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Page history last edited by lisa 13 years, 11 months ago




Everyone, We need to start and work on the group part. I googled  ARPAnet and got this list of things we could include...




Background - Sian

Creation - marty

Inital ARPA deployment - sam

Software and protocol development - andrea

Growth - Deborah

Developments - lisa



Other things anyone else thinks necessary please add to this list... many thanks





ARPAnet Background 


ARPAnet was the first wide area packet switching network.  Below explains how ARPAnet began. 


The ARPAnet (Advanced Research Project Agency Network) was developed by ARPA of the US Department of Defense.  It preceded the global Internet.  The management style of ARPA was crucial to the future success of ARPAnet and the Internet as we know it today. 


The initial computer network idea was to enable users of different computers to communicate with each other via a network.  This was designed by JCR Licklider, Bernack and Newman in August 1962.  Today’s internet is based on these ideas.  From these ideas a number of people found out about what now is known as packet switching.  ARPAnet as a company then drew on the different sources. 


The ARPAnet completion report finishes by saying



“..it is somewhat fitting to end on the note that ARPAnet program has had a

strong and direct feedback into the support and strength of computer

science, from which the network itself sprung.”


 In 1968 ARPA’s program plan for ARPAnet was titled “Resource Sharing Computer Networks”.  In the beginning of ARPAnet, and in the development stages, the developers could only see so far ahead.  ARPAnet’s first sites were used to provide unique resources or to provide network support.


Milestones. Some of the milestones in the early history of the ARPANET are summarized below

                                        (taken from http://www.livinginternet.com/i/ii_arpanet.htm)

  • East Coast. In March, 1970, the consulting company Bolt, Beranek & Newman joined the ARPANET, becoming the first ARPANET node on the US east coast.

  • Remote Access. In September, 1971, the first Terminal Interface Processor (TIP) was deployed, enabling individual computer terminals to dial directly into the ARPANET, thereby greatly increasing the ease of network connections and leading to significant growth.

  • 1972. By the end of 1972 there were 24 sites on the ARPANET, including the Department of Defense, the National Science Foundation, NASA, and the Federal Reserve Board.

  • 1973. By the end of 1973 there were 37 sites on the ARPANET, including a satellite link from California to Hawaii. Also in 1973, the University College of London in England and the Royal Radar Establishment in Norway become the first international connections to the ARPANET.

  • 1974. In June, 1974, there were 62 computers connected to the ARPANET.

  • 1977. In March, 1977, there were 111 computers on the ARPANET.

  • 1983. In 1983, an unclassified military only network called MILNET split off from the ARPANET, remaining connected only at a small number of gateways for exchange of electronic mail that could be easily disconnected for security reasons if required. MILNET later become part of the DoD Defense Data Network, or DDN.

  • 1985. By the middle of the 80's there were ARPANET gateways to external networks across North America, Europe, and in Australia, and the Internet was global in scope. Marty Lyons has created a map of the existing network gateways from 18 June 1985.

  • 1990. The ARPANET was retired in 1990. Most university computers that were connected to it were moved to networks connected to the NSFNET,

  • passing the torch from the old network to the new.



Creation of Arpanet

Arpanet is long thought of as the grandfather of the modern day internet.  Initially Arpanet was created to protect the flow of information between different areas of the American military.  This would be accomplished creating a network of geographically separated computers which could exchange information via newly created protocols. 

            These were known as Network Control Protocols (NCP).  The origin of Arpanet however is contrary to belief.  Many people feel the initial development of Arpanet was not for the reason stated above. 

The former director of Arpa, Charles M. Herzfeld claims that Arpanet was not created as a result of a military need, stating "it came out of our frustration that there were only a limited number of large, powerful research computers in the country and that many research investigators who should have access were geographically separated from them."   

Four computers were the first connected in the original Arpanet. They were located in the respective computer research labs of UCLA, Stanford Research Institute, UC Santa Barbara, and the University of Utah.

As the network expanded, different models of computers were connected, creating compatibility problems. The solution rested in a better set of protocols called (Transmission Control Protocol/Internet Protocol) TCP/IP designed in 1982. 

Under Arpanet several major innovations occurred:

·         Email, electronic mail  in 1971,

·         Telnet, a remote connection service for controlling a computer (1972),

·          File transfer protocol (FTP), which allows information to be sent from one computer to another in bulk (1973).

As non-military uses for the network increased, more and more people had access, and it was no longer safe for military purposes. As a result, a military only network, MILnet, was started in 1982. 

