CYCLADES

The CYCLADES computer network (French pronunciation: ​[siklad]) was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching, and was developed to explore alternatives to the ARPANET design. The network supported general local network research.[1]

The CYCLADES network was the first to make the hosts responsible for the reliable delivery of data, rather than this being a centralized service of the network itself. Datagrams were exchanged on the network using transport protocols that do not guarantee reliable delivery, but only attempt best-effort. To empower the network leaves, the hosts, to perform error-correction, the network ensured end-to-end protocol transparency, a concept later to be known as the end-to-end principle. This simplified network design, reduced network latency, and reduced the opportunities for single point failures. The experience with these concepts led to the design of key features of the Internet protocol in the ARPANET project.[2][3][4]

The network was sponsored by the French government, through the Institut de Recherche en lnformatique et en Automatique (IRIA), the national research laboratory for computer science in France, now known as INRIA, which served as the co-ordinating agency. Several French computer manufacturers, research institutes and universities contributed to the effort. CYCLADES was designed and directed by Louis Pouzin.[5][6]

Conception and deployment

Design and staffing started in 1972, and November 1973 saw the first demonstration, using three hosts and one packet switch. Deployment continued in 1974, with three packet switches installed by February, although at that point the network was only operational for three hours each day. By June the network was up to seven switches, and was available throughout the day for experimental use.

A terminal concentrator was also developed that year, since time-sharing was still a prevalent mode of computer use. In 1975, the network shrank slightly due to budgetary constraints, but the setback was only temporary. At that point, the network provided remote login, remote batch and file transfer user application services.

By 1976 the network was in full deployment, eventually numbering 20 nodes with connections to NPL in London, ESA in Rome, and to the European Informatics Network (EIN).

Technical details

CYCLADES used a layered architecture, as did the Internet. The basic packet transmission like function, named CIGALE, was novel; it provided an unreliable datagram service (the word was coined by Louis Pouzin by combining data and telegram). Since the packet switches no longer had to ensure correct delivery of data, this greatly simplified their design.[7]

“The inspiration for datagrams had two sources. One was Donald Davies' studies. He had done some simulation of datagram networks, although he had not built any, and it looked technically viable. The second inspiration was I like things simple. I didn't see any real technical motivation to overlay two levels of end-to-end protocols. I thought one was enough.”

— Louis Pouzin[3]

The CIGALE network featured a distance vector routing protocol, and allowed experimentation with various metrics. it also included a time synchronization protocol in all the packet switches. CIGALE included early attempts at performing congestion control by dropping excess packets.

The name CIGALE—(French pronunciation: ​[siɡal]) which is French for cicada—originates from the fact that the developers installed a speaker at each computer, so that "it went 'chirp chirp chirp' like cicadas" when a packet passed a computer.[8]

An end-to-end protocol built on top of that provided a reliable transport service, on top of which applications were built. It provided a reliable sequence of user-visible data units called letters, rather than the reliable byte stream of TCP. The transport protocol was able to deal with out-of-order and unreliable delivery of datagrams, using the now-standard mechanisms of end-end acknowledgments and timeouts; it also featured sliding windows and end-to-end flow control.

Demise

By 1976, the French PTT was developing Transpac, a packet network based on the emerging X.25 standard. The academic debates between datagram and virtual circuit networks continued for some time, but were eventually cut short by bureaucratic decisions.

Data transmission was a state monopoly in France at the time, and IRIA needed a special dispensation to run the CYCLADES network. The PTT did not agree to funding by the government of a competitor to their Transpac network, and insisted that the permission and funding be rescinded. By 1981, Cyclades was forced to shut down.

Legacy

The most important legacy of CYCLADES was in showing that moving the responsibility for reliability into the hosts was workable, and produced a well-functioning service network. It also showed that it greatly reduced the complexity of the packet switches. The concept became a cornerstone in the design of the Internet.[2][3][4]

The network was also a fertile ground for experimentation, and allowed a generation of French computer scientists to experiment with networking concepts.[1] Louis Pouzin and the CYCLADES alumni initiated a number of follow-on projects at IRIA to experiment with local area networks, satellite networks, the Unix operating system, and the message passing operating system Chorus.

Hubert Zimmermann used his experience in CYCLADES to influence the design of the OSI model, which is still a common pedagogical tool.

