Question: In a 3GPP Access (PMIP-based) network, what triggers the Bearer Binding and Event Reporting Function (BBERF) to re-evaluate the bearer binding, in addition to a default bearer QoS change?
Option 1: Receipt of new UE location update over S1 interface
Option 2: QoS Rule operation requested by the Policy and Charging Rules Function (PCRF)
Option 3: Handover request from a non-3GPP access network
Option 4: Expiration of a predefined QoS enforcement timer
Explanation: In the context of 3GPP Access with PMIP, the BBERF's re-evaluation of bearer binding is triggered not just by changes in the default bearer QoS but also by specific requests from the PCRF, namely QoS Rule operations. This ensures dynamic adjustment of resources based on policy decisions, highlighting the interplay between QoS management and policy control in telecom networks.