History of Computer Networking

History of Computer Networking: From Early Connections to the Modern Internet

Early Innovations and Pre-Internet Networks

The idea of connecting computing devices predates the Internet. One early milestone occurred in 1940 when Bell Labs researcher George Stibitz demonstrated remote computing: he connected a teleprinter terminal at Dartmouth College to his Complex Number Calculator in New York over phone lines en.wikipedia.org. This was perhaps the first instance of a computer network, showing that computers could communicate across distance. During the 1950s, telephone lines and modems began to be used for data – AT&T’s Bell 101 modem (1958) could transmit digital data at 110 bits/s over ordinary phone circuits en.wikipedia.org. The existing communication networks (telegraph and telephone) laid groundwork by proving that signals could be relayed globally; however, early computers were mostly isolated, with limited ability to communicate with each other.

By the late 1950s, large-scale military networks emerged. A landmark was the U.S. Air Force’s SAGE (Semi-Automatic Ground Environment) system, completed in 1958. SAGE linked 23 computerized radar centers across North America in real time, creating a network to track potential bomber attacks computerhistory.org computerhistory.org. This networked air-defense system was built using phone lines and primitive modems, pioneering the concept of interactive, multi-site computer communication. Another early network was SABRE, an airline reservation system developed by IBM for American Airlines. Deployed in 1964, SABRE connected terminals in 65 cities to IBM mainframes via telephone lines, allowing remote booking transactions in seconds computerhistory.org computerhistory.org. These pre-Internet systems were specialized but proved the feasibility and value of connecting computers for a common purpose. By the 1960s, visionary computer scientists like J.C.R. Licklider were articulating dreams of an “Intergalactic Computer Network” — a globally interconnected set of computers through which everyone could quickly access data and programs computerhistory.org. Licklider’s ideas, along with the advent of time-sharing (multiple users sharing one computer via terminals), set the stage for true computer networking computerhistory.org computerhistory.org.

ARPANET and the Birth of Packet Switching

In the 1960s, researchers developed a new data communication paradigm called packet switching – a revolutionary alternative to traditional circuit-based communications. Paul Baran at RAND (USA) and Donald Davies at NPL (UK) independently invented the concept of packet switching for digital networks en.wikipedia.org. Instead of holding open a dedicated circuit for the whole conversation (as telephone networks did), packet-switching breaks data into small blocks (packets) sent independently across a network and reassembled at the destination. This approach made networks robust (packets can be rerouted around failures) and efficient in using bandwidth en.wikipedia.org. Davies built a packet-switching prototype at the UK’s National Physical Laboratory by 1968, achieving a high-speed local network of 768 kb/s en.wikipedia.org. Baran’s work for a distributed, survivable network and Davies’ research both heavily influenced the next major project in networking en.wikipedia.org en.wikipedia.org.

ARPANET, created by the U.S. Advanced Research Projects Agency (ARPA), was the first large-scale packet-switching computer network. ARPA (later DARPA) initiated the project in 1966 under program manager Larry Roberts with a vision to connect time-sharing computers at research universities. The contract to build ARPANET’s switching nodes (called Interface Message Processors or IMPs) was awarded to BBN Technologies in 1968 en.wikipedia.org en.wikipedia.org. The network’s design was guided by many pioneers: Leonard Kleinrock provided mathematical queuing theory to ensure packet-switching efficiency, Wesley Clark proposed using smaller IMP computers as network switches, and Frank Heart led the BBN engineering team en.wikipedia.org en.wikipedia.org.

ARPANET’s first node was installed at UCLA in September 1969, and by October 1969 the first message was sent to the Stanford Research Institute (SRI). By the end of 1969, four sites (UCLA, SRI, UC Santa Barbara, and University of Utah) were connected at 50 kb/s en.wikipedia.org. Notably, the first transmitted text was “LOGIN”, though only the letters “LO” were received before the system crashed – a humble beginning of networked communication. October 29, 1969 is often celebrated as ARPANET’s birthday.

A map of ARPANET in the early 1970s, showing nodes (universities and research labs) and the lines connecting them. ARPANET was the first packet-switched network to connect heterogeneous computers over long distances computerhistory.org. Its success proved the viability of packet switching and laid the foundation for the Internet.

