How the internet evolved

The Internet is a global network of interconnected computer networks that use the TCP/IP protocol suite. It grew from a small research project into the worldwide network of today.

Stages of evolution

1. 1960s – ARPANET: The US Department of Defense (ARPA) funded a packet-switching network to link research computers. The first message was sent from UCLA to the Stanford Research Institute (SRI) in 1969. Packet switching (Paul Baran, Donald Davies) made the network robust.
2. 1970s – Internetworking: Many separate networks appeared (ARPANET, packet radio, satellite). Vint Cerf and Robert Kahn designed TCP/IP so that different networks could talk to each other. Email appeared in 1971 (Ray Tomlinson).
3. 1983 – TCP/IP adoption: ARPANET switched to TCP/IP on 1 January 1983. DNS was introduced in 1984 to replace host tables.
4. 1980s – NSFNET: The National Science Foundation built a high-speed backbone linking universities and supercomputer centres. This became the backbone of the academic Internet.
5. 1990s – Commercialisation and the Web: Restrictions on commercial traffic over NSFNET were eased from 1991, commercial ISPs started selling access, and NSFNET was retired in 1995 when commercial networks took over the backbone. Tim Berners-Lee created the World Wide Web (1989-91) and browsers such as Mosaic and Netscape made the Internet easy for ordinary users.
6. 2000s onward – Broadband, mobile and social: Broadband, Wi-Fi, smartphones, social media, cloud computing and the Internet of Things made the Internet part of daily life.

ARPANET (1969) -> TCP/IP (1983) -> NSFNET (1986)
      -> Commercial ISPs + WWW (1990s)
      -> Broadband / Mobile / Cloud / IoT (2000s+)

In Nepal, commercial email service began in 1994 through Mercantile Communications, and full Internet access followed in 1995.