Question: Under what condition must the network re-run the RRC UE Capability Transfer Procedure after initially acquiring UE capabilities via this procedure?
Option 1: When the UE switches from LTE to NR (5G) network
Option 2: After a successful AS SMC procedure, if UE capabilities were acquired before AS security activation (excluding unauthenticated emergency calls and Control plane CIoT optimization UEs)
Option 3: Upon receipt of a new UE radio capability ID from the User Equipment
Option 4: When the network's security protocol is updated to a newer version
Explanation: This is because, as per the specified security architecture, activating AS (Access Stratum) security via a successful AS SMC (Security Mode Command) procedure is mandatory before relying on the UE capabilities transferred through RRC (Radio Resource Control) messages. If these capabilities were obtained prior to securing the connection, they are considered untrusted and must be re-acquired post-security activation to ensure the integrity of the network and its communications. This rule specifically excludes scenarios like unauthenticated emergency calls and UEs utilizing Control Plane CIoT (Cellular Internet of Things) optimization, where different security protocols may apply.