Question: What is the primary purpose of Serving PLMN Rate Control in an Evolved Packet System (EPS) network?
Option 1: To manage the quality of service for NAS Data PDUs.
Option 2: To protect the serving network from excessive load generated by NAS Data PDUs.
Option 3: To prioritize signaling radio bearers in the E-UTRAN.
Option 4: To limit the number of PDN connections per user.
Explanation: Serving PLMN Rate Control is configured to protect the serving network, including the MME and Signalling Radio Bearers in the E-UTRAN, from excessive load generated by NAS Data PDUs. This is achieved by defining a maximum number of NAS Data PDUs that can be transferred per 6-minute interval.