TCP/IP model: Difference between revisions

Revision as of 03:27, 25 March 2012

Revision as of 06:37, 26 March 2012

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These textbooks are secondary sources that may contravene the intent of RFC 1122 and other IETF primary sources such as RFC 3439.<ref name=R3439 />

Different authors have interpreted the RFCs differently regarding the question whether the Link Layer (and the TCP/IP model) covers [[Physical Layer]] issues, or whether the hardware layer is outside the scope of TCP/IP. Some authors have tried to use other names for the Link Layer, such as ''network interface layer'', in viewan effort to avoid confusion with the [[Data Link Layer]] of the seven-layer [[OSI model]]. Others have attempted to map the Internet Protocol model onto the OSI Model. The mapping sometimes results in a hybrid model with five layers where the Link Layer is split into a Data Link Layer on top of a physical layer. In literature with a bottom-up approach to Internet communication,<ref name=Forouzan/><ref name=Comer/><ref name=Stallings/> in which hardware issues are emphasized, those are often discussed in terms of the OSI model.

The Internet Layer is usually directly mapped into the OSI Model's [[Network Layer]], a more general concept of network functionality. The Transport Layer of the TCP/IP model, which may be described as a host-to-host layer, is mapped to OSI Layer 4 (Transport Layer), sometimes also including aspects of OSI Layer 5 ([[Session Layer]]) functionality. OSI's [[Application Layer]], [[Presentation Layer]], and the remaining functionality of the Session Layer are collapsed into TCP/IP's Application Layer. The argument is that these OSI layers do usually not exist as separate processes and protocols in Internet applications.{{Citation needed|date=April 2009}}