Early research and development:
76-493: Merging the networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: The PARC Universal Packet ( PUP or PuP , although the original documents usually use Pup ) was one of the two earliest internetworking protocol suites ; it was created by researchers at Xerox PARC in the mid-1970s. (Technically,
152-543: A Request for Quotation (RFQ) was issued for 140 potential bidders. Most computer science companies regarded the ARPA proposal as outlandish, and only twelve submitted bids to build a network; of the twelve, ARPA regarded only four as top-rank contractors. At year's end, ARPA considered only two contractors and awarded the contract to build the network to BBN in January 1969. The initial, seven-person BBN team were much aided by
228-474: A 16-bit socket number. The network number has a particular special value which means 'this network', for use by hosts which do not (yet) know their network number. Unlike TCP/IP, socket fields are part of the full network address in the PUP header, so that upper-layer protocols did not need to implement their own demultiplexing; PUP also supplies packet types (again, unlike IP). Also, an optional 2-byte checksum covers
304-624: A network project. Herzfeld redirected funds in the amount of one million dollars from a ballistic missile defense program to Taylor's budget. Taylor hired Larry Roberts as a program manager in the ARPA Information Processing Techniques Office in January 1967 to work on the ARPANET. Roberts met Paul Baran in February 1967, but did not discuss networks. Roberts asked Frank Westervelt to explore
380-424: A single computer network may be converted into an internetwork by dividing the network into segments and logically dividing the segment traffic with routers and having an internetworking software layer that applications employ. The Internet Protocol is designed to provide an unreliable (not guaranteed) packet service across the network. The architecture avoids intermediate network elements maintaining any state of
456-671: A successor, the Xerox Networking System (XNS), was developed by the Xerox Office Systems Division using many of the ideas of PUP and a globally-unique, 48-bit host identifier (which became the MAC address in DIX v2 and later IEEE 802.3 ) to solve these problems: Internetworking Internetworking is the practice of interconnecting multiple computer networks , such that any pair of hosts in
532-485: A testbed for developing and debugging the 1822 protocol , which was a major undertaking. While they were connected electronically in 1969, network applications were not possible until the Network Control Protocol was implemented in 1970 enabling the first two host-host protocols, remote login ( Telnet ) and file transfer ( FTP ) which were specified and implemented between 1969 and 1973. The network
608-460: A three-way internetworking experiment, which linked a mobile vehicle in PRNET with nodes in the ARPANET, and, via SATNET, to nodes at UCL. The X.25 protocol, on which public data networks were based in the 1970s and 1980s, was supplemented by the X.75 protocol which enabled internetworking. Today the interconnecting gateways are called routers . The definition of an internetwork today includes
684-622: A transatlantic satellite link connected ARPANET to the Norwegian Seismic Array (NORSAR), via the Tanum Earth Station in Sweden, and onward via a terrestrial circuit to a TIP at UCL. UCL provided a gateway for interconnection of the ARPANET with British academic networks, the first international resource sharing network, and carried out some of the earliest experimental research work on internetworking. 1971 saw
760-556: Is somewhat fitting to end on the note that the ARPANET program has had a strong and direct feedback into the support and strength of computer science, from which the network, itself, sprang. Access to the ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). The transatlantic connectivity with NORSAR and UCL later evolved into
836-622: The Gateway Information Protocol (an ancestor of RIP ) is used as both the routing protocol , and for hosts to discover routers. PUP also includes a simple echo protocol at the internetwork layer, similar to IP's ping , but operating at a lower level. To establish a transport connection, two protocols came into play. The first, the Rendezvous and Termination Protocol (RTP) , which was used to initiate communication between two entities, as well as manage and terminate
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#1732773217352912-928: The Honeywell DDP-516 computer, configured with 24 KB of expandable magnetic-core memory , and a 16-channel Direct Multiplex Control (DMC) direct memory access unit. The DMC established custom interfaces with each of the host computers and modems. In addition to the front-panel lamps, the DDP-516 computer also features a special set of 24 indicator lamps showing the status of the IMP communication channels. Each IMP could support up to four local hosts and could communicate with up to six remote IMPs via early Digital Signal 0 leased telephone lines. The network connected one computer in Utah with three in California. Later,
