Question: In a subsequent GSM to UMTS handover requiring a circuit connection, what happens to the circuit between 3G_MSC-A and MSC-B after a successful handover when the UE/MS moves into the area of a third 3G_MSC (3G_MSC-B')?
Option 1: The circuit between 3G_MSC-A and MSC-B is released.
Option 2: A new circuit is established between 3G_MSC-A, MSC-B, and 3G_MSC-B'.
Option 3: The existing circuit between 3G_MSC-A and MSC-B is modified to include 3G_MSC-B'.
Option 4: The decision to release or modify the circuit is left to the network operator's policy.
Explanation: After a successful subsequent handover, especially in scenarios involving movement into a new area, releasing unnecessary resources is crucial for network efficiency. Thus, after the UE/MS successfully hands over to a new area (under 3G_MSC-B'), the circuit between 3G_MSC-A and MSC-B would no longer be needed, as the call's connection point has changed. Releasing this circuit ensures resource optimization and reduces unnecessary network load.