Question 1: Explain the purpose of the Physical layer in a computer network.

Answer: The Physical layer is responsible for transmitting raw bits over a physical medium, such as cables or wireless signals, ensuring the physical connection between devices.

Question 2: Describe the main function of the Data Link layer in network communication.

Answer: The Data Link layer manages node-to-node data transfer, error detection, and flow control to ensure reliable data transfer over the physical link.

Question 3: List the three primary functions of the Network layer.

Answer: Routing data packets between devices, logical addressing (such as IP addresses), and packet forwarding.

Question 4: Identify which layer is responsible for establishing end-to-end communication between applications.

Answer: The Transport layer.

Question 5: Describe the role of the Application layer in network communication.

Answer: The Application layer provides network services directly to user applications, such as email, file transfer, and web browsing.

Question 6: Imagine a scenario where a web browser requests a webpage. Trace the data flow through the layers from the application to the physical medium, describing each step briefly.

Answer: The request starts at the Application layer (web browser). It passes to the Transport layer (TCP), then to the Network layer (IP routing), followed by the Data Link layer (frame creation), and finally transmitted via the Physical layer as electrical or optical signals over cables or wireless medium.

Question 7: Complete the following truth table for an AND gate: | Input A | Input B | Output | |---------|---------|---------| | 0 | 0 | | | 0 | 1 | | | 1 | 0 | | | 1 | 1 | |

Answer: 0, 0, 0; 0, 1, 0; 1, 0, 0; 1, 1, 1.

Question 8: Sketch a simple diagram illustrating the relationship between the seven layers of the OSI model. Label each layer clearly.

Answer: A vertical stack of seven horizontal layers, from bottom to top: Physical, Data Link, Network, Transport, Session, Presentation, Application. Each layer should be labeled accordingly and connected to the adjacent layers.

Question 9: Describe how data is encapsulated as it moves down the layers in a network device before transmission.

Answer: At each layer, additional headers (and sometimes trailers) are added to the data to provide necessary information for handling, routing, and error checking. This process is called encapsulation, and it continues until the data is converted into signals suitable for transmission.

Question 10: Explain why multiple layers are necessary in a network protocol stack instead of having a single, all-encompassing layer.

Answer: Multiple layers allow for modular design, making systems easier to develop, troubleshoot, and update. Each layer handles specific functions, enabling interoperability and flexibility across different hardware and software.