Certified Information Systems Security Professional (CISSP) Practice Exam

Which layer of the OSI model is responsible for local area network communication?

1. Layer 1

2. Layer 2

3. Layer 3

4. Layer 4

The correct answer is: Layer 2

The correct response is associated with Layer 2 of the OSI model, which is specifically designed for data link layer operations. This layer is responsible for node-to-node data transfer and managing how data packets are placed on the network. It ensures that frames are transmitted over the physical layer and establishes a direct communication link between devices on the same local area network (LAN), identifying each device with MAC addresses. Layer 2 handles several crucial functions such as framing, addressing, and error detection/correction, thus facilitating reliable communication within a LAN environment. It assists in controlling how devices on a network communicate with each other, dealing with issues like collision detection and network traffic management. In contrast, Layer 1 pertains to the physical layer, which involves the actual physical connections and transmission medium, such as cables and switches. Layer 3 is focused on network layer functionalities, including routing data between different networks and adding logical addressing like IP addresses. Layer 4, as the transport layer, is concerned with end-to-end communication and error recovery but does not directly manage local communication issues or be involved in the specifics of local area network operations.