Question: In a Point-to-Point Short Message Service (SMS) on a mobile radio interface, what is the primary purpose of a Transaction Identifier in Short Message Control (SMC) procedures?
Option 1: To prioritize RP Data Unit (RPDU) transfers based on message urgency
Option 2: To authenticate the sender's identity for security purposes
Option 3: To manage concurrent connections with multiple SMC entities
Option 4: To identify and isolate instances of an SMC entity, ensuring messages are treated only by the corresponding instance
Explanation: The correct answer is because Transaction Identifiers differentiate between various instances of an SMC entity, ensuring each entity only processes messages specifically addressed to it, preventing confusion or mismanagement of messages across different entities.