iSACA Cybersecurity Fundamentals Certification Practice Exam

What is the role of the "Transport Layer" in the OSI model?

1. To ensure applications can communicate

2. To break data into frames

3. To ensure that data are transferred reliably in the correct sequence

4. To manage physical connections between devices

The correct answer is: To ensure that data are transferred reliably in the correct sequence

The Transport Layer of the OSI model is crucial for providing reliable end-to-end communication between devices across a network. Its primary role is to ensure that data is transferred reliably and in the correct sequence. This is achieved through various mechanisms, including error detection and correction, acknowledgments, and retransmission of lost or corrupted packets. When a sender transmits data, the Transport Layer breaks it down into segments, adding necessary headers that include sequence numbers and error-checking information. This allows the receiving device to reassemble the data in the correct order and verify its integrity, ensuring a consistent and accurate communication process. The importance of this layer lies in its ability to provide reliability and manage the flow of data, which is essential for applications that require a stable connection and precision, such as file transfers or video streaming. The Transport Layer employs different protocols, such as TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), catering to applications based on their specific needs for reliability and speed. In contrast, the roles of other layers involve different responsibilities: ensuring application communication pertains to the Application Layer, breaking data into frames is a function of the Data Link Layer, and managing physical connections is assigned to the Physical Layer. Each layer in the OSI model has