ARPANET rapidly expanded throughout the early 1970s. In 1971, the network grew to 15 nodes and enabled a “killer app”: email. Programmer Ray Tomlinson of BBN introduced network email in 1971 and chose the “@” symbol to separate user and host in addresses, a notation still used today computerhistory.org. Email traffic soon dominated ARPANET, accounting for a majority of packets by 1973 computerhistory.org. The network also fostered the first online communities and discussion forums. New nodes joined across the U.S., and international connections followed: a satellite link to Norway and a landline to London were added by 1973, making ARPANET the nucleus of a global network experiment en.wikipedia.org.

Crucially, ARPANET implemented packet switching at its core and proved its superiority for computer networking. Each IMP minicomputer would store incoming data packets and forward them to the next node, using dynamic routing. This distributed design had no single point of failure, which was initially of interest for survivability. (Although a popular myth suggested ARPANET was designed to survive nuclear attacks, its creators clarified that the goal was resource sharing among researchers, not military command-and-control en.wikipedia.org en.wikipedia.org.) Still, the decentralized, resilient architecture of ARPANET was a breakthrough. By demonstrating that computers of different kinds (mainframes from IBM, DEC, SDS, etc.) could communicate over a network of IMPs, ARPANET created a network of networks – the first incarnation of what would become the Internet computerhistory.org.

Internetworking: TCP/IP and the Internet Emerges (1970s–1980s)

By the mid-1970s, multiple packet-switched networks had appeared around the world. Besides ARPANET, there was Britain’s NPL network led by Donald Davies, France’s CYCLADES led by Louis Pouzin, and specialized networks like ALOHANET (a wireless packet radio network in Hawaii) computerhistory.org. Each network used its own protocols, which meant they couldn’t easily interconnect. This led to the next grand challenge: internetworking – connecting disparate networks into one coherent system. In 1973, ARPA’s researchers Vint Cerf and Bob Kahn began designing a unifying protocol to allow different networks to inter-network, giving birth to the set of rules that underpin the modern Internet computerhistory.org.

Cerf and Kahn’s solution was the Transmission Control Protocol/Internet Protocol (TCP/IP). They published a landmark paper in 1974 describing a “Protocol for Packet Network Intercommunication” en.wikipedia.org. TCP/IP splits networking tasks into layers: IP handles addressing and routing packets across networks, and TCP ensures reliable delivery (packets are acknowledged and reordered as needed). This modular design allowed any underlying network – ARPANET, radio networks, satellite links, etc. – to join a common “Internet” by using gateway machines speaking IP. Importantly, CYCLADES had influenced this model by insisting that reliability be handled end-to-end by the hosts rather than by the network core en.wikipedia.org. Adopting that end-to-end principle, TCP/IP made the network simpler and the hosts smarter.

Throughout the late 1970s, TCP/IP was refined through experimentation. ARPA funded tests connecting ARPANET with a Packet Radio Network (PRNET) and a satellite network (SATNET). In a famous 1977 demonstration, a van equipped with a packet radio transmitter drove through California and successfully sent a message through the packet radio network, into SATNET, then to ARPANET, reaching a computer in Europe computerhistory.org computerhistory.org. This end-to-end transmission over three networks proved the TCP/IP internetworking concept. By 1978, TCP was split into two protocols (TCP and IP as we know them), and implementation began on ARPANET hosts.

On January 1, 1983, often called “flag day”, ARPANET officially switched from its old Network Control Program (NCP) to TCP/IP – effectively creating the Internet as a standard protocol for all networks en.wikipedia.org. This date is considered the Internet’s birthdate by many historians usg.eduen.wikipedia.org. After 1983, any network that spoke TCP/IP could exchange data with any other, and ARPANET (now using TCP/IP) became the core of a growing Internet. ARPANET itself split that year: the military segment of ARPANET was separated into MILNET for security, while the civilian/research segment continued as ARPANET proper en.wikipedia.org. Over the rest of the 1980s, ARPANET’s role diminished as new backbone networks grew, and it was finally decommissioned in 1990. But the Internet – the network of networks – kept growing.

