Question: When a UE requests to retrieve a held call, how does the MSC Server instruct the Media Gateway (MGW) to re-establish communication with the held party?
Option 1: By releasing the existing bearer termination and establishing a new one.
Option 2: By keeping the through-connection of the bearer termination one-way until the call is answered.
Option 3: By using only the Split Bearer Termination Procedure for all retrieval requests.
Option 4: By changing the through-connection of the bearer termination to be both-way through-connected or by using the Join Bearer Termination Procedure.
Explanation: This is correct because, according to telecom protocols for handling held calls, when a UE requests to retrieve a held call, the MSC Server re-establishes two-way communication. This is achieved by either modifying the existing bearer's connection setup for both-way communication or using the Join Bearer Termination Procedure, reconnecting call paths for seamless retrieval. This ensures voice/data transmission in both directions once the held call is retrieved, facilitating normal call interaction.