Question: Under what circumstances can the SGSN initiate a modification of an existing BSS packet flow context, and what procedure is utilized for this purpose?
Option 1: During an ongoing PS Handover procedure, using the dedicated BSS Packet Flow Context Modification Procedure.
Option 2: At any time due to changes like PDP context activation/modification/deactivation or UE-AMBR value modification, utilizing the BSS Packet Flow Context Creation procedure.
Option 3: Only when a new MS attaches to the network, using a unique Network Attachment Procedure.
Option 4: Exclusively for QoS adjustments, employing a separate QoS Adjustment Procedure.
Explanation: The SGSN can initiate modifications to existing BSS packet flow contexts due to updates like PDP context changes or UE-AMBR value modifications. Utilizing the BSS Packet Flow Context Creation procedure for overwriting existing parameters with modified ones is a practical approach, ensuring seamless service delivery without unnecessary overhead.