CYCLADES

CYCLADES was a French pilot project under the direction of Louis Pouzin, which aimed to create a global telecommunications network based on the exchange of data packets. The project was founded in 1971 and 1978 because of changes in priorities for France's national budget, especially because it was recognized the danger to the state telecom monopoly in favor of Transpac (X.25 ), the backbone of Minitel, abandoned. Some developments of the project CYCLADES represent key technologies that have enabled today's Internet only.

Formation

In 1970 the project ARPANET, a predecessor of the Internet in France was known due to the visit of a French delegation at BBN Technologies in the United States. This became interested in the concept of a decentralized network. At the same time, France had only dedicated data networks, the individual organizations were reserved. As a result, the project was CYCLADES.

Special

CIGALE and the datagram

In CYCLADES it was decided as it did in previous technical approaches (eg, the ARPANET ) to divide the data into packets for transmission and then reassemble at the destination. The ARPANET was used at that time Virtual connections ( Virtual Circuit VC). In contrast, CYCLADES first came the so-called datagram (French " datagrams ," analogous to " télégramme " - ie a " data message " ) is used - a connectionless technology.

Virtual connections are logical channels that arise if one splits bitstreams into packets to several of these bit streams - almost simultaneously - to send over a common physical communication link can. Thus, the receiver can assign each packet the bit streams properly, they will be provided with a connection identifier. It takes nothing other than that multiple physical communication links can be simulated in order to save lines.

CIGALE (French for Cicada ), responsible for packet switching layer of CYCLADES, now went a step further. Instead of building virtual connections, data packets with the particular source and destination address are provided. Each individual package of a bit stream can freely and independently of the other packages his way through the network now. This method was the model for the protocol suite TCP / IP, which was developed from 1973 onwards for the ARPANET and on 1 January 1983, the network used until then Control Program ( NCP ) replaced - from the perspective of the art of the beginning of today's Internet.

Importance for today's Internet

The scientists who were involved in the development of CYCLADES and ARPANET, cultivated a knowledge exchange and was partially even with both of these projects. This led to a significant technology transfer in both directions.