The term encapsulation describes the process of putting headers and trailers around some data. A computer
that needs to send data encapsulates the data in headers of the correct format so that the receiving computer
will know how to interpret the received data. Data encapsulation with TCP/IP consists of five-steps:
Step 1: Create the application data and headers.
Step 2: Package the data for transport, which is performed by the transport layer (TCP or UDP). The
Transport Layer creates the transport header and places the data behind it.
Step 3: Add the destination and source network layer addresses to the data, which is performed by the
Inter network Layer. The Internetwork Layer creates the network header, which includes the network
layer addresses, and places the data behind it.
Step 4: Add the destination and source data link layer addresses to the data, which is performed by the
Network Interface Layer. The Network Interface Layer creates the data link header, places the data
behind it, and places the data link trailer at the end.
Step 5: Transmit the bits, which is performed by the Network Interface Layer. The Network Interface
Layer encodes a signal onto the medium to transmit the frame.