Node B (HeNB) Subsystem (HeNS), what triggers the increment of the 'Number of initial E-RABs successfully established' measurement per QCI?
Option 1: Receipt of an INITIAL CONTEXT SETUP REQUEST message by the HeNB
Option 2: Transmission by the HeNB of an INITIAL CONTEXT SETUP RESPONSE message
Option 3: Successful completion of the E-RAB setup handshake between the UE and the HeNB
Option 4: Periodic reporting of performance metrics from the HeNB to the Operations and Maintenance (O&M) system
Explanation: The correct answer is Option 2 because it is specifically upon the transmission by the HeNB of an INITIAL CONTEXT SETUP RESPONSE message that each E-RAB successfully established is added to the relevant measurement per QCI, confirming and logging the successful establishment of initial E-RABs.