Internet Protocol software was soon being placed on every type of computer, and universities and research groups also began using in-house networks known as Local Area Networks or LAN's. These in-house networks then started using Internet Protocol software so one LAN could connect with other LAN's. 

In 1986, one LAN branched out to form a new competing network, called NSFnet (National Science Foundation Network). NSFnet first linked together the five national supercomputer centres, then every major university, and it started to replace the slower Arpanet (which was finally shutdown in 1990).


NSFnet formed the backbone of what we call the Internet today.




Initial ARPA deployment


The initial ARPANET consisted of four IMPs. They were installed at:


1.) UCLA, where Leonard Kleinrock had established a Network Measurement Centre (with an SDS Sigma 7 being the first computer attached to it).


2.) The Stanford Research Institute's Augmentation Research Centre, where Douglas Engelbart had created the ground-breaking NLS system, a very important early hypertext system (with the SDS 940 that ran NLS, named 'Genie', being the first host attached).


3.) UC Santa Barbara (with the Culler-Fried Interactive Mathematics Centre's IBM 360/75, running OS/MVT being the machine attached).


4.) The University of Utah's Graphics Department, where Ivan Sutherland had moved (for a DEC PDP-10 running TENEX).


The first message ever to be sent over the ARPANET (sent over the first host-to-host connection) occurred at 10:30 PM on October 29, 1969 , the connection was established over a 50 kbps line provided by the AT&T telephone company, and a two node ARPANET was born. As is often the case, the first test didn't work flawlessly. It was sent by UCLA student programmer Charley Kline and supervised by UCLA Professor Leonard Kleinrock. The message was sent from the UCLA SDS Sigma 7 Host computer to the SRI SDS 940 Host computer. The message itself was simply the word "login." The "l" and the "o" transmitted without problem but then the system crashed. Hence, the first message on the ARPANET was "lo". They were able to do the full login about an hour later.


The first permanent ARPANET link was established on November 21, 1969, between the IMP at UCLA and the IMP at SRI. By December 5, 1969, the entire 4-node network was connected.



Software and Protocol development


On ARPANET the starting point for host-to-host communication was the 1822 protocol which defined the way that a host sent messages to an ARPANET IMP(Interface Message Processor). The format of the message was designed so that it worked unambiguously with a broad range of computer architectures. The 1822 message consisted of a numeric host address, and a data field. In order for a data message to be sent to another host, the sending host would have to format a data message containing the destination host’s address and the data to be sent. This would then be transmitted through the 1822 hardware interface. The Interface Message Processor (IMP) would see that the message has been delivered to its destination either by delivering to a locally connected host or by delivering it to another IMP. When it is finally delivered then the IMP would send an acknowledgement message to the sending host which is known as a RFNM (ready for next message).


The Arpanet was designed to transmit all 1822 messages reliably or if not then be able to tell the host when a message was lost. Today’s Internet Protocol is unreliable were as the TCP (Transmission control protocol) provides reliability. Despite this the 1822 protocol did not prove itself adequate for juggling multiple connections between different applications which resided on a different single host.

A development which addressed this problem was the NCP (network control program) which provided a standard method to establish a reliable, flow controlled, bi-directional communications link between different processes on different hosts. The NCP interface allowed application software to connect across the ARPANET implementing higher level communication protocols.


This was an early example of the protocol layering concept incorporate into the OSI model (Open Systems Interconnection Basic Reference). By 1983 TCP/IP protocols replaced NCP as the principal protocol of the ARPANET and ARPANET became just one component of the fledgling.

When the ARPANET migrated to the Internet protocols in 1983, the major application protocols migrated along with it.



By 1973, 75% of the ARPANET traffic was email.

File transfer:

Voice traffic:

A Network Voice Protocol specifications was also defined and then implemented, but conference calls over the ARPANET never worked well, for technical reasons By 1973, the File Transfer Protocol specification had been defined and implemented, enabling file transfers over the ARPANET. In 1971, Ray Tomlinson of BBN sent the first network email

Electronic mail is a store and forward [i] method of composing, sending, storing, and receiving message ...




Growth of ARPAnet


The ARPAnet essentially started as a military and academic network to support defence strategies and was restricted, operating between contracted defence companies and University campuses. However once development began many new features and protocols were added so that the ARPAnet went beyond the original range of it's inventors early intentions and this eventually led to the development of the Internet.



In March 1970, the ARPAnet reached the United States East Coast, when an, interface message processors at BBN itself was joined up to the network.

