Question: What is the primary purpose of the Short Message Identifier (SMI) in the interaction between the Short Message Application Layer (SM-AL) and the Short Message Transfer Layer (SM-TL)?
Option 1: To authenticate the sender of short messages
Option 2: To compress short message data for efficient transfer
Option 3: To track messages and their associated reports across layers
Option 4: To prioritize the delivery of certain short messages over others
Explanation: The Short Message Identifier (SMI) serves as a reference number, enabling the tracking of messages and their corresponding reports as they are transferred between the SM-AL and SM-TL. This facilitates efficient management and processing of short messages within the telecom network, ensuring that each message can be uniquely identified and its status updates accurately communicated.