Around the time organizations were rolling out their early LANs, the Internet was beginning to spread within the research and academic communities. The Internet was not the first wide area network (WAN). Earlier research networks had preceded it, and IBM and Digital Equipment Corporation both marketed widely used WAN technology to large organizations. There had also been several commercial WANs, which resembled time-sharing systems with remote users dialing in using personal computers. The Internet was different in two key ways. First, it used public domain communication software developed by researchers while the IBM and DEC networks were proprietary, requiring one to use their hardware and communication software. Second, the Internet was a network of networks, an internet (small i). An organization could connect its LAN to the Internet regardless of networking hardware and software they used internally.
The Internet also differed from the telephone, cable TV and cellular phone networks. Those networks were designed to provide a specific service – telephony or broadcast video, while the Internet was designed to provide low-cost communication between computers connected at the edge of the network. In the Internet model, the users who connect to the network invent and provide applications and services, not the network operator. The Internet was designed from the start to be an end-to-end, “dumb” network that could connect complex devices (computers) at its edges. 1
This end-to-end architecture was critical to the rapid expansion of the Internet. Any user could invent and implement a new application. For example, when Tim Berners-Lee invented the World Wide Web protocol, he wrote Web client and server programs, and allowed others to copy them. Anyone could use his software to create Web sites and to retrieve information from other’s Web sites. Contrast this to, say, the telephone network where only the telephone company can decide to offer a new service like caller ID. On the Internet, anyone could be an inventor or an entrepreneur – innovation and investment took place at the edge of the network.
Programmers realized they could use the Internet protocols within their organizations as well as on the Internet. They began developing applications for their intranets – accessible only to authorized employees – and for extranets, which only selected stakeholders like suppliers and customers could access.
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