# Internet Protocol

The Internet is composed of hardware infrastructure and software infrastructure. The hardware infrastructure consists of client computers, routers, and [critical Internet infrastructure](https://en.wikipedia.org/wiki/Critical_Internet_infrastructure) (routers, ISP access hubs, fiber optic cables, switches, satellites and submarine cables of the backbone network, etc.). Software infrastructure consists of [communication protocols](https://en.wikipedia.org/wiki/Internet_Protocol), [domain name systems](https://en.wikipedia.org/wiki/Domain_Name_System), login systems, [data centers](https://en.wikipedia.org/wiki/Data_center), etc.

[**OSI model**](https://en.wikipedia.org/wiki/OSI_model)

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The model partitions the flow of data in a communication system into seven [abstraction layers](https://en.wikipedia.org/wiki/Abstraction_layer) to describe networked communication from the physical implementation of transmitting [bits](https://en.wikipedia.org/wiki/Bit) across a [communications medium](https://en.wikipedia.org/wiki/Transmission_medium) to the highest-level representation of data of a [distributed application](https://en.wikipedia.org/wiki/Distributed_application). Each intermediate layer serves a class of functionality to the layer above it and is served by the layer below it. Classes of functionality are realized in all software development through all standardized [communication protocols](https://en.wikipedia.org/wiki/Communication_protocol).

The two major international organizations that play a major role in formulating [computer network](https://en.wikipedia.org/wiki/Computer_network) standards are: International Telecommunication Union Telecommunication Standardization Sector ([ITU-T](https://en.wikipedia.org/wiki/ITU-T)) and the International Standards Organization ([ISO](https://en.wikipedia.org/wiki/International_Organization_for_Standardization)). These standards allow computers of different types and operating systems around the world to communicate with each other.