Parallel to the internetworking advances, the Domain Name System (DNS) was introduced in 1983 to map numeric IP addresses to human-friendly names (like mit.edu) en.wikipedia.org. Organizations like the Internet Engineering Task Force (IETF) formed to manage protocol standards. By 1986, the U.S. National Science Foundation created NSFNET, a high-speed backbone linking five supercomputing centers at 56 kb/s en.wikipedia.org. NSFNET soon upgraded to T1 (1.5 Mb/s) and became the main artery of the Internet, connecting an expanding web of regional and international academic networks. The late 1980s saw explosive growth: the number of Internet host computers passed 100,000 by 1989 computerhistory.org. At this time, the Internet was still used primarily by government and academia; commercial use was limited by policy. Competing networking architectures like the ISO’s OSI model were debated in standards bodies computerhistory.org, but TCP/IP’s free availability (bundled with UNIX) and proven track record gave it an edge computerhistory.org. By 1990, the Internet linked hundreds of thousands of computers worldwide, foreshadowing the imminent global connectivity boom.

Local and Global Networks in the 1970s–80s: LANs, WANs, and Commercial Systems

While ARPANET and the Internet evolved, there were other important networking developments, especially in local area networks (LANs) and commercial data networks. Early computer networks were mainly long-distance (ARPANET spanned the country), but computers also needed to communicate within offices or campuses at high speed. In 1973, researchers at Xerox PARC – Robert Metcalfe and David Boggs – invented Ethernet, a landmark LAN technology computerhistory.org. Ethernet used a simple “shared medium” approach (inspired by the ALOHAnet wireless system) where multiple computers on a coaxial cable could send packets whenever the line was free and detect collisions if two packets overlapped computerhistory.org. Metcalfe’s 1973 memo and a 1976 paper introduced Ethernet running at 2.94 Mb/s, later standardized to 10 Mb/s en.wikipedia.org en.wikipedia.org. By the 1980s, Ethernet became the dominant LAN solution in businesses, allowing PCs and workstations in the same building to network easily. Competing LAN technologies included IBM’s Token Ring (announced 1984) and others like ARCNET (1977) en.wikipedia.org, but Ethernet’s simplicity and speed won out. Ethernet kept evolving: it went from 10 Mb/s (1980) to 100 Mb/s Fast Ethernet (1995) to Gigabit and now multi-gigabit speeds, maintaining backward compatibility en.wikipedia.org.

On a larger scale, commercial wide area networks emerged. Companies like Telenet and Tymnet in the mid-1970s built packet-switched networks that offered dial-up connections to corporate customers computerhistory.org computerhistory.org. These were often based on the X.25 protocol standard (introduced in 1974) which became the backbone of many public data networks in Europe and Canada en.wikipedia.org. By the late ’70s and ’80s, services like CompuServe, Tymnet, and Datapac (Canada) were providing email and timesharing access commercially over X.25 networks computerhistory.org. IBM developed its own proprietary networking architecture called Systems Network Architecture (SNA) (announced 1974) to link IBM mainframes and terminals computerhistory.org. SNA was widely used in enterprises through the 1980s, carrying a huge volume of traffic in closed networks computerhistory.org. However, as TCP/IP and the Internet gained traction, many of these legacy network systems either adapted (IBM eventually added TCP/IP support) or gradually phased out in favor of the Internet’s open standards.

Another significant trend was the rise of Bulletin Board Systems (BBS) and online services for personal computer users in the 1980s. Hobbyists and “pre-Internet” providers like CompuServe, Prodigy, and AOL created dial-up communities where users could post messages, download files, and send email – albeit confined within each service’s network. By 1990, over 2 million North Americans were using online services or BBSes via phone modems computerhistory.org computerhistory.org. These services foreshadowed many Internet applications (email, forums, e-commerce) but were not yet part of the Internet – that integration would come in the 1990s when such services connected to the global Internet or transformed into web-based businesses.

The Internet Opens to the World: Web and ISP Era (1990s)

In the early 1990s, the Internet transitioned from a research network to a global communication medium accessible to the public. Two key developments powered this transformation: the end of restrictions on commercial Internet use, and the invention of the World Wide Web.

