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 Information is an Abstraction, abstract concept that refers to something which has the power Communication, to inform. At the most fundamental level, it pertains to the Interpretation (philosophy), interpretation (perhaps Interpretation (log ...

over computer networks. 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 trailer that an underlying communications layer transmitted. Encapsulation and deencapsulation allow the design of modular communication protocols so to logically separate the function of each communications layer, and abstract the structure of the communicated information over the other communications layers. These two processes are common features of the computer-networking models and protocol suites, like in the

OSI model The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems inter ...

and

internet protocol suite The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

. However, encapsulation/deencapsulation processes can also serve as malicious features like in the tunneling protocols.Raman, D., Sutter, B. D., Coppens, B., Volckaert, S., Bosschere, K. D., Danhieux, P., & Buggenhout, E. V. (2012, November). DNS tunneling for network penetration. In International Conference on Information Security and Cryptology (pp. 65-77). Springer, Berlin, Heidelberg. The

physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer: the layer most closely associated with the physical connection between devices. The physical layer provides an electrical, mechani ...

is responsible for physical transmission of the data, link encapsulation allows

local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of da ...

ing, 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. For example, in the IP suite, the contents of a web page are encapsulated with an HTTP header, then by a TCP header, an IP header, and, finally, by a frame header and trailer. The frame is forwarded to the destination node as a

stream A stream is a continuous body of water, body of surface water Current (stream), flowing within the stream bed, bed and bank (geography), banks of a channel (geography), channel. Depending on its location or certain characteristics, a strea ...

of bits, where it is decapsulated into the respective PDUs and interpreted at each layer by the receiving node. The result of encapsulation is that each lower-layer provides a service to the layer or layers above it, while at the same time each layer communicates with its corresponding layer on the receiving node. These are known as adjacent-layer interaction and same-layer interaction, respectively. In discussions of encapsulation, the more abstract layer is often called the upper-layer protocol while the more specific layer is called the lower-layer protocol. Sometimes, however, the terms upper-layer protocols and lower-layer protocols are used to describe the layers above and below IP.

References

External links

*{{IETF RFC, 1983: Internet Users' Glossary (contains an entry for encapsulation) Computer network technology Network protocols Data transmission Packets (information technology)

See also

References

External links