Question: In UTRAN Iu-BC interface's Service Area Broadcast Protocol (SABP), what happens if a received SABP message does not adhere to the specified ASN.1 structure and content rules, such as incorrect ordering or occurrence of Information Elements (IEs)?
Option 1: The message is ignored but an acknowledgement is sent to the sender.
Option 2: The receiving entity attempts to correct the syntax error before processing.
Option 3: The message is processed with available valid IEs, ignoring the erroneous parts.
Option 4: The message is considered as an Abstract Syntax Error and handled according to predefined error handling procedures.
Explanation: If a received SABP message does not conform to the specified ASN.1 structure, it is treated as an Abstract Syntax Error. In such cases, the protocol dictates handling the error in a predefined manner, ensuring consistency and reliability in network communications, preventing potential misinterpretations or system vulnerabilities from improperly formatted messages.