Internet Service Providers (ISPs) emerged once the U.S. National Science Foundation lifted its ban on commercial traffic in 1991computerhistory.org. Previously, NSFNET’s backbone was for research and education only, but in 1991 the policy changed to allow commercial use computerhistory.org. Almost immediately, independent ISPs began offering dial-up Internet access to businesses and consumers. Pioneering ISPs like UUNET, PSINet, and CERFnet started in the late ’80s, and The World (operated by Software Tool & Die) is credited as the first ISP to offer dial-up Internet to the general public in 1989. By the mid-1990s, household names like America Online (AOL), CompuServe, and EarthLink were signing up millions of users for Internet dial-up service. The NSFNET backbone was privatized in 1995, turning over main Internet backbone duties to telecommunications companies computerhistory.org. In short, the Internet evolved from a government-funded academic network to a commercial network of interconnected ISPs spanning the globe. This led to an exponential growth of users and traffic; by 1996 the Internet had around 36 million users, and by 2000 over 360 million computerhistory.org.

Meanwhile, at CERN in Switzerland, an innovation was brewing that would make the Internet vastly more useful to non-technical people. In 1989, British computer scientist Tim Berners-Lee proposed a hypertext system to allow easy sharing of information on the Internet computerhistory.org. By Christmas 1990, he had implemented the first World Wide Web server and browser on a NeXT computer computerhistory.org. Berners-Lee’s system introduced URLs (addresses for resources), HTTP (a protocol to retrieve hypertext pages), and HTML (a simple markup language for web pages). Uniquely, his first browser (named WorldWideWeb) was also an editor, embodying the idea that users could not only read but also contribute content computerhistory.org. The World Wide Web went public in August 1991 when CERN released the code, and it slowly began to spread on the Internet.

A turning point came in 1993 with the release of Mosaic, the first popular web browser with a graphical interface. Mosaic was developed at the NCSA by Marc Andreessen and Eric Bina, and unlike earlier browsers it was easy to install and could display images inline with text computerhistory.org computerhistory.org. Mosaic’s intuitive GUI brought millions of new users onto the Web. Suddenly, the Internet was not just for academics sending email or transferring files – it became a multimedia space of websites that anyone could navigate by clicking hyperlinks. After Mosaic, the Web grew exponentially: from only 26 websites in 1993 to over 10,000 by late 1994. Andreessen soon co-founded Netscape, whose Navigator browser became the dominant way to surf the Web by 1995, until Microsoft entered the fray with Internet Explorer leading to the late-90s “browser wars” computerhistory.org computerhistory.org.

The Web boom fueled the dot-com revolution. By the late 1990s, companies and startups rushed to create websites and online businesses. Early successful sites included Amazon.com (1995) and eBay (1995) for e-commerce, and portals like Yahoo! (1994) for search and navigation. The surge of investment led to a dot-com stock bubble that peaked in 2000 before a rapid downturn in 2000–2001 computerhistory.org computerhistory.org. Nonetheless, the Internet was by then irrevocably part of everyday life, with tens of millions of people around the world emailing, browsing news, shopping online, and chatting on the Internet.

During the 1990s, critical infrastructure was also put in place. The Domain Name System had already distributed naming duties to organizations (with suffixes like .com, .org, .edu). Internet governance evolved to coordinate IP addresses and domain names (ICANN was founded in 1998). Backbone capacities grew as telecom companies laid fibre optic lines, increasing bandwidth and enabling faster access (the jump from dial-up 56kbps modems to broadband DSL/cable in the late 90s and early 2000s greatly improved user experience). By 1999, the stage was set for the next leap: networking without wires.

Wireless Networking Breakthroughs

One of the most significant advances in networking has been the elimination of wires, allowing devices to connect over the air. Early experiments in wireless data networking go back to the 1960s. The ALOHANET system, developed at the University of Hawaii and launched in 1970, was a pioneering packet radio network – effectively a wireless LAN that used radio waves to connect computers on different islands computerhistory.org. ALOHANET introduced techniques for managing a shared radio channel (the “ALOHA protocol”), which later influenced Ethernet’s design for cable networks computerhistory.org. In the 1970s, ARPA also sponsored a packet radio project. By 1977, mobile packet radios (like the one in the demonstration van) were communicating with fixed networks, proving that mobile nodes could join the Internet computerhistory.org computerhistory.org. These projects were ahead of their time: while they showed wireless networking was possible, the technology wasn’t yet cheap or fast enough for mass adoption.

