Packet switched network

A Packet Switched Network, or PSN, refers to the packet switched networks that existed before the Internet. The history of such networks can be divided into three eras:early networks before the introduction of X.25 and OSI,the X.25 era when many Postal Telephone and Telegraph (PTT) companies introduced networks with X.25 interfaces, and the Internet era when restrictions on connection to the Internet were removed.

Early Networks

ARPANET and SITA HLN became operational in 1969. Before the introduction of X.25 in 1973 [http://www.networkworld.com/newsletters/frame/2008/0128wan1.html] , about twenty different network technologies were developed. There was a debate about the merits of two drastically different views as to proper division of labour between the hosts and the network. In the datagram system the host must detect loss or duplication of packets. Transmission Control Protocol /Internet Protocol (TCP/IP) is the best known example of a host to datagram protocol. In the virtual call system, the network guarantees sequenced delivery of data to the host. This results in a simpler host interface with less functionality than in the datagram model. X.25 is the best known virtual call protocol.

Inexpensive minicomputers were an important component in the early networks. In some cases custom I/O devices were added to allow inexpensive or exotic attachments to communication lines.

Arpanet

This is the principal survivor from the early era. TCP/IP, which was an important component of ARPANET2, was chosen for use in NSFNET which eventually became the Internet.

BNRNET

BNRNET was a network which Bell Northern Research developed for internal use. It initially had only one host but was designed to support many hosts. BNR later made major contributions to the CCITT X.25 project.

cite conference
first = C. C.
last = Martel
authorlink =
coauthors = J. M. Cunningham and M. S. Grushcow
title = THE BNR NETWORK: A CANADIAN EXPERIENCE WITH PACKET SWITCHING TECHNOLOGY
booktitle = IFIP Congress 1974
pages = 10-14
publisher =
date =
location =
url = http://rogerdmoore.ca/PS/BNR/BNRnet.html
doi =
id =
accessdate =

CTNE

Compañía Telefónica Nacional de España was the national telephone company in Spain. They developed a network called RETD. See below for details.

CYCLADES

CYCLADES was an experimental French network. Louis Pouzin was the principal designer. Some ideas from this network were later incorporated into ARPANET.

DDX-1

This was an experimental network from Nippon PTT. It mixed circuit switching and packet switching. It was succeeded by DDX-2.

EIN nee COST II

European Informatics Network was a project to link several national networks. It became operational in 1976.

EPSS

EPSS (Experimental Packet Switching System) was an experiment of the UK Post Office. Ferranti supplied the hardware and software. The handling of link control messages (acknowledgements and flow control) was differed from that of most another networks and is not fully explained in the published literature.

cite conference
first = Roy D.
last = Bright
authorlink =
coauthors = Smith, Michael A.
title = EXPERIMENTAL PACKET SWITCHING PROJECT OF THE UK POST OFFICE
booktitle = Proceedings of the NATO Advanced Study Institute on Computer Communication Networks
publisher= Noordhoff International Publishing
location= Sussex, United Kingdom
date=1973
pages = 435-44
url = http://rogerdmoore.ca/PS/EPSSB.html
doi =
id =
accessdate =

cite conference
first = D J
last = Pearson
authorlink =
coauthors = Wilkin, D
title = Some Design Aspects of a public packet switching network
booktitle = Proceedings of the 2nd ICCC 74
pages = 199-213
publisher =
date = 1974
location =
url = http://rogerdmoore.ca/PS/EPSSFer/EF.html
doi =
id =
accessdate =

[http://www.euclideanspace.com/coms/history/epss/index.htm this page] has pictures of the EPSS exchanges in London, Manchester and Glasgow.

GEIS

As General Electric Information Services (GEIS),General Electric was a major international provider of information services. The company originally designed a telephone network to serve as its internal (albeit continent-wide) voice telephone network.

In 1965, at the instigation of Warner Sinback, a data network based on this voice-phone network was designed to connect GE's four computer sales and service centers (Schenedtady, Phoenix, Chicago, and Phoenix) to facilitate a computer time-sharing service, apparently the world's first commercial online service. (In addition to selling GE computers, the centers were computer service bureaus, offering batch processing services. They lost money from the beginning, and Sinback, a high-level marketing manager, was given the job of turning the business around. He decided that a time-sharing system, based on Kemney's work at Dartmouth--which used a computer on loan from GE--could be profitable. Warner was right.)

