Internet Fundamentals: The Global Network of Networks

The Internet is a massive, global system of interconnected computer networks. Rather than being a single entity, it is a "network of networks" that links private, public, academic, business, and government networks across the globe. By utilizing the Internet protocol suite (TCP/IP), these diverse networks communicate seamlessly using electronic, wireless, and optical technologies.

While often used interchangeably with the World Wide Web, the two are distinct. The Internet is the underlying infrastructure, whereas the World Wide Web (WWW) is a service that uses the Internet to access interlinked hypertext documents and applications via URLs. Beyond the web, the Internet supports a vast array of services, including electronic mail, internet telephony, streaming media, file sharing, and instant messaging.

: A sketch of the ARPANET in December 1969. The nodes 1-4, and computers: SDS Sigma 7 at UCLA, SDS 940 at Stanford Research Institute (SRI), IBM 360/75 at UCSB and the PDP-10 at University of Utah are depicted.[17]

Key Facts

Banner in Bangkok during the 2014 Thai coup d'état, informing the Thai public that 'like' or 'share' activities on social media could result in imprisonment (observed 30 June 2014)

The Internet relies on the TCP/IP protocol suite for communication.
It encompasses local to global networks through various physical media.
The World Wide Web is a specific application that runs on the Internet.
Global connectivity is managed through various regional registries and organizations like ICANN.

The Evolution of Connectivity

This NeXT Computer was used by Tim Berners-Lee at CERN and became the world's first Web server.

The foundations of the modern Internet can be traced back to early networking experiments. The transition from specialized research networks to a global utility has transformed nearly every aspect of human communication, from traditional print media and telephone services to digital newspapers, online shopping, and social networking.

Historical Milestones

The journey from the early days of ARPANET to the modern era has seen exponential growth in both users and technology. As connectivity moved from academic circles into the mainstream, the infrastructure evolved from simple node connections to complex submarine fiberoptic cables and high-speed backbone networks.

: T3 NSFNET Backbone, c. 1992

The rise of mobile communication has further accelerated this growth, allowing users to access the network from virtually anywhere. This shift has fundamentally changed how businesses operate, affecting supply chains and enabling financial services to function on a global scale.

: Number of mobile cellular subscriptions 2012–2016

Internet Infrastructure and Protocols

Packet routing across the Internet involves several tiers of Internet service providers.

To function, the Internet requires a standardized way for devices to identify one another and route data. This is achieved through IP addresses, which are unique identifiers for devices on a network. Currently, the world uses IPv4, though the industry is transitioning to IPv6 to accommodate the growing number of connected devices.

: As user data is processed through the protocol stack, each abstraction layer adds encapsulation information at the sending host. Data is transmitted over the wire at the link level between hosts and routers. Encapsulation is removed by the receiving host. Intermediate relays update link encapsulation at each hop, and inspect the IP layer for routing purposes.

Routing and Addressing

Data travels across the Internet through a process called routing. This involves several tiers of Internet service providers (ISPs) that direct packets of data toward their destination. To make the network user-friendly, the Domain Name System (DNS) translates human-readable domain names (like wikipedia.org) into the numerical IP addresses that computers use to locate each other.

: A DNS resolver consults three name servers to resolve the domain name user-visible "www.wikipedia.org" to determine the IPv4 Address 207.142.131.234.

: Creating a subnet by dividing the host identifier

The physical backbone of this system includes massive undersea cables that connect continents, ensuring that data can move across oceans at high speeds.

: 2007 map showing submarine fiberoptic telecommunication cables around the world

Global Usage and Trends

Conceptual data flow in a simple network topology of two hosts (A and B) connected by a link between their respective routers. The application on each host executes read and write operations as if the processes were directly connected to each other by some kind of data pipe. After the establishment of this pipe, most details of the communication are hidden from each process, as the underlying principles of communication are implemented in the lower protocol layers.

The adoption of the Internet varies significantly by region and economic development. While developed nations see very high rates of connectivity, developing regions are experiencing rapid growth, driven largely by mobile technology.

Comparison of Internet Usage Trends
Metric	Worldwide	Developing World	Developed World
Usage Share (Historical/Sample)	Variable	Lower baseline	Higher baseline
Growth Drivers	Mobile/Broadband	Mobile expansion	High-speed fiber/5G

: Share of population using the Internet.[75] Source data.

A scatter plot showing Internet usage per capita versus GDP per capita. It shows Internet usage increasing with GDP. — Internet users per 100 population members and GDP per capita for selected countries

: Internet users per 100 population members and GDP per capita for selected countries

: Internet users per 100 inhabitantsSource: International Telecommunication Union.[76][77]

: Source: Our World in Data.

: Source: International Telecommunication Union.[94]

: Source: International Telecommunication Union.[95]

Governance and Management

Pervasive Substantial Selective Little or none Unclassified / No data

Because the Internet is a global resource, its management involves several specialized organizations. ICANN (Internet Corporation for Assigned Names and Numbers) plays a critical role in coordinating the Internet's unique identifiers. Additionally, Regional Internet Registries (RIRs) manage IP address allocation for specific parts of the world:

AfriNIC: Africa
ARIN: North America
APNIC: Asia and the Pacific
LACNIC: Latin America and the Caribbean

: ICANN headquarters in the Playa Vista neighborhood of Los Angeles, California, United States

Frequently Asked Questions

What is the difference between the Internet and the World Wide Web?

The Internet is the massive hardware and software infrastructure of interconnected networks. The World Wide Web is a service that runs on top of that infrastructure, consisting of the pages and documents we access via web browsers.

How does my computer find a website?

Your computer uses the Domain Name System (DNS), which acts like a phonebook for the Internet, converting a website name into a numerical IP address that your computer can understand.

What are IP addresses?

An IP address is a unique numerical label assigned to every device connected to a computer network. It serves two main functions: host or network interface identification and location addressing.

Why is the world moving from IPv4 to IPv6?

IPv4 uses a 32-bit addressing scheme, which provides a limited number of unique addresses. As billions of new devices connect to the Internet, we are running out of IPv4 addresses, making the larger 128-bit IPv6 system necessary.

What is packet routing?

Packet routing is the process of selecting paths in a network along which to send network traffic. Data is broken into small chunks called packets, which are then sent through various routers and service providers until they reach their destination.