The rules of information exchange
IDEA No 15
INTERNET PROTOCOL SUITE
In the early ’70s, following the launch of ARPANET, several more packet-switching networks emerged. Robert Kahn had the idea of joining them up. To do this, they would need a common set of rules.
Researchers from the Stanford Research Institute monitor the first Internet transmission, taking place in the garden of the Alpine Inn.
One of these networks was a packet radio system that operated out of a converted bread van provided by Stanford Research Institute (SRI). A regular stop was the Alpine Inn. Known locally as Zott’s, it was described in 1909 by the president of SRI as ‘unusually vile, even for a roadhouse, a great injury to the University and a disgrace to San Mateo County’. This view was not shared by Stanford students.
It was outside Zott’s, on 22 November 1977, that the van sent a message to London via Norway and back to California by satellite. It travelled 90,000 miles in two seconds. At that moment, outside a biker bar in Silicon Valley, the internet was born.
This first successful test used Transmission Control Protocol (TCP), but as the Net grew, more protocols were required. User Datagram Protocol (UDP) was created for files where speed was more important than sequence, such as voice and game play. Internet Protocol (IP) was developed at a higher level to label and transport packets. This suite of protocols became known as TCP/IP. Its evolution over the next 20 years was managed by one of the driving forces of the internet, Jon Postel.
In 1982, the decision was made to convert all networks on ARPANET to TCP/IP by the end of the year. On 1 January 1983 the switch was made permanent and barely celebrated. With hindsight we realize what a momentous occasion this was. (see The Internet) It heralded the start of the Information Age.
By the late ’80s, most public networks had joined the internet, but commercial traffic was banned from the government-sponsored platform. In 1988, Vinton Cerf asked to connect one commercial system, MCI Mail, as a test. As he anticipated, when the other email providers found out, they clambered to join too. They all ran on TCP/IP. Once they were on the internet, all these previously isolated networks could talk to one another. Kahn’s vision had been realized.
Kahn and Cerf get the glory but, like most things, the success of TCP/IP is down to many people. Chief among them perhaps is Postel. The behaviour he encouraged, known as Postel’s Law, seems wise beyond the implementation of TCP/IP: ‘Be conservative in what you do, be liberal in what you accept from others.’■
‘Be conservative in what you do, be liberal in what you accept from others.’
The inside of the converted bread van from which the first message was sent over the internet.