988-514: The Interface Message Processors (IMPs) for the network to Bolt Beranek & Newman (BBN). The design was led by Bob Kahn who developed the first protocol for the network. Roberts engaged Leonard Kleinrock at UCLA to develop mathematical methods for analyzing the packet network technology. The first computers were connected in 1969 and the Network Control Protocol was implemented in 1970, development of which
1064-639: The Internet Protocol replaced earlier protocols on the ARPANET in the early 1980s. To build an internetwork, the following are needed: A standardized scheme to address packets to any host on any participating network; a standardized protocol defining format and handling of transmitted packets; components interconnecting the participating networks by routing packets to their destinations based on standardized addresses. Another type of interconnection of networks often occurs within enterprises at
1140-411: The Internet Protocol . The term internetworking is a combination of the components inter (between) and networking . An earlier term for an internetwork is catenet , a short-form of (con)catenating networks . Internetworking, a combination of the components inter (between) and networking , started as a way to connect disparate types of networking technology, but it became widespread through
1216-506: The SATNET . The ARPANET, SATNET and PRNET were interconnected in 1977. The DoD made TCP/IP the standard communication protocol for all military computer networking in 1980. NORSAR and University College London left the ARPANET and began using TCP/IP over SATNET in 1982. On January 1, 1983, known as flag day , TCP/IP protocols became the standard for the ARPANET, replacing the earlier Network Control Protocol. In September 1984 work
1292-679: The Transmission Control Program for internetworking . As this work progressed, a protocol was developed by which multiple separate networks could be joined into a network of networks; this incorporated concepts pioneered in the French CYCLADES project directed by Louis Pouzin . Version 4 of TCP/IP was installed in the ARPANET for production use in January 1983 after the Department of Defense made it standard for all military computer networking. Access to
1368-552: The University of California, Berkeley , and another for Multics at the Massachusetts Institute of Technology . Taylor recalls the circumstance: "For each of these three terminals, I had three different sets of user commands. So, if I was talking online with someone at S.D.C., and I wanted to talk to someone I knew at Berkeley, or M.I.T., about this, I had to get up from the S.D.C. terminal, go over and log into
1444-495: The link layer of the networking model, i.e. at the hardware-centric layer below the level of the TCP/IP logical interfaces. Such interconnection is accomplished with network bridges and network switches . This is sometimes incorrectly termed internetworking, but the resulting system is simply a larger, single subnetwork , and no internetworking protocol , such as Internet Protocol , is required to traverse these devices. However,
1520-451: The 1970s, ARPA did emphasize the goal of "command and control". According to Stephen J. Lukasik , who was deputy director (1967–1970) and Director of DARPA (1970–1975): The goal was to exploit new computer technologies to meet the needs of military command and control against nuclear threats, achieve survivable control of US nuclear forces, and improve military tactical and management decision making. The first four nodes were designated as
1596-430: The ARPANET 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 to them, were geographically separated from them. The ARPANET used distributed computation and incorporated frequent re-computation of routing tables (automatic routing was technically challenging at the time). These features increased
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#17327732173521672-600: The ARPANET did not exactly share Baran's project's goal, he said his work did contribute to the development of the ARPANET. Minutes taken by Elmer Shapiro of Stanford Research Institute at the ARPANET design meeting of 9–10 October 1967 indicate that a version of Baran's routing method ("hot potato") may be used, consistent with the NPL team's proposal at the Symposium on Operating System Principles in Gatlinburg. Later, in
1748-401: The ARPANET project in 1966 to enable resource sharing between remote computers. Taylor appointed Larry Roberts as program manager. Roberts made the key decisions about the request for proposal to build the network. He incorporated Donald Davies ' concepts and designs for packet switching, and sought input from Paul Baran on dynamic routing. In 1969, ARPA awarded the contract to build