CYCLADES alumni and researchers at IRIA/INRIA were also influential in spreading adoption of the Internet in France, eventually witnessing the success of the datagram-based Internet, and the demise of the X.25 and ATM virtual circuit networks.

See also

References

  • Pouzin, Louis (1973). "Presentation and Major Design Aspects of the Cyclades Computer Network". Proceedings of the NATO Advanced Study Institute on Computer Communication Networks. Sussex, United Kingdom: Noordhoff International Publishing. pp. 415–434.
  • Pouzin, Louis (1974). "CIGALE, the packet switching machine of the CYCLADES computer network". Proc of IFIP. Stockholm, Sweden. pp. 155–159.
  • Pouzin, Louis (1975). "The CYCLADES network-present state and development trends". Symposium on Computer Networks. Gaithersburg, Maryland: IEEE Computer Society. pp. 8–13.

Notes

  1. ^ a b Kim, Byung-Keun (2005). Internationalising the Internet the Co-evolution of Influence and Technology. Edward Elgar. pp. 51–55. ISBN 1845426754.
  2. ^ a b Bennett, Richard (September 2009). "Designed for Change: End-to-End Arguments, Internet Innovation, and the Net Neutrality Debate" (PDF). Information Technology and Innovation Foundation. p. 11. Retrieved 11 September 2017.
  3. ^ a b c Pelkey, James. "6.3 CYCLADES Network and Louis Pouzin 1971-1972". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968-1988.
  4. ^ a b Pelkey, James. "6.4 Transmission Control Protocol (TCP) 1973-1976". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968-1988.
  5. ^ "The internet's fifth man". Economist. 13 December 2013. Retrieved 11 September 2017.
  6. ^ "Say Bonjour to the Internet's Long-Lost French Uncle". Wired. 3 January 2013. Retrieved 11 September 2017.
  7. ^ "A Technical History of CYCLADES" Archived 2013-09-01 at the Wayback Machine, Technical Histories of the Internet & other Network Protocols (THINK), University of Texas, 11 June 2002
  8. ^ Gillies, James and Robert Cailliau (2000). How the Web Was Born: The Story of the World Wide Web. Oxford University Press. p. 38. ISBN 978-0-19-286207-5.

Further reading

  • Louis Pouzin (editor), The Cyclades Computer Network: Toward Layered Network Architectures (North-Holland, Amsterdam, 1982)

External links

Aegean Sea (theme)

The Theme of the Aegean Sea (Greek: θέμα τοῦ Αἰγαίου Πελάγους, thema tou Aigaiou Pelagous) was a Byzantine province in the northern Aegean Sea, established in the mid-9th century. As one of the Byzantine Empire's three dedicated naval themes (Greek: θέματα ναυτικᾶ), it served chiefly to provide ships and troops for the Byzantine navy, but also served as a civil administrative circumscription.

Antimilos

Antimilos (Greek: Αντίμηλος) is a Greek island in the Cyclades, 13 miles (21 kilometres) northwest of Milos. Administratively, it is part of the municipality of Milos. Antimilos is an uninhabited mass of trachyte (671 m height), often called Erimomilos (Desert Milos). It is a volcanic island and the crater is still obvious. Ancient inhabitants transformed the crater to an open rain tank. On the island lives a rare variation of the common goat called Capra aegagrus pictus. It is similar but not the same as the Cretan goat known as "kri-kri" (Capra aegagrus creticus).

Cycladic culture

Cycladic culture (also known as Cycladic civilisation or, chronologically, as Cycladic chronology) was a Bronze Age culture (c. 3200–c. 1050 BC) found throughout the islands of the Cyclades in the Aegean Sea. In chronological terms, it is a relative dating system for artefacts which broadly complements Helladic chronology (mainland Greece) and Minoan chronology (Crete) during the same period of time.

Donousa

Donousa (Greek: Δονούσα, also Δενούσα Denousa) is an island and a former community in the Cyclades, Greece. Since the 2011 local government reform it is part of the municipality Naxos and Lesser Cyclades, of which it is a municipal unit. Donousa is the easternmost island of the Lesser Cyclades.

HSC Cyclades Express

Cyclades Express is a high speed catamaran operated by NEL Lines in the Aegean.