Thereafter, the network grew quickly,

·         9 IMPs by June 1970,

·         13 by December

·         18 by September 1971

·         29 by August 1972

·         40 by September, 1973



At that point, two satellite links, across the Pacific and Atlantic Oceans to Hawaii and Norway, had been added to the network.

From Norway, a terrestrial circuit added an IMP in London to the growing network.

By June 1974, there were 46 IMPs, and the network reached 57 in July, 1975.

By 1981, the number of hosts had grown to 213, with a new host being added approximately every twenty days.



After the ARPAnet had been up and running for several years, ARPA looked for another agency to hand off the network to.

ARPA's primary business was funding cutting-edge research and development, not running a communications utility. Eventually, in July 1975, the network was turned over to the Defense Communications Agency, also part of the Department of Defense.



In 1983, the U.S. military portion of the ARPAnet was broken off as a separate network, the MILNET. Prior to this there were 113 nodes on the ARPAnet. After the split, that number was 68 nodes with the remainder moving to MILNET.



New protocols were needed so that expansion could continue. One of the most important was TCP/IP, which meant that all the new networks could communicate and transmit data to each other.



However the development of the Internet continued and new protocols were introduced, such as HTTP developed at CERN by Tim Berners-Lee and which led to the development of the World Wide Web.



Scientists and programmers have continued to introduce new applications that make the Internet easier to use and navigate. The Internet is now available to everyone who owns a computer and has a phone line connected to a network.



Timeline of ARPAnet






In 1971 saw the start of the use of the non-ruggedized (and therefore significantly lighter) Honeywell 316 as an IMP. It could also be configured as a Terminal IMP (TIP), which added support for up to 63 ASCII serial terminals through a multi-line controller in place of one of the hosts. The 316 featured a greater degree of integration than the 516, which made it less expensive and easier to maintain. The 316 was configured with 40 kB of core memory for a TIP. The size of core memory was later increased, to 32 kB for the IMPs, and 56 kB for TIPs, in 1973.


In 1975, BBN introduced IMP software running on the Pluribusmulti-processor. These appeared in a small number of sites. In 1981, BBN introduced IMP software running on its own C/30 processor product.

The original IMPs and TIPs were phased out as the ARPANET was shut down after the introduction of the NSFNet, but some IMPs remained in service as late as 1989.


Senator Albert Gore began to craft the High Performance Computing and Communication Act of 1991 (commonly referred to as "The Gore Bill") after hearing the 1988 report toward a National Research Network submitted to Congress by a group chaired by UCLA professor of computer science, Leonard Kleinrock, one of the central creators of the ARPANET (the ARPANET, first deployed by Kleinrock and others in 1969, is the predecessor of the Internet). The bill was passed on December 9, 1991 and led to the National Information Infrastructure (NII) which Gore referred to as the "information superhighway."


The ARPANET (Advanced Research Projects Agency Network) developed by ARPA of the United States Department of Defense, was the world's first operational packet switching network, and the predecessor of the global Internet.

Packet switching, now the dominant basis for both data and voice communication worldwide, was a new and important concept in data communications. Previously, data communication was based on the idea of circuit switching, as in the old typical telephone circuit, where a dedicated circuit is tied up for the duration of the call and communication is only possible with the single party on the other end of the circuit.

     With packet switching, a system could use one communication link to communicate with more than one machine by disassembling data into datagraphs, then gather these as packets. Not only could the link be shared (much as a single post box can be used to post letters to different destinations), but each packet could be routed independently of other packets.
























Comments (7)

sam hummel said

at 4:19 pm on Oct 6, 2008

how many of us are here today?

deborah hannan said

at 4:24 pm on Oct 6, 2008

hey me n sian r here now! lol

Andrea Houston said

at 4:29 pm on Oct 6, 2008

so r we

deborah hannan said

at 4:40 pm on Oct 6, 2008

woohoo... lol so is at us sorted... we just add our material to the homepage and thats it sorted?? wbx

Sian Hughes said

at 4:25 pm on Oct 13, 2008

Hey people.. hopefully the group content is completed by the end of the day so maybe we could meet up during the week so we not leaving it too late to add the HMTL tags etc??

Andrea Houston said

at 4:45 pm on Oct 13, 2008

i'll have it done for tomoro. can meet anytime this week

sam hummel said

at 4:48 pm on Oct 13, 2008

There are still a few more areas that need to be added on this page like for example the Creation of arapta net as well as Software and protocol development of arapta net by some of the group members.

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