Explain the concept of data encapsulation.

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 Solution :-

  • In computer networking, the term encapsulation is used to refer to the process of each layer at the sending computer adding its own header information, in the form of meta-data to the actual payload (data) 
  • To satisfy all the requirements, the protocols operating at the various layers work together to supply a unified quality of service.
  • In a typical transaction, an application layer protocol (which includes presentation and session layer functions) generates a message that is passed down to a transport layer protocol.
  • The protocol at the transport layer has its own packet structure, which is known as a protocol data unit (PDU).
  • PDU includes specialized header field and a data field that carries the payload.
  • The payload is the data received from the application layer protocol.
  • The transport layer encapsulates the application layer data and then passes it down to the next layer.
  • The network layer protocol then receives the PDU from the transport layer and encapsulates it within its own PDU by adding a header and using the entire transport layer PDU as its Payload.
  • The same process occurs again when the network layer passes its PDU to the data link layer, which adds a header and footer.
  • Once it is encapsulated by the data link protocol, the complete packet is then ready to be converted to the appropriate type of signal used by the network medium.T
  • The final packet consists of original application layer data plus several headers added by the protocol at the succeeding layers.

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