1824-504: The ARPANET was expanded in 1981 when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In the early 1980s, the NSF funded the establishment of national supercomputing centers at several universities and provided network access and network interconnectivity with the NSFNET project in 1986. The ARPANET was formally decommissioned in 1990, after partnerships with
1900-552: The ARPANET was made between Stanford Research Institute (SRI) and UCLA, by SRI programmer Bill Duvall and UCLA student programmer Charley Kline, at 10:30 pm PST on 29 October 1969 (6:30 UTC on 30 October 1969). Kline connected from UCLA's SDS Sigma 7 Host computer (in Boelter Hall room 3420) to the Stanford Research Institute's SDS 940 Host computer. Kline typed the command "login," but initially
1976-722: The ARPANET, the hosts became responsible, as demonstrated in the CYCLADES network. Researchers at Xerox PARC outlined the idea of Ethernet and the PARC Universal Packet (PUP) for internetworking. Research at the National Physical Laboratory in the United Kingdom confirmed establishing a common host protocol would be more reliable and efficient. The ARPANET connection to UCL later evolved into SATNET . In 1977, ARPA demonstrated
2052-473: The Department of Defense allowed the universities to join the network for sharing hardware and software resources. According to Charles Herzfeld, ARPA Director (1965–1967): The ARPANET was not started to create a Command and Control System that would survive a nuclear attack, as many now claim. To build such a system was, clearly, a major military need, but it was not ARPA's mission to do this; in fact, we would have been severely criticized had we tried. Rather,
2128-556: The IMPs (similar to the later concept of routers ), that functioned as gateways interconnecting local resources. Routing, flow control, software design and network control were developed by the BBN team. At each site, the IMPs performed store-and-forward packet switching functions and were interconnected with leased lines via telecommunication data sets ( modems ), with initial data rates of 50 kbit /s . The host computers were connected to
2204-399: The IMPs via custom serial communication interfaces. The system, including the hardware and the packet switching software, was designed and installed in nine months. The BBN team continued to interact with the NPL team with meetings between them taking place in the U.S. and the U.K. As with the NPL network, the first-generation IMPs were built by BBN using a rugged computer version of
2280-465: The SDS 940 crashed after he typed two characters. About an hour later, after Duvall adjusted parameters on the machine, Kline tried again and successfully logged in. Hence, the first two characters successfully transmitted over the ARPANET were "lo". The first permanent ARPANET link was established on 21 November 1969, between the IMP at UCLA and the IMP at the Stanford Research Institute. By 5 December 1969,
2356-474: The availability of any suitable hardware infrastructure, without discussing hardware-specific low-level interfaces, and that a host has access to this local network to which it is connected via a link layer interface. For a period in the late 1980s and early 1990s, the network engineering community was polarized over the implementation of competing protocol suites, commonly known as the Protocol Wars . It
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2432-712: The base for the Xerox Network Systems (XNS) protocol suite; some of the protocols in the XNS suite (such as the Internetwork Datagram Protocol ) were lightly modified versions of the ones in the PUP suite, but others are quite different, reflecting the experience gained with PUP and IP. The main internetwork layer protocol is PUP, which roughly corresponds to the Internet Protocol (IP) layer in TCP/IP. A full PUP network address consists of an 8-bit network number, an 8-bit host number, and
2508-417: The civil and military networks reduced the 113-node ARPANET by 68 nodes. After MILNET was split away, the ARPANET would continue to be used as an Internet backbone for researchers, but be slowly phased out. In 1985, the NSF funded the establishment of national supercomputing centers at several universities and provided network access and network interconnectivity with the NSFNET project in 1986. NSFNET became
2584-708: The concept of the " Intergalactic Computer Network ". Those ideas encompassed many of the features of the contemporary Internet. In October 1963, Licklider was appointed head of the Behavioral Sciences and Command and Control programs at the Defense Department's Advanced Research Projects Agency (ARPA). He convinced Ivan Sutherland and Bob Taylor that this network concept was very important and merited development, although Licklider left ARPA before any contracts were assigned for development. Sutherland and Taylor continued their interest in creating