The true wireless revolution in networking came in the 1990s. In 1997, the IEEE finalized the first 802.11 Wi-Fi standard, allowing local wireless connections at about 2 Mb/s. Two years later in 1999, Wi-Fi got a branding push – the Wireless Ethernet Compatibility Alliance coined the term “Wi-Fi” and introduced interoperability certification. That same year, Apple released its AirPort base station and Wi-Fi cards for the iBook laptop, popularizing Wi-Fi for home users computerhistory.org computerhistory.org. Suddenly, one could connect laptops and PCs in a home or office without running Ethernet cables. Wi-Fi hotspots began appearing in coffee shops, airports, and college campuses, providing convenient Internet access. Over subsequent years, Wi-Fi standards improved (802.11b to 11 Mb/s in 1999, g to 54 Mb/s in 2003, and now 802.11ac/ax in the hundreds of Mb/s to gigabit range). Today Wi-Fi is ubiquitous in homes and businesses, an essential part of local networking.

In parallel, cellular networks evolved from purely voice communication to data. The first generation (1G) analog cell networks of the 1980s gave way to 2G digital systems in the 1990s (like GSM, which allowed text messaging). For Internet access, an early milestone was NTT DoCoMo’s i-mode service in Japan, launched February 1999 as the world’s first mobile Internet platform eurotechnology.com. i-mode enabled web browsing, email, and mobile payments on cell phones, and by 2002 it had over 34 million subscribers computerhistory.org. This far surpassed anything available elsewhere at the time – it would take roughly another decade for the rest of the world to catch up to what Japanese users enjoyed in the early 2000s computerhistory.org. In other regions, early “mobile web” efforts used WAP (Wireless Application Protocol) and rudimentary browsers, but these were slow and limited, so adoption was modest computerhistory.org.

True mobile broadband arrived with 3G cellular networks in the early 2000s (e.g. EV-DO, W-CDMA systems), offering a few hundred kb/s to a few Mb/s – enough for basic web and email on phones. The breakthrough device was arguably the Apple iPhone (2007), which, combined with 3G data and a full web browser, demonstrated the potential of the mobile Internet to millions of new users. Following 3G, 4G/LTE networks in the 2010s provided tens of Mb/s, making high-quality video streaming and complex web applications feasible on mobile devices. As of the mid-2020s, the rollout of 5G networks is underway, promising gigabit speeds and ultra-low latency over wireless, which could enable new applications like real-time VR/AR and massive IoT (Internet of Things) connectivity.

Bluetooth (introduced 1998) also deserves mention as a short-range wireless technology, enabling personal area networks for connecting peripherals, though it is not used for general Internet access. Together, Wi-Fi and cellular data freed networked computing from the tether of wires, allowing the Internet to permeate every aspect of daily life – from smartphones and tablets to smart appliances and connected cars.

The Modern Internet: Scale, Impact, and Ongoing Evolution

From a handful of nodes in 1969, the Internet has grown to an immense, planet-spanning network that connects the majority of humankind. As of 2023, roughly 5.4 billion people (67% of the world population) use the Internet itu.int itu.int, a number that continues to climb. Each of these users might have multiple connected devices – personal computers, smartphones, tablets, smart TVs – contributing to an estimated 15 billion networked devices globally. The Internet’s traffic volume has exploded, measured in exabytes (billions of gigabytes) per month, fueled by video streaming, cloud computing, and countless online services.

The Internet’s impact on society is difficult to overstate. It has fundamentally changed how we communicate (e.g. instant messaging, Voice over IP calls, social media), how we work (email, telepresence, remote collaboration), and how we access information (search engines, Wikipedia, online news). Entire industries have been transformed or born anew: from e-commerce and online banking to digital entertainment and telemedicine. The World Wide Web is the primary platform for information sharing, and as of the 2020s there are over 1.5 billion websites (though only around 200 million are active). Data-heavy applications, such as YouTube (launched 2005) and Netflix streaming, were made possible by high-speed broadband and content delivery networks that cache data closer to users for efficiency.

