It was 35 years ago today that ARPANET, the military network widely regarded as the progenitor of the internet, was switched on.
The Advanced Research Project Agency Network was a wide area network run by the US department of defense. It was used to test new networking technologies - notably large scale packet switching, a then pioneering method of sending data across a network.
ARPANET's protocol suite was known as the Network Control Program (NCP). This wasn't a communications protocol, as such, but made it possible for users to send and receive messages to and from the Interface Message Processor (IMP) subnetwork.
The initial network had four nodes based at UCLA, the Stanford Research Institute, UCSB, and University of Utah. The first link between the nodes was established 21 November 1969, and by 5 December the same year, all four of the nodes were connected.
There are those who claim that the internet was born with ARPANET, arguing that the Net is defined by the kind of large scale packet switching that ARPANET pioneered. Others say that the Internet was born on the day ARPANET switched to the TCP/IP protocol, on 1 January 1983. They argue that the defining characteristic of the internet is that it shares information between many, dissimilar, networks.
No doubt both camps have valid arguments, but there is little doubt about the importance of the role ARPANET played in the development of what came next. By 1973, there were packet-switching networks springing up in other countries, and work began on a way of interconnecting them. Robert Kahn and Vint Cerf put forward a protocol to do just that. It was developed, over the next ten years, into TCP/IP and the internet proper was born. ®