Question: What are the two ways to control the rate of user data sent to and from a UE using CIoT EPS Optimisations?
Option 1: Serving PLMN Rate Control only
Option 2: APN Rate Control only
Option 3: AMBR mechanisms
Option 4: Both Serving PLMN Rate Control and APN Rate Control
Explanation: The rate of user data sent to and from a UE using CIoT EPS Optimisations can be controlled in two different ways, namely Serving PLMN Rate Control and APN Rate Control. Serving PLMN Rate Control is used to protect the MME and Signalling Radio Bearers in the E-UTRAN from load generated by NAS Data PDUs, while APN Rate Control allows HPLMN operators to offer customer services such as "maximum of Y messages per day".