A Technical History of CYCLADES
The Cyclades Packet Switching
Network has its roots in the ARPANET.
Sometime in 1970 a French delegation while on a trip to the United
States discovered the ARPANET and from this trip quite a few reports
were generated and interest in France developed for a French
instantiation of a heterogeneous computer network located in
universities and research centers.
The end result was the development in 1972 of the Cyclades
network. [Recherche N°328]
The Cyclades network had many of the
markings of a modern computer network and indeed the modern Internet
owes much to the Cyclades network. Cyclades had a layered architecture
composed of three main layers, a Data
Transmission Layer, a Transport
Layer, and an Application
Layer, of which the
Terminal Protocol is an example. More importantly the Cyclades
network had the first true implementation of a datagram utilizing
adaptive routing and an unreliable out of order delivery service.
was the packet switching data transmission layer of the Cyclades
network. The ARPANET would borrow from this technology when it developed
the TCP-IP in 1974. [Recherche N°328]
Furthermore Cyclades demonstrated
"complexity at the network's edge", which means the work takes
place within intelligent end-systems (the hosts) had the intelligence.
The only job of CIGALE was to provide a best effort delivery service,
for example, fragmentation and reassembly of packets is handled by the
So with all of this technology why is
the ARPANET generally recognized as the parent of the modern Internet
and the Cyclades network relegated to a footnote (albeit an important
one) in the history of the Internet? For
that the French can thank the European postal and telecom authorities
adoption of the X.25 standard which used Virtual Circuits instead of
Packet Switching as the Data Transmission Protocol. With the X.25
standard in place these authorities carried on a crusade against packet
switched networks and the datagram which led to a reduction in funding
for the Cyclades network, and its eventual dissolution.
Indeed in 1986, "in a book
largely considered in France a kind of bible of signal processing, one
can see the Internet dispatched in some lines from which the comic side
will not escape the reader from the year 2000: 'the need for having
protocols from beginning to end was solved by architecture TCP-IP [...
]. This architecture is obsolete now…' ". [Recherche N°328]
Against this backdrop during the 1980’s the French development of
packet switching technology and products withered, while at the same
time across the Atlantic in America thanks to local area networks (LANs)
and ARPA contracts, American research continued and American companies
developed a wide array of products derived from the ARPANET and later
A timeline of major events in the history of CYCLADES.
A quick overview of the CYCLADES with links to specifics on the architecture.
Annotated references on CYCLADES. Includes all of the references
sited in this web page.
A listing of digitally archived historical resources, and links to
relevant resources on other sites.