Question: What action should a UE take if AS security is not started and radio link failure occurs before successful delivery of ULInformationTransfer messages has been confirmed by lower layers?
Option 1: The UE shall ignore the failure and continue with normal operations.
Option 2: The UE shall re-establish PDCP for all SRBs.
Option 3: The UE shall inform upper layers about the possible failure to deliver the information contained in the concerned ULInformationTransfer messages, unless the messages only include dedicatedInfoF1c.
Option 4: The UE shall release all ongoing procedures and initiate a new RRC connection.
Explanation: According to the specifications, if AS security is not started and radio link failure occurs before successful delivery of ULInformationTransfer messages has been confirmed by lower layers, the UE should inform upper layers about the possible failure to deliver the information contained in the concerned ULInformationTransfer messages. This ensures that any critical information is not lost due to the failure.