Question: In a Vertical Application Layer (VAL) service communication, what can be modified by the NRM server when managing unicast resources?
Option 1: Only activation and deactivation of the bearer
Option 2: Modification of QoS characteristics (e.g., bearer priority adjustment), GBR due to application requirements, and activation/deactivation of the bearer
Option 3: Just modification of GBR due to application requirement
Option 4: None of the above; NRM server cannot modify existing bearers
Explanation: In managing unicast resources for a Vertical Application Layer (VAL) service, the Network Resource Management (NRM) server can adjust various aspects of the bearer. This includes basic control (activation/deactivation), fine-tuning QoS characteristics (e.g., bearer priority), and modifying Guaranteed Bit Rate (GBR) based on evolving application requirements, making Option 2 the most comprehensive and correct answer.