The underlying network technology also continues to advance. Fiber optic cables, which first supplemented Internet backbones in the late 1980s, are now common even in the “last mile” to homes, enabling gigabit-speed home Internet. Core Internet links run on optical wavelengths at tens or hundreds of gigabits per second. Routing technology (from early IMPs and fuzzball routers to modern Cisco/Juniper routers) has scaled to handle millions of routes and terabits of throughput. The addressing system moved from IPv4 (with ~4.3 billion addresses, now exhausted) to IPv6 in the 2000s, which provides a virtually inexhaustible pool of addresses for the future growth of connected devices.

Internet governance and structure have also evolved for stability. Organizations like the Internet Society (ISOC) and ICANN oversee standards and naming. The network has proven surprisingly resilient – designed to reroute around failures, it has withstood outages and even physical disruptions. However, challenges remain: security threats (viruses, worms, cyber attacks) emerged alongside growth, starting with incidents like the Morris Worm in 1988 which demonstrated the vulnerability of networked systems computerhistory.org. This has led to a whole field of cybersecurity and ongoing efforts to harden the Internet’s infrastructure.

Looking forward, the Internet continues to push into new frontiers. The Internet of Things (IoT) is connecting everyday objects and sensors (from smart thermostats to industrial machinery) to networks, generating new data streams and automation possibilities en.wikipedia.org. Wireless connectivity is expanding through satellite constellations (e.g. SpaceX’s Starlink) aiming to bring broadband to remote areas. Experiments with network virtualization and software-defined networking (SDN) are making networks more flexible and programmable. Researchers are even exploring quantum networking for the future. Yet, the fundamental principles established by the pioneers – packet switching, internetworking with TCP/IP, end-to-end design – remain central to how the Internet functions.

In just over half a century, computer networking has progressed from isolated terminals and specialized military systems to a ubiquitous, global “network of networks.” It has enabled the digital age, shrinking the effective distance between people and information to zero. This journey was driven by countless innovations and contributors, a few of whom stand out: Leonard Kleinrock (theory of packet networks), Paul Baran and Donald Davies (packet switching concept), Larry Roberts and Bob Taylor (driving ARPANET), Vint Cerf and Bob Kahn (TCP/IP), Tim Berners-Lee (the Web), Robert Metcalfe (Ethernet), and many others – as well as organizations like ARPA, BBN, NSF, and CERN that provided vision and support. The result is the Internet – arguably the most important technological infrastructure of the modern era.

Timeline of Key Milestones in Networking

1830s–1860s: Telegraph networks span continents, enabling the first electrical long-distance communication. Lays groundwork for network concepts (messages transmitted in packets of Morse code over wires).

