Question: What is the primary purpose of Serving PLMN rate control in EPS?
Option 1: To protect the MME and signalling radio bearers from load generated by NAS messages with user data over control plane.
Option 2: To limit the rate at which the UE generates downlink NAS messages with user data over control plane.
Option 3: To discard or delay NAS messages including user data over control plane that exceed a certain size.
Option 4: To inform the UE of any local serving PLMN rate control during the default EPS bearer context activation procedure.
Explanation: Serving PLMN rate control is primarily used to protect the MME and signalling radio bearers in the E-UTRAN from load generated by NAS messages with user data over control plane, ensuring that the network can handle the traffic without being overwhelmed.