Palo Alto Networks (PANW) Certified Cybersecurity Entry-level Technician (PCCET) Practice Exam

Which layer in the OSI model is responsible for end-to-end communication and data integrity?

1. Physical layer

2. Transport layer

3. Network layer

4. Application layer

The correct answer is: Transport layer

The Transport layer of the OSI model is crucial for enabling end-to-end communication between devices on a network. This layer is responsible for ensuring that data is delivered accurately and in the correct sequence from the source to the destination. It achieves this through various protocols, such as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). One of the key functions of the Transport layer is to manage data segmentation, which involves breaking down larger messages into smaller packets for transmission and then reassembling them at the receiving end. Additionally, it provides error detection and recovery, ensuring data integrity by verifying that the data received is complete and correct. If any packets are lost or corrupted during transmission, the Transport layer can request retransmission of those packets. By focusing on both the integrity of the data being transmitted and the management of communication sessions, the Transport layer effectively fulfills its role in the OSI model, distinguishing itself from the other layers which have different functions, such as routing, signal transmission, or providing application-level services.