ISO Connectionless Network Service

The International Organization for Standardization (ISO), currently known as the International Telecommunications Union (ITU), laid the foundation for standardization of computer networking by defining the seven-layer OSI reference model (see Figure 2-1). The OSI reference model, also known as the OSI stack, is specified in ISO 7498. (The ISO standards documents cited in this chapter can be found at

Figure 2-1. The OSI reference model.

The OSI reference model is a significant contribution to the foundations and subsequent evolution of data communications and information technology. It provides the ...

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