Question: What triggers an eNodeB (eNB) or gNodeB (gNB) to send a Criticality Diagnostics Information Element (IE) over the X2 interface in an E-UTRAN?
Option 1: Successful handover of a User Equipment (UE) from one cell to another.
Option 2: Receipt of a message with unrecognized or missing Information Elements (IEs) or logical errors.
Option 3: Periodic reporting of cell load information to neighboring eNBs/gNBs for resource optimization.
Option 4: Initialization of the X2 interface between two eNBs/gNBs during network setup.
Explanation: The Criticality Diagnostics IE is specifically sent in response to issues with message comprehension, such as unrecognized or missing IEs, or the presence of logical errors within a received message. This mechanism helps in identifying and potentially resolving communication problems between eNBs/gNBs over the X2 interface, ensuring the integrity and effectiveness of the E-UTRAN.