Question: What is the primary purpose of the eNB CP Relocation Indication procedure for NB-IoT UEs using Control Plane CIoT EPS optimizations?
Option 1: To initiate a handover procedure from one eNB to another without UE involvement.
Option 2: To request the MME to authenticate the UE's re-establishment request and establish a new S1-connection after RRC Re-establishment.
Option 3: To release existing S1 resources due to authentication failure during initial attach.
Option 4: To notify the UE about changes in eNB configuration without impacting ongoing sessions.
Explanation: The correct answer, Option 2, accurately reflects the purpose of the eNB CP Relocation Indication procedure as described. This procedure is specifically designed to handle the authentication of a UE's re-establishment request by the MME and subsequently initiate the setup of a new logical S1-connection after the UE has triggered an RRC Re-establishment procedure in an eNB, particularly for NB-IoT UEs leveraging Control Plane CIoT EPS optimizations. This ensures secure and efficient re-establishment of connectivity. The other options either misrepresent the procedure's application (Option 1), its outcome (Option 3), or its scope (Option 4).