2660-512: The connected networks can exchange messages irrespective of their hardware-level networking technology. The resulting system of interconnected networks is called an internetwork , or simply an internet . The most notable example of internetworking is the Internet , a network of networks based on many underlying hardware technologies. The Internet is defined by a unified global addressing system , packet format, and routing methods provided by
2736-626: The connection of other types of computer networks such as personal area networks . Catenet , a short-form of (con)catenating networks, is obsolete terminolgy for a system of packet-switched communication networks interconnected via gateways . The term was coined by Louis Pouzin in October 1973 in a note circulated to the International Network Working Group , later published in a 1974 paper " A Proposal for Interconnecting Packet Switching Networks" . Pouzin
2812-505: The connection. The second was the primary transport layer protocol, Byte Stream Protocol (BSP) , which was analogous to TCP . Once RTP had started the connection, BSP took over and managed the data transfer. Like TCP, BSP's semantics and operation were in terms of bytes; this was discarded in favour of packets for the equivalent protocol in XNS, Sequenced Packet Protocol . PUP supported a large number of applications. Some of them, such as Telnet and File Transfer Protocol , were basically
2888-455: The design work on TCP/IP, and laid a foundation for the later XNS protocols. In June and July 1973, Vint Cerf and Bob Kahn organized INWG meetings at Stanford , and Xerox Researchers Bob Metcalfe and John Shoch attended. However, the Xerox attendees were told by a Xerox lawyer that they could not talk about PUP. During design discussions, the Xerox attendees kept pointing out flaws in
2964-435: The developing need to connect two or more local area networks via some sort of wide area network . The first international heterogenous resource sharing network was the 1973 interconnection of the ARPANET with early British academic networks through the computer science department at University College London (UCL). In the ARPANET, the network elements used to connect individual networks were called gateways , but
3040-456: The entire packet . PUP packets are up to 554 bytes long (including the 20 byte PUP header ), and the checksum. This is a smaller packet size than IP, which requires all hosts to support a minimum of 576 bytes (but allows packets of up to 65K bytes, if the hosts support them); individual PUP host pairs on a particular network might use larger packets, but no PUP router is required to handle them. Larger packets can be fragmented. A protocol named
3116-509: The ideas that were suggested, until one of the Stanford researchers blurted out, "You guys have already done this, haven’t you?" John Shoch continued to be involved in the development of TCP/IP . Ed Taft was involved in early discussions about email. The biggest impact of PUP was probably as a key component of the office of the future model first demonstrated at Xerox PARC; that demonstration would not have been anything like as powerful as it
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3192-542: The initial four-node network was established. Elizabeth Feinler created the first Resource Handbook for ARPANET in 1969 which led to the development of the ARPANET directory. The directory, built by Feinler and a team made it possible to navigate the ARPANET. In 1968, Roberts contracted with Kleinrock to measure the performance of the network and find areas for improvement. Building on his earlier work on queueing theory and optimization of packet delay in communication networks, Kleinrock specified mathematical models of
3268-559: The model. The Internet Protocol Suite , also known as the TCP/IP model, was not designed to conform to the OSI model and does not refer to it in any of the normative specifications in Request for Comments and Internet standards . Despite similar appearance as a layered model, it has a much less rigorous, loosely defined architecture that concerns itself only with the aspects of the style of networking in its own historical provenance. It assumes
3344-520: The more modern OSPF and IS-IS . It is still in use as an interior gateway protocol, in small sites with simple requirements. In terms of flaws, the PUP protocol family was not device independent, in modern terminology the IP and MAC layers were combined into a single layer, which made wide-scale adoption difficult. PUP's 8-bit network and 8-bit host could scale to at most 64k machines, before an inter-network bridge or gateway would be needed. For this reason,
3420-417: The name PUP only refers to the internetwork-level protocol, but it is also applied to the whole protocol suite.) The entire suite provided routing and packet delivery, as well as higher-level functions such as a reliable byte stream , along with numerous applications. The PUP protocol was created in roughly the same time frame as the earliest parts of the development of TCP/IP for the Internet and also
