The Internet Protocol Suite is the set of communications protocols used for the Internet and other similar networks. It is commonly also known as TCP/IP named from two of the most important protocols in it: the Transmission Control Protocol (TCP) and the Internet Protocol (IP), which were the first two networking protocols defined in this standard. Modern IP networking represents a synthesis of several developments that began to evolve in the 1960s and 1970s, namely the Internet and local area networks, which emerged during the 1980s, together with the advent of the World Wide Web in the early 1990s. The Internet Protocol Suite consists of four abstraction layers. From the lowest to the highest layer, these are the Link Layer, the Internet Layer, the Transport Layer, and the Application Layer. The layers define the operational scope or reach of the protocols in each layer, reflected loosely in the layer names. Each layer has functionality that solves a set of problems relevant in its scope. The Link Layer contains communication technologies for the local network the host is connected to directly, the link. It provides the basic connectivity functions interacting with the networking hardware of the computer and the associated management of interface-to-interface messaging. The Internet Layer provides communication methods between multiple links of a computer and facilitates the interconnection of networks. As such, this layer establishes the Internet. It contains primarily the Internet Protocol, which defines the fundamental addressing namespaces, Internet Protocol Version 4 (IPv4) and Internet Protocol Version 6 (IPv6) used to identify and locate hosts on the network. Direct host-to-host communication tasks are handled in the Transport Layer, which provides a general framework to transmit data between hosts using protocols like the Transmission Control Protocol and the User Datagram Protocol (UDP). Finally, the highest-level Application Layer contains all protocols that are defined each specifically for the functioning of the vast array of data communications services. This layer handles application-based interaction on a process-to-process level between communicating Internet hosts. Contents [hide]
2 Layers in the Internet Protocol Suite
2.1 The concept of layers
2.2 Layer names and number of layers in the literature
4 See also
6 Further reading
7 External links
The Internet Protocol Suite resulted from research and development conducted by the Defense Advanced Research Projects Agency (DARPA) in the early 1970s. After initiating the pioneering ARPANET in 1969, DARPA started work on a number of other data transmission technologies. In 1972, Robert E. Kahn joined the DARPA Information Processing Technology Office, where he worked on both satellite packet networks and ground-based radio packet networks, and recognized the value of being able to communicate across both. In the spring of 1973, Vinton Cerf, the developer of the existing ARPANET Network Control Program (NCP) protocol, joined Kahn to work on open-architecture interconnection models with the goal of designing the next protocol generation for the ARPANET. By the summer of 1973, Kahn and Cerf had worked out a fundamental reformulation, where the differences between network protocols were hidden by using a common internetwork protocol, and, instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible. Cerf credits Hubert Zimmerman and Louis Pouzin, designer of the CYCLADES network, with important influences on this design. The network's design included the recognition it should provide only the functions of efficiently transmitting and routing traffic between end nodes and that all other intelligence should be located at the edge of the network, in the end nodes. Using a simple design, it became possible to connect almost any network to the ARPANET,...