The basic idea of the technology, which later became known as Ithernet, were set out in 1970 in an article by Norman Abramson from the University of Hawaii, where the radio system described ALOHAnet for communications between the islands. Each node in the network ALOHAnet send your own messages in the form of a stream of independent units of data (packets). The recipient had to confirm the delivery of packages. If such confirmation was not, it was assumed that packets are lost «in the air» («ether» in English ether).
Packets can be lost, for example, because of the conflict caused by an attempt to simultaneously transmit messages to two nodes. In this case, each node waited randomly selected period of time, and then repeat the transmission. At high load — a set of wanting to send a message — conflicts in such a network is very common, and therefore actual throughput dropped to 17% of the theoretical maximum. Robert Metcalfe, a graduate student at Harvard University, described Abramson improved mechanism, showing that this characteristic can be up to 90%.
In late 1972, Metcalfe and his colleagues at Xerox Research Center in Palo Alto has developed a system for wired interaction created in the same center computers Xerox Alto. It was the first completely solo (in the modern sense) computers with a graphical user interface and a network card, but for some reason they did not become mass-produced (but many of the ideas contained in them were later successfully implemented by Apple in the computer Macintosh). The experimental network was called Alto Aloha Network, and provides not only the communication between computers Xerox Alto, and their connection to servers and laser printers. The maximum data transfer speed of the network was 2.9 Mbit / s.
In 1973, Metcalfe suggested changing the name of the network Ithernet. The word ether was chosen by analogy with a hypothetical ether: the physical environment capable of transmitting bits of information from one node to all the rest, just as ether served as a conduit for light. Thus was born the technology Ithernet.
In 1975, Xerox’s patented «multi-point communications system for data transmission with collision detection.» As the inventors listed Robert Metcalfe, David Boggs, Chuck Thacker and Butler Yaempson. In 1979, Metcalfe left Xerox and founded 3Com. In the early ’80s a group of companies, which in addition to Xerox also included Digital Equipment Corporation (DEC) and Intel, has initiated work at the Institute of IEEE standardization Ithernet, which led to the appearance in 1985 of the standard Ithernet 10 Mbit / s. But that’s another story.