3496-587: The network, in part, to allow ARPA-sponsored researchers at various corporate and academic locales to utilize computers provided by ARPA, and, in part, to quickly distribute new software and other computer science results. Taylor had three computer terminals in his office, each connected to separate computers, which ARPA was funding: one for the System Development Corporation (SDC) Q-32 in Santa Monica , one for Project Genie at
3572-566: The network. Instead, this function is assigned to the endpoints of each communication session. To transfer data reliably, applications must utilize an appropriate transport layer protocol, such as Transmission Control Protocol (TCP), which provides a reliable stream . Some applications use a simpler, connection-less transport protocol, User Datagram Protocol (UDP), for tasks which do not require reliable delivery of data or that require real-time service, such as video streaming or voice chat. Two architectural models are commonly used to describe
3648-402: The other terminal and get in touch with them. I said, 'Oh Man!', it's obvious what to do: If you have these three terminals, there ought to be one terminal that goes anywhere you want to go. That idea is the ARPANET". Donald Davies' work caught the attention of ARPANET developers at Symposium on Operating Systems Principles in October 1967. He gave the first public presentation, having coined
3724-615: The performance of packet-switched networks, which underpinned the development of the ARPANET as it expanded rapidly in the early 1970s. Roberts engaged Howard Frank to consult on the topological design of the network. Frank made recommendations to increase throughput and reduce costs in a scaled-up network. By March 1970, the ARPANET reached the East Coast of the United States, when an IMP at BBN in Cambridge, Massachusetts
3800-564: The protocols and methods used in internetworking. The Open System Interconnection (OSI) reference model was developed under the auspices of the International Organization for Standardization (ISO) and provides a rigorous description for layering protocol functions from the underlying hardware to the software interface concepts in user applications. Internetworking is implemented in the Network Layer (Layer 3) of
3876-518: The questions of message size and contents for the network, and to write a position paper on the intercomputer communication protocol including “conventions for character and block transmission, error checking and re-transmission, and computer and user identification." In April 1967, ARPA held a design session on technical standards. The initial standards for identification and authentication of users, transmission of characters, and error checking and retransmission procedures were discussed. Roberts' proposal
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#17327732173523952-510: The same protocols as used on the ARPANET (much as occurred with the TCP/IP suite). Others were novel, including protocols for printer spooling, copying disk packs, page-level remote access to file servers, name lookup, remote management, etc. (although some of these capabilities had been seen before, e.g. the ARPANET already made heavy use of remote management for controlling the Interface Message Processors (IMPs) which made it up). PUP showed that internetworking ideas were feasible, influenced
4028-476: The same time period as the early Ethernet local area network at PARC. The fundamental design of the PUP suite was substantially complete by 1974. PUP was designed to connect the Ethernet to the ARPANET , which was a forerunner to TCP/IP and the Internet . It was primarily designed by Robert Metcalfe , David Boggs , Charles P. Thacker , Butler Lampson and John Shoch . In the 1980s Xerox used PUP as
4104-442: 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 Interface Processor (TIP), which provided terminal server 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
4180-611: The survivability of the network in the event of significant interruption. Furthermore, the ARPANET was designed to survive subordinate network losses. However, the Internet Society agrees with Herzfeld in a footnote in their online article, A Brief History of the Internet : It was from the RAND study that the false rumor started, claiming that the ARPANET was somehow related to building a network resistant to nuclear war. This
4256-466: The technical specificity of their response to the ARPA RFQ, and thus quickly produced the first working system. The "IMP guys" were led by Frank Heart ; the theoretical design of the network was led by Bob Kahn ; the team included Dave Walden , Severo Ornstein , William Crowther and several others. The BBN-proposed network closely followed Roberts' ARPA plan: a network composed of small computers,
4332-400: The telecommunication and computer industry had assured private sector expansion and commercialization of an expanded worldwide network, known as the Internet. Historically, voice and data communications were based on methods of circuit switching , as exemplified in the traditional telephone network, wherein each telephone call is allocated a dedicated end-to-end electronic connection between
