Question: In a PCC architecture, after linking a new Gateway Control session with an active Gx session, what determines whether the PCRF applies specific procedures?
Option 1: Receipt of a new Quality of Service (QoS) request from the Policy Enforcement Point (PEP)
Option 2: Expiration of a predefined timer set during session establishment
Option 3: Indication of IP flow mobility, such as a ROUTING_RULE_CHANGE event trigger, received from the active Gx session
Option 4: Change in the User Equipment's (UE) location, triggering a new Tracking Area Update
Explanation: The PCRF's decision depends on receiving an indication of IP flow mobility (e.g., a ROUTING_RULE_CHANGE event trigger) from the active Gx session after linking sessions. This signifies changes in routing rules, crucial for managing IP flow mobility, influencing the PCRF's subsequent actions.