Question: What triggers the counting of a successful outgoing handover to GERAN per cause in HeNS Performance Management?
Option 1: Receipt of a UE CONTEXT MODIFY REQUEST message from the MME to the HeNB.
Option 2: Receipt of a S1AP message UE CONTEXT RELEASE COMMAND sent from the MME to the HeNB, indicating a successful handover initiated due to a specific cause.
Option 3: Successful establishment of a new S1-U bearer for the handed-over UE at the target GERAN cell.
Option 4: Expiration of a timer set during the handover initiation process, confirming handover success.
Explanation: The correct answer is based on the specific trigger mentioned in the context of HeNS Performance Management for counting successful outgoing handovers to GERAN. This requires understanding how handover success is confirmed and measured in telecom networks, particularly in the context of HeNB subsystems interacting with other network elements like the MME. The S1AP UE CONTEXT RELEASE COMMAND message serves as this trigger, indicating a successful handover due to a specific cause, which is crucial for performance measurement and management.