What are the key features of the OSI Model's Physical layer?

The Physical layer is the first layer of the OSI Model and is responsible for the transmission and reception of raw bit streams over a physical medium. The key features of the Physical layer are as follows:

1. Transmission of bits: The Physical layer converts the digital data generated by the upper layers into a stream of bits for transmission over the physical medium. It defines the electrical, mechanical, and procedural characteristics required to physically transmit the bits.

2. Physical medium: It defines the types of physical media that can be used for communication, such as copper wires, fiber-optic cables, or wireless transmission. Each type of medium has its own characteristics, including bandwidth, transmission speed, and distance limitations.

3. Data encoding: The Physical layer determines how the bits are encoded into signals that can be transmitted over the physical medium. It includes techniques like modulation, which converts digital signals into analog signals suitable for transmission.

4. Signal transmission: The Physical layer handles the actual transmission of signals over the physical medium. It defines the rules for signal timing, voltage levels, and signal synchronization to ensure reliable transmission.

5. Physical addressing: It defines the physical addressing scheme used to identify devices on the network. This can include MAC addresses for Ethernet networks or physical addresses for other types of networks.

6. Bit synchronization: The Physical layer ensures that the sender and receiver are synchronized in terms of bit timing. It establishes the start and end of each bit, allowing the receiver to correctly interpret the transmitted data.

7. Error detection and correction: The Physical layer may include mechanisms for error detection and correction to ensure data integrity during transmission. This can involve techniques like parity checking or checksums.

Overall, the Physical layer focuses on the physical aspects of communication, ensuring that the bits are transmitted reliably over the physical medium.