iSACA Cybersecurity Fundamentals Certification Practice Exam

What does the "Physical Layer" of the OSI model manage?

1. Data encryption and decryption

2. Signal transmission among network systems

3. User connection management

4. Data sequencing and reliability

The correct answer is: Signal transmission among network systems

The Physical Layer of the OSI model is primarily responsible for the transmission and reception of raw data bits over a physical medium. This means it deals with the actual signals that are sent across the network, including the electrical, optical, or radio signals that convey data. This layer defines the physical characteristics of the network hardware, such as cables, switches, and any other device that transmits data through a medium. Signal transmission encompasses various aspects, including the type of signaling (e.g., analog or digital), voltage levels, timing of signal changes, and the physical connectors used. Since its core function is to manage these physical transmission aspects, this layer ensures that the transmitted data can be successfully received by the receiving end. In contrast, the other aspects mentioned in the other choices focus on different layers of the OSI model. For instance, data encryption and decryption pertain to security protocols found in higher layers, while user connection management and data sequencing relate more to the Transport Layer, which oversees the reliability and integrity of the data being transmitted.