Irakleia (Cyclades)

Irakleia or Heraklia (Greek: Ηρακλειά; Ancient Greek: Ἡράκλεια) is an island and a former community in the Cyclades, Greece. Since the 2011 local government reform it is part of the municipality Naxos and Lesser Cyclades, of which it is a municipal unit. Its population was officially 141 inhabitants at the 2011 census, and its land area 17.795 square kilometres (6.9 sq mi). It is a small island between the islands of Naxos and Ios. Close to Schoinoussa, Koufonisi, Donoussa, and Keros, together they form the Lesser Cyclades. The port is called Agios Georgios, while the "capital"/chora on the top of the island is called Panagia (Madonna). The biggest caves in the Cyclades are located on Irakleia. Irakleia can be reached by ferries from Athens, Naxos and Paros.

Kardiotissa

Kardiotissa (Greek: Καρδιώτισσα), anciently, Lagusa or Lagousa (Ancient Greek: Λάγουσα or Lagussa or Lagoussa (Λαγοῦσσα), is a Greek island in the Cyclades. It is uninhabited and administratively a part of the island community of Sikinos. It lies midway between that island and the island of Folegandros.

Kea (island)

Kea (Greek: Κέα), also known as Tzia (Greek: Τζια) and in antiquity Keos (Greek: Κέως, Latin: Ceos), is a Greek island in the Cyclades archipelago in the Aegean Sea. Kea is part of the Kea-Kythnos regional unit.

The Cyclades Islands are usually defined by laid-back Naxos and Paros, the more bohemian Mykonos and Ios and the picture perfect Santorini. Yet not many have heard of Kea – the closest Cyclades getaway to the mainland, but one that feels much, much further away.

Kimolos

Kimolos (Greek: Κίμωλος; Latin: Cimolus) is a Greek island in the Aegean Sea. It lies on the southwest of the island group of Cyclades, near the bigger island of Milos. Kimolos is the administrative center of the municipality of Kimolos, which also includes the uninhabited islands of Polyaigos, Agios Efstathios and Agios Georgios. The island has a land area of 36 square kilometres (13.900 sq mi), while the municipality's land area is 53.251 square kilometres (20.560 sq mi), and it reported a population of 910 inhabitants in the 2011 census.

List of caves in Greece

This article show a list of caves in Greece.

List of islands of Greece

Greece has a large number of islands, with estimates ranging from somewhere around 1,200 to 6,000, depending on the minimum size to take into account. The number of inhabited islands is variously cited as between 166 and 227.The largest Greek island by area is Crete, located at the southern edge of the Aegean Sea. The second largest island is Euboea, which is separated from the mainland by the 60m-wide Euripus Strait, and is administered as part of the Central Greece region. After the third and fourth largest Greek Islands, Lesbos and Rhodes, the rest of the islands are two-thirds of the area of Rhodes, or smaller.

The Greek islands are traditionally grouped into the following clusters: the Argo-Saronic Islands in the Saronic gulf near Athens; the Cyclades, a large but dense collection occupying the central part of the Aegean Sea; the North Aegean islands, a loose grouping off the west coast of Turkey; the Dodecanese, another loose collection in the southeast between Crete and Turkey; the Sporades, a small tight group off the coast of Euboea; and the Ionian Islands, chiefly located to the west of the mainland in the Ionian Sea. Crete with its surrounding islets and Euboea are traditionally excluded from this grouping.

Nisiotika

Nisiotika (Greek: νησιώτικα) is the name of the songs and dances of Greek islands including a variety of Greek styles, played by ethnic Greeks in Greece, Cyprus, Australia, the United States and elsewhere.

The Aegean Islands have a well known folk dance tradition, which comes from the dances of ancient Greece like: syrtos, sousta and ballos. The lyre is the dominant folk instrument and other like laouto, violin, askomandoura with Greek characteristics vary widely. In the Aegean, the violin and the Cretan lyra are very widespread Greek musical instruments.

Famous representative musicians and performers of Nisiotika include: Mariza Koch as credited with reviving the field in the 1970s, Yiannis Parios, Domna Samiou, the Konitopouloi family (including Giorgos Konitopoulos, Vangelis Konitopoulos, Eirini Konitopoulou, Nasia and Stella Konitopoulou) and others.

There are also prominent elements of Cretan music on the Dodecanese Islands and Cyclades.

