Physical Layer
Physical Layer in Computer Network
The physical layer is the first and lowest layer of the Open System Interconnection Model (OSI Model). The physical layer deals with bit-level transmission between different devices and supports electrical or mechanical interfaces connecting to the physical medium for synchronized communication. The main functionality of the physical layer is to transmit the individual bits from one node to another node.
Working for Physical Layer
Physical Layer is responsible for the actual physical connection between the devices. The physical layer contains information in the form of bits. It is responsible for transmitting individual bits from one node to the next. When receiving data, this layer will get the signal received and convert it into 0s and 1s and send them to the Data Link layer, which will put the frame back together.
Examples of protocols that use physical layers include
- Digital Subscriber Line
- Integrated Services Digital Network
- Infrared Data Association
- Universal Serial Bus
- Bluetooth
- Controller Area Network
- Ethernet
Functions of a Physical layer
- Line Configuration: It defines the way how two or more devices can be connected physically.
- Data Rate:: This layer defines the rate of transmission which is the number of bits per second.
- Representation of Bits: Data in this layer consists of stream of bits. The bits must be encoded into signals for transmission. It defines the type of encoding i.e. how 0's and 1's are changed to signal.
- Synchronization: Physical Layer deals with the synchronization of the transmitter and receiver. The sender and receiver are synchronized at bit level..
- Data Transmission: It defines the transmission mode whether it is simplex, half-duplex or full-duplex mode between the two devices on the network.
- Interface: The physical layer defines the transmission interface between devices and transmission medium.
- Topology: It defines the way how network devices are arranged.
- Signals: It determines the type of the signal used for transmitting the information.
- Transmission Modes: Physical Layer defines the direction of transmission between two devices: Simplex, Half Duplex, Full Duplex.