1876: Telephone invented – voice network grows globally over next decades. Later used for data via modems in computer networking’s early days.
1940: Stibitz’s remote computing demo – first instance of a computer used at a distance via a teleprinter en.wikipedia.org.
1958: SAGE air-defense network operational – 23 sites connected to coordinate radar data computerhistory.org. Also, first commercial modems (Bell 101) introduced at 110 bit/s en.wikipedia.org.
1961–1964: Packet switching concept formulated (Baran at RAND, Davies at NPL) en.wikipedia.org. Time-sharing computers allow multiple users via terminals, inspiring networking needs.
1965: First computer network experiment: TX-2 computer in Massachusetts connects to Q-32 in California over dial-up telephone (Roberts & MIT Lincoln Lab), modems used at 2.4 kb/s – a precursor to ARPANET techtarget.com.
1969: ARPANET launched – first packet-switched network, connecting UCLA, SRI, UCSB, and Utah en.wikipedia.org. October 29, 1969: first message sent.
1971: Email on ARPANET introduced by Ray Tomlinson; “@” chosen for addresses computerhistory.org. Email quickly becomes ARPANET’s most popular application.
1973: Global networking & TCP/IP begin: ARPANET connects to UK and Norway via satellite. Cerf and Kahn design the TCP/IP protocol suite for internetworking computerhistory.org. Ethernet invented at Xerox PARC by Metcalfe and Boggs – birth of LANs computerhistory.org.
1977: TCP/IP test: A van in PRNET (packet radio) communicates through SATNET and ARPANET, in a successful multi-network transmission computerhistory.org. Demonstrates internetworking concept (“Internet” as network of networks).
1981: BITNET, CSNET established – early academic email/file-sharing networks linking universities, later connected to Internet. IBM PC introduced (1981) – personal computers spread, many initially used offline until modem connectivity grows.
1983: Flag Day – Internet is born: ARPANET switches to TCP/IP on Jan 1, 1983 en.wikipedia.org. ARPANET splits into ARPANET and MILNET. DNS invented to map domain names to IP addresses.
1986: NSFNET created at 56 kb/s, expanding to T1 (1.5 Mb/s) by 1988 – a backbone linking U.S. universities en.wikipedia.org. Becomes primary Internet backbone, enabling broader academic access.
1988: Morris Worm, first major Internet worm, spreads and temporarily cripples thousands of computers computerhistory.org – raises awareness of network security.
1989–1991: World Wide Web invented: Tim Berners-Lee proposes the Web at CERN (1989) and develops the first web server & browser by 1990 computerhistory.org. In 1991 CERN releases Web software publicly computerhistory.org.
1991: Commercial Internet begins – NSF lifts ban on commercial use, allowing ISPs to provide public Internet access computerhistory.org. Gopher (1991) and WAIS are early Internet info systems, soon eclipsed by the Web.
1993: Mosaic browser released – user-friendly GUI web browser that popularizes the Web worldwide computerhistory.org. The number of websites and Internet users explodes.
1994–1995: Web commercialization: Amazon and eBay founded (1995). Netscape’s IPO (1995) signals the dot-com boom. Early search engines (AltaVista 1995, Google 1998) and portals (Yahoo! 1994) index the growing Web.
1995: NSFNET decommissioned; Internet backbone traffic handed to commercial carriers computerhistory.org. Dial-up Internet via phone lines is common for households; AOL CDs flood mailboxes.
1998: Google founded – improves web search, greatly aiding information discovery on the Internet.
1999: Wi-Fi era begins: 802.11b Wi-Fi standardized and marketed; Apple AirPort router brings wireless LAN to homes computerhistory.org. Mobile Internet dawns: NTT DoCoMo launches i-mode in Japan, first mass mobile web service.
2000: Dot-com bubble bursts – many early Internet startups collapse, but the Internet itself keeps growing, now essential to business and finance computerhistory.org
2001–2003: Broadband overtakes dial-up in many countries (cable modems, DSL widely deployed). Online music (Napster, then iTunes) and video (YouTube 2005) demonstrate new media distribution models via the Internet.
2004–2007: Web 2.0 trend – rise of user-generated content and social networks (Facebook founded 2004, YouTube 2005, Twitter 2006). Smartphone revolution: Apple releases the iPhone (2007), merging mobile phone with full Internet capabilities, followed by Android phones. Mobile data usage surges.
2010s: Global Internet – over half the world is online. 4G mobile networks and ubiquitous Wi-Fi make high-speed Internet access mobile and pervasive. Cloud computing, IoT devices, and streaming services flourish on the robust network infrastructure.
2020s: 5G rollout begins, promising multi-gigabit wireless connectivity and enabling new applications (like industrial IoT and autonomous systems). The Internet connects 5+ billion people itu.int and countless devices, driving the digital economy. Ongoing efforts aim to close the digital divide for the remaining offline population and to secure and sustain the Internet for the future.

Sources: The information in this report is drawn from historical analyses and archives including the Computer History Museum timelinecomputerhistory.orgcomputerhistory.orgcomputerhistory.org, Wikipedia documentation of network milestonesen.wikipedia.orgen.wikipedia.orgen.wikipedia.org, and official Internet statisticsitu.int, among others. These sources chronicle the technical breakthroughs and key figures that shaped the networks we use today.