Encapsulation (networking)

Encapsulation is the computer-networking process of concatenating layer-specific headers or trailers with a service data unit (i.e. a payload) for transmitting information over computer networks.

[2][3][4] Deencapsulation (or de-encapsulation) is the reverse computer-networking process for receiving information; it removes from the protocol data unit (PDU) a previously concatenated header or tailer that an underlying communications layer transmitted.

[2][4] These two processes are common features of the computer-networking models and protocol suites, like in the OSI model and internet protocol suite.

[3] However, encapsulation/deencapsulation processes can also serve as malicious features like in the tunneling protocols.

[6] The physical layer is responsible for physical transmission of the data, link encapsulation allows local area networking, IP provides global addressing of individual computers, and TCP selects the process or application (i.e., the TCP or UDP port) that specifies the service such as a Web or TFTP server.

Encapsulation of user data in the Unix -style UDP stack, in which each new layer includes the data from the previous layer, but without being able to identify which part of the data is the header or trailer from the previous layer. This effectively hides (encapsulates) the information from lower layers. [ 1 ]