Question: What triggers the VAL (Vertical Application Layer) server to update existing MBS (Multicast/Broadcast Service) sessions via the NRM (Network Resource Management) server?
Option 1: Periodic network maintenance schedules
Option 2: Changes in User Equipment (UE) mobility patterns within a cell
Option 3: Emerging service requirements or changes in service area parameters during the MBS session lifecycle
Option 4: Automatic response to detected network congestion
Explanation: The correct answer, Option 3, reflects the scenario where the VAL server updates MBS sessions in response to new or altered service needs or modifications in the defined service area. This is a direct application of telecom concepts related to session management and resource allocation, highlighting the dynamic nature of service provisioning in vertical applications. Options 1, 2, and 4, while plausible in other network management contexts, do not directly align with the specified triggers for updating MBS sessions as per the given context.