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The TCP/IP reference model

13 January, 2015 - 13:02

In contrast with OSI, the TCP/IP community did not spend a lot of effort defining a detailed reference model; in fact, the goals of the Internet architecture were only documented after TCP/IP had been deployed [Clark88]. 1122, which defines the requirements for Internet hosts, mentions four different layers. Starting from the top, these are :

  • an Application layer
  • a Transport layer
  • an Internet layer which is equivalent to the network layer of our reference model
  • a Link layer which combines the functionalities of the physical and datalink layers of our five-layer reference model

Besides this difference in the lower layers, the TCP/IP reference model is very close to the five layers that we use throughout this document.