Each and every layer has some identity in the network communication . when the devices are communicating over the network, Each and every layer are going to treat those data separately according to their own job.
Each layer adds some additional bits into the packet for the identity of the layer.
Now let’s see it.
Encapsulation: As each layer receives a PDU from the layer above it, headers are added.
Decapsulation: As each layer receives a PDU from the layer below it, headers are inspected and then removed.
When the data is carried in the physical cable as electric energy the receiver end NIC is going to convert those electric signals into 0 and 1 . And then in the receiver end, each and every layer is going to strip off their information and only represent the data. That’s called encapsulation and decapsulation.
PDU Transportation & Recognition.
In the networking model, the terms encapsulation and de-encapsulation refer to a process in which protocol information is added to and removed from the data as it passes through the layers.
Protocol information can be added before and after the data. If information is added before the data, it is called a header. If information is added after the data, it is called a trailer.
The header and end added by a layer in the sending computer can only be deleted by the peer layer of the receiving computer. For example, the header and end added by the transport layer in the sending computer can only be deleted by the transport layer in the receiving computer.
When data encapsulated by a layer on the sending computer is processed by the same layer on the receiving computer, it is called the same layer interaction.
The encapsulation process takes place in the sending computer while the de-encapsulation process takes place in the receiving computer. After encapsulation, each layer uses a specific name or term to represent the encapsulated data.