Greek folk dances of Nisiotika include:

Ballos

Ikariotikos

Kamara (dance)

Kalymnikos

Karavas (dance) of Naxos

Lerikos

Mihanikos

Parianos

Pirgousikos of Chios

Pidikhtos

Rhoditikos

Sousta Lerou

Sousta Tilou

Syrtos Kythnou

Syrtos Serifou

Syrtos Naxou

Trata

Panthiraikos F.C.

Panthiraikos Football Club (Greek: Πανθηραϊκος Α.Ο.) is a Greek football club based in Santorini, Cyclades. They currently play in Gamma Ethniki, the third division of Greek soccer.

Regional units of Greece

The 74 regional units (Greek: περιφερειακές ενότητες, perifereiakés enóti̱tes, sing. περιφερειακή ενότητα, perifereiakí̱ enóti̱ta) are administrative units of Greece. They are subdivisions of the country's 13 regions, further subdivided into municipalities. They were introduced as part of the "Kallikratis" administrative reform on 1 January 2011 and are comparable in area and, in the mainland, coterminous with the pre-"Kallikratis" prefectures of Greece.

Rineia

Rineia or Rhenea (Ρήνεια), anciently Rheneia (Ancient Greek: Ῥήνεια) or Rhenaia (Ῥηναῖα), or Rhene (Ῥήνη), is a Greek island in the Cyclades. It lies just west of the island of Delos and further southwest of the island of Mykonos, of which it and Delos are administratively a part. Its area is 14 km2 (5 sq mi). It had a small population until the 1980s, but is currently uninhabited. In ancient times the island was subdued by the tyrant Polycrates of Samos and dedicated to the Delian Apollo; and the southern half of the island was the necropolis of Delos. In the sixth year of the Peloponnesian War (426 BCE), the Athenians purified Delos. They removed all the tombs from that island, and declared it to be unlawful henceforth for any living being to be born or die within it, and that every pregnant woman should be carried over to the island of Rheneia in order to be delivered.

Schoinoussa

Schoinoussa or Schinoussa (Greek: Σχοινούσσα, before 1940: Σχοινούσα, pronounced [sçiˈnusa]; anciently, Ancient Greek: Σχινοῦσσα) is an island and a former community in the Cyclades, Greece. Since the 2011 local government reform it is part of the municipality Naxos and Lesser Cyclades, of which it is a municipal unit. It lies south of the island of Naxos, in the Lesser Cyclades group, between the island communities of Irakleia and Koufonisia. The population was 256 inhabitants at the 2011 census. Its land area is 8.512 square kilometres (3.29 sq mi).

Serifopoula

Serifopoula is a Greek island in the Cyclades. It is a part of the municipality of Serifos. Serifopoula was uninhabited at the 2001 Greek census.

Tinos

Tinos (Greek: Τήνος [ˈtinos]) is a Greek island situated in the Aegean Sea. It is located in the Cyclades archipelago. In antiquity, Tinos was also known as Ophiussa (from ophis, Greek for snake) and Hydroessa (from hydor, Greek for water). The closest islands are Andros, Delos, and Mykonos. It has a land area of 194.464 square kilometres (75.083 sq mi) and a 2011 census population of 8,636 inhabitants.

Tinos is famous amongst Greeks for the Church of Panagia Evangelistria, its 80 or so windmills, about 1000 artistic dovecotes, 50 active villages and its Venetian fortifications at the mountain, Exomvourgo. On Tinos, both Greek Orthodox and Roman Catholic populations co-exist, and the island is also well known for its famous sculptors and painters, such as Nikolaos Gysis, Yannoulis Chalepas and Nikiforos Lytras.

The island is located near the geographical center of the Cyclades island complex, and because of the Panagia Evangelistria church, with its reputedly miraculous icon of Virgin Mary that it holds, Tinos is also the center of a yearly pilgrimage that takes place on the date of the Dormition of the Virgin Mary (15 August, "Dekapentavgoustos" in Greek). This is perhaps the most notable and still active yearly pilgrimage in the region of the eastern Mediterranean. Many pilgrims make their way the 800 metres (2,600 feet) from the ferry wharf to the church on their hands and knees as sign of devotion.

History
Pioneers
Transmission
media
Network topology
and switching
Multiplexing
Networks

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