After going international some years later, GEIS created a network data center near Cleveland, Ohio. Very little has been published about the internal details of their network. (Though it has been stated by some that Tymshare copied the GEIS system to create their network, Tymnet.) The design was hierarchal with redundant communication links. Two papers provides some details.

cite conference
first = Peter T.
last = Kirstein
authorlink =
coauthors =
title = A SURVEY OF PRESENT AND PLANNED GENERAL PURPOSE EUROPEAN DATA AND COMPUTER NETWORKS
booktitle = Proceedings of the NATO Advanced Study Institute on Computer Communication Networks
publisher= Noordhoff International Publishing
location= Sussex, United Kingdom
date=1973
url = http://rogerdmoore.ca/PS/Kirs1973/Ki.html#GEISCO
doi =
id =
accessdate =

cite journal
last = Schwartz
first = Mischa
authorlink =
coauthors = Boorstyn, Rober R. and Pickholtz, Raymond L.
title = Terminal-Oriented Computer-Communication Networks
journal = Proceedings of the IEEE
volume = 60
issue = 11
pages = 1408–23
publisher =
date = November 1972
url = http://rogerdmoore.ca/PS/TONET/TON.html#GEISCO
doi =
id =
accessdate =

GMD

IPSANET

IPSANET was a semi-private network constructed by I. P. Sharp Associates to serve their time-sharing customers. It became operational in May 1976.

NPL

Donald Davies of the National Physical Laboratory, UK made many important contributions to the theory of packet switching. NPL built a single node network to connect sundry hosts at NPL.

cite conference
first = R. A.
last = Scantlebury
authorlink =
coauthors = Wilkinson, P.T.
title = The National Physical Laboratory Data Communications Network
booktitle = Proceedings of the 2nd ICCC 74
pages = 223-228
publisher =
date = 1974
location =
url =
doi =
id =
accessdate =

OCTOPUS

Octopus was a local network at Lawrence Livermore National Laboratory. It connected sundry hosts at the lab to interactive terminals and various computer peripherals including a bulk storage system.

Philips Research

Philips Research Laboratories in Redhill, Surrey developed a packet switching network for internal use. It was a datagram network with a single switching node.

cite journal
last = Burnett
first =D.J.
authorlink =
coauthors = Sethi, H.R.
title = Packet Switching at Philips Research Laboratories
journal = Computer Networks
volume = 1
issue =
pages = 341–348
publisher = North-Holland Publishing Company
date =
url =
doi =
id =
accessdate =

RCP

RCP was an experimental network created by the French PTT. It was used to gain experience with packet switching technology before the specification of TRANSPAC was frozen. RCP was a virtual-call network in contrast to CYCLADES which was based on datagrams. RCP emphasised terminal to host and terminal to terminal connection; CYCLADES was concerned with host-to-host communication. TRANSPAC was introduced as an X.25 network. RCP may have influenced the specification of X.25.

cite conference
first = A.
last = Bache
authorlink =
coauthors = Matras, Y.
title =Fundamental Choices in the Development of RCP, the Experimental Packet-Switching Data Transmission Service of the French PTT
booktitle =Proceedings of ICCC 76
pages = 311-16
publisher =
date = 1976
location =
url = http://rogerdmoore.ca/PS/RCPBAC/RB.html
doi =
id =
accessdate =

cite conference
first = A.
last = Bache
authorlink =
coauthors = L. Guillou, H. Layec, B. Long and Y. Matras
title = RCP, the Experimental Packet-Switched Data Transmission Service of the French PTT: History, Connections, Control
booktitle =Proceedings of ICCC 76
pages =
publisher =
date = 1976
location =
url = http://rogerdmoore.ca/PS/RCPHCC/RH.html
doi =
id =
accessdate =

cite conference
first = R.
last = Duprés
authorlink =
coauthors =
title = RCP, THE EXPERIMENTAL PACKET-SWITCHED DATA TRANSMISSION SERVICE OF THE FRENCH PTT
booktitle = Proceedings of ICCC 74
pages = 171-85
publisher =
date = 1974
location =
url = http://rogerdmoore.ca/PS/RCPDEP/RD.html
doi =
id =
accessdate =

RETD

Red Especial de Transmisión de Datos was a network developed in Spain. It became operational in 1972 and thus was the first public network.

