The physical layer is the first layer in the OSI model that deals with the physical transmission medium. The data transferred via the physical layer is in the form of electrical signals.
In real life, we can treat the physical layer as the road where the vehicles are passing. There is a reason why I chose the road to explain the Physical Layer. The road is the one which is carrying the vehicles and linking the cities.
The physical layer is the lowest layer in the OSI Reference Model.
Like that example, the physical layer transmits the data signal in electrical signals and connecting nodes.
We can consider the road as the physical layer and vehicles as the electric signals. Just replace the city with a node. I guess you understand the concept.
The major cables using in physical layer
The physical layer is all about the connections. So, which cables do we use in this layer to form a network?
Coaxial cable
Twisted pair cable
Optical fiber cable
Devices Working in the Physical Layer
Sometimes, interviewers may ask about the devices working in the physical layer. They are:
Internet gateway
Hub
Repeater
The Functions and Services Performed by the Physical Layer are:
1. Bit-by-bit delivery
2. Modulation
3. Encoding and Signaling:
4. Bit synchronization
5. Physical Network Topology
In the Physical Layer, data flows in the form of an electric pulse, and the cables are responsible for the safe delivery of the signals. The physical layer is responsible for varying the waveform for the data transfer. This process is known as modulation.
The physical layer is also responsible for various types of encoding and decoding of signals.
The physical layer cares about the transmission mode. It is also the physical layout of the network( topology).
The seven layer structure of the OSI Reference Model is:
