Question: When decoding RRC message PDUs containing BIT STRING or OCTET STRING with ASN.1 Contents Constraint ("CONTAINING"), what is the recommended approach to handle potential errors in the contained type?
Option 1: Automatically decode the contained type, and if errors occur, discard the entire RRC message PDU.
Option 2: Decode the outer PDU type first, then separately decode the contained type nested within, to isolate decoding errors.
Option 3: Report an error if there are extraneous bits at the end of the encoded BIT STRING or OCTET STRING.
Option 4: Ignore all Contents Constraints and proceed with automatic decoding of the entire RRC message PDU.
Explanation: This approach ensures that errors in decoding the contained type do not cause the entire RRC message PDU to fail, maintaining robustness in the decoding process. It aligns with the recommendation for handling Contents Constraints in RRC protocol specifications, prioritizing the successful decoding of the outer PDU before attempting to decode nested types.