cite conference
first = G.
last = Alarcia
authorlink =
coauthors = Herrera, S.
title = "C.T.N.E.'s PACKET SWITCHING NETWORK. ITS APPLICATIONS"
booktitle = Proceedings of 2nd ICCC 74
pages = 163-170
publisher =
date = 1974
location =
url = http://rogerdmoore.ca/PS/CTNEA/CTA.html
doi =
id =
accessdate =

cite conference
first = L.
last = Cuenca
authorlink =
coauthors =
title = A PUBLIC PACKET SWITCHING DATA COMMUNICATIONS NETWORK:EIGHT YEARS OF OPERATING EXPERIENCE
booktitle = Conference Record of ICC 80
pages = 39.3.1-39.3.5
publisher = IEEE
date = 1980
location =
url = http://rogerdmoore.ca/PS/CTNEC1.html
doi =
id =
accessdate =

cite conference
first = Luis
last = Lavandera
authorlink =
coauthors =
title =ARCHITECTURE, PROTOCOLS AND PERFORMANCE OF RETD
booktitle = Conference Record of ICC 80
pages = 28.4.1-28.4.5
publisher = IEEE
date = 1980
location =
url = http://rogerdmoore.ca/PS/RETDB.html
doi =
id =
accessdate =

CANNET

"The first experimental packet-switched Nordic telecommunication network SCANNET was implemented in Nordic technical libraries in 70's, and it included first Nordic electronic journal Extemplo. Libraries were also among first ones in universities to accommodate microcomputers for public use in early 80's."

The preceding paragraph taken from: [href="http://edoc.hu-berlin.de/conferences/eunis2001/e/Haarala/HTML/haarala-ch2.html"]

ITA HLN

SITA is a consortium of airlines. Their High Level Network became operational in 1969 at about the same time as ARPANET. It carried interactive traffic and message-switching traffic. As with many non-academic networks very little has been published about it.

cite conference
first = G.J.
last = Chretien
authorlink =
coauthors = Konig, W.M. and Rech, J.H.
title = The SITA Network
url= http://rogerdmoore.ca/PS/SITAB.html
booktitle = Proceedings of the NATO Advanced Study Institute on Computer Communication Networks
publisher= Noordhoff International Publishing
location= Sussex, United Kingdom
pages = 373-396
year = 1973

NA

Systems Network Architecture (SNA) is IBM's proprietary networking architecture created in 1974. An IBM customer could acquire hardware and software from IBM and lease private lines from a common carrier. This allowed construction of a private network.

cite conference
first = R.J.
last = Sundstrom
authorlink =
coauthors = G.D. Schultz
title = "1980 SNA'S First Six Years: 1974-1980"
booktitle =Proceedings of 5th ICCC 80
pages = 578-585
publisher =
date = 1980
location =
url =http://rogerdmoore.ca/PS/SNA6Y/SNA6.html
doi =
id =
accessdate =

Telenet

Telenet was the first FCC-licensed public data network in the United States. It was founded by former ARPA IPTO director Larry Roberts as a means of making ARPANET technology public. He had tried to interest AT&T in buying the technology, but the monopoly's reaction was that this was incompatible with their future. Bolt, Beranack and Newman (BBN) provided the financing.

It initially used ARPANET technology but changed the host interface to X.25 and the terminal interface to X.29. Telenet designed these protocols and helped standardize them in the CCITT. Telenet was incorporated in 1973 and started operations in 1975. It went public in 1979 and was then sold to GTE.

Tymnet

Tymnet was an international data communications network headquartered in San Jose, CA that utilized virtual call packet switched technology and used X.25, SNA/SDLC, BSC and ASCII interfaces to connect host computers (servers)at thousands of large companies, educational institutions, and government agencies. Users typically connected via dial-up connections or dedicated async connections. The business consisted of a large public network that supported dial-up users and a private network business that allowed government agencies and large companies (mostly banks and airlines) to build their own dedicated networks. The private networks were often connected via gateways to the public network to reach locations not on the private network. Tymnet was also connected to dozens of other public networks in the U.S. and internationally via X.25/X.75 gateways. (Interesting note: Tymnet was not named after Mr. Tyme. Another employee suggested the name.)

cite conference
last = TYMES
first = LA ROY W.
authorlink =
coauthors =
title = TYMNET — A terminal oriented communication network
booktitle = Proceedings of the SJCC 1971
volume=38
pages = 211-16
publisher =
date =
location =
url = http://rogerdmoore.ca/PS/TYMNET/TY.html
doi =
id =
accessdate =

cite journal
last = TYMES
first = LA ROY W.
authorlink =
coauthors =
title = Routing and Flow Control in TYMNET
journal =IEEE TRANSACTIONS ON COMMUNICATIONS
volume = COM-29
issue = 4
pages =392–98
publisher =
date = APRIL 1981
url =http://www.rogerdmoore.ca/PS/TYMFlow/TF.html
doi =
id =
accessdate =

