Question: What is the primary purpose of the message sequence numbering scheme in the data link layer of the Iuant interface?
Option 1: To prioritize messages based on their content
Option 2: To manage flow control between devices
Option 3: To enhance encryption for secure transmission
Option 4: To protect against duplicated, deleted, or out-of-order messages at Layer 7
Explanation: The message sequence numbering scheme is crucial for maintaining the integrity of message exchange between devices. By sequencing messages, the data link layer can detect and correct errors such as duplicate transmissions, lost (deleted) messages, or messages received out of their intended order, thereby safeguarding the reliability of communication at Layer 7 (the Application Layer), where services and interfaces are directly exposed to the user or applications.