X.25 Era

There were two kinds of X.25 networks. Some such as DATAPAC and TRANSPAC were initially implemented with an X.25 external interface. Some older networks such as TELENET and TYMNET were modified to provide a X.25 host interface in addition to older host connection schemes. DATAPAC was developed by Bell Northern Research which was a joint venture of Bell Canada (a common carrier) and Northern Telecom (a telecommunications equipment supplier). Northern Telecom sold several DATAPAC clones to foreign PTTs including the Deutsche Bundespost. X.75 and X.121 allowed the interconnection of national X.25 networks. A user or host could call a host on a foreign network by including the DNIC of the remote network as part of the destination address.

Austpac

AUSTPAC is an Australian public X.25 network operated by Telstra. Started by the then-Telecom in the early 1980s, AUSTPAC was Australia's first public packet-switched data network, supporting applications such as on-line betting, financial applications — the Australian Tax Office has made use of AUSTPAC — and remote terminal access to academic institutions, who maintained their connections to AUSTPAC up until the mid-late 1990s in some cases. Access can be via a dial-up terminal to a PAD, or, by linking a permanent X.25 node to the network.

Autonet

ConnNet

ConnNet was a packet switched data network operated by the Southern New England Telephone Company serving the state of Connecticut.

Datanet 1

Datanet 1 was the public switched data network operated by the Dutch PTT Telecom (now known as KPN). Strictly speaking Datanet 1 only referred to the network and the connected users via leased lines (using the X.121 DNIC 2041), the name also referred to the public PAD service "Telepad" (using the DNIC 2049). And because the main Videotex service used the network and modified PAD devices as infrastructure the name Datanet 1 was used for these services as well. Although this use of the name was incorrect all these services were managed by the same people within one department of KPN contributed to the confusion.

Datapac

DATAPAC was the first operational X.25 network (1976). It covered major Canadian cities and was eventually extended to smaller centres.

Datex-P

Deutsche Bundespost operated this national network in Germany. The technology was acquired from Northern Telecom.

Eirpac

Eirpac is the Irish public switched data network supporting X.25 and X.28. It was launched in 1984, replacing Euronet. Eirpac is run by Eircom.

Iberpac

Iberpac is the Spanish public packet switched network, providing X.25 services. Iberpac is run by Telefonica.

Isranet

JANET

JANET was the UK academic and research network, linking all universities, higher education establishments, publicly funded research laboratories. The X.25 network was based mainly on GEC 4000 series switches, and run X.25 links at up to 8 Mbit/s in its final phase before being converted to an IP based network. The JANET network grew out of the 1970s SRCnet (later called SERCnet) network.

Luxpac

MDNS

PSS

PSS was the UK Post Office (later to become British Telecom) national X.25 network with a DNIC of 2342. British Telecom renamed PSS under its GNS (Global Network Service) name, but the PSS name has remained better known. PSS also included public dial-up PAD access, and various InterStream gateways to other services such as Telex.

RCA

aponet

Telepac

Transpac

Transpac was the national X.25 network in France. It was developed locally at about the same time as DataPac in Canada. The development was done by the French PTT and influenced by the experimental RCP network. It began operation in 1978.

Venus-P

Internet Era

When Internet connectivity was made available to anyone who could pay for an ISP subscription, the distinctions between national networks blurred. The user no longer saw network identifiers such as the DNIC. Some older technologies such as circuit switching have resurfaced with new names such as fast packet switching. Researchers have created some experimental networks to complement the existing Internet.

Internet2

Internet2 is not an actual network. It is a research consortium which has created the Abilene Network.

National LambdaRail

National LambdaRail is a high-speed national computer network in the United States that runs over fiber-optic lines, and is the first transcontinental Ethernet network working to establish a direct line of communications between international parties.

TransPAC2

ee also

*Public switched data network
*Public Data Network
*Compuserve
*Virtual private network

External links

* [http://textfiles.group.lt/hacking/icebook2.txt "The Guide to Hacking & Phreaking, Issue #2", Liquid Jesus]
* [http://www.zakon.org/robert/internet/timeline/ "Hobbes' Internet Timeline v8.1", Robert H'obbes' Zakon, Zakon Group LLC]
* [http://www.rogerdmoore.ca/PS 20+ articles on packet switching in the 70s]
* [http://www.phrack.org/issues.html?issue=18&id=3#article "An Introduction to Packet Switched Networks", "Phrack", 05/3/88]