4408-585: The term packet switching , in August 1968 and incorporated it into the NPL network in England. The NPL network and ARPANET were the first two networks in the world to implement packet switching. Roberts said the computer networks built in the 1970s were similar "in nearly all respects" to Davies' original 1965 design. In February 1966, Bob Taylor successfully lobbied ARPA's Director Charles M. Herzfeld to fund
4484-456: The term has been deprecated in this context, because of possible confusion with functionally different devices. By 1973-4, researchers in France, the United States, and the United Kingdom had worked out an approach to internetworking where the differences between network protocols were hidden by using a common internetwork protocol, and instead of the network being responsible for reliability, as in
4560-599: The theoretical model of distributed adaptive message block switching . However, the telecommunication establishment rejected the development in favor of existing models. Donald Davies at the United Kingdom's National Physical Laboratory (NPL) independently arrived at a similar concept in 1965. The earliest ideas for a computer network intended to allow general communications among computer users were formulated by computer scientist J. C. R. Licklider of Bolt Beranek and Newman (BBN), in April 1963, in memoranda discussing
4636-525: The two communicating stations. The connection is established by switching systems that connected multiple intermediate call legs between these systems for the duration of the call. The traditional model of the circuit-switched telecommunication network was challenged in the early 1960s by Paul Baran at the RAND Corporation , who had been researching systems that could sustain operation during partial destruction, such as by nuclear war. He developed
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#17327732173524712-420: Was a pioneer in packet-switching technology and founder of the CYCLADES network, at a time when network meant what is now called a local area network . Catenet was the concept of linking these networks into a network of networks with specifications for compatibility of addressing and routing. The term catenet was gradually displaced by the short-form of the term internetwork, internet (lower-case i ), when
4788-449: Was added in 1970, although considerations of cost and IMP processing power meant this capability was not actively used. Larry Roberts saw the ARPANET and NPL projects as complementary and sought in 1970 to connect them via a satellite link. Peter Kirstein 's research group at University College London (UCL) was subsequently chosen in 1971 in place of NPL for the UK connection. In June 1973,
4864-473: Was completed on restructuring the ARPANET giving U.S. military sites their own Military Network ( MILNET ) for unclassified defense department communications. Both networks carried unclassified information and were connected at a small number of controlled gateways which would allow total separation in the event of an emergency. MILNET was part of the Defense Data Network (DDN). Separating
4940-606: 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. The ARPANET was demonstrated at the International Conference on Computer Communications in October 1972. In 1975, BBN introduced IMP software running on the Pluribus multi-processor . These appeared in a few sites. In 1981, BBN introduced IMP software running on its own C/30 processor product. ARPA
5016-549: Was connected to the network. Thereafter, the ARPANET grew: 9 IMPs by June 1970 and 13 IMPs by December 1970, then 18 by September 1971 (when the network included 23 university and government hosts); 29 IMPs by August 1972, and 40 by September 1973. By June 1974, there were 46 IMPs, and in July 1975, the network numbered 57 IMPs. By 1981, the number was 213 host computers, with another host connecting approximately every twenty days. Support for inter-IMP circuits of up to 230.4 kbit/s
5092-606: Was declared operational in 1971. Network traffic began to grow once email was established at the majority of sites by around 1973. The initial ARPANET configuration linked UCLA , ARC , UCSB , and the University of Utah School of Computing . The first node was created at UCLA, where Leonard Kleinrock could evaluate network performance and examine his theories on message delay . The locations were selected not only to reduce leased line costs but also because each had specific expertise beneficial for this initial implementation phase: The first successful host-to-host connection on
5168-585: Was intended to fund advanced research. The ARPANET was a research project that was communications-oriented, rather than user-oriented in design. Nonetheless, in the summer of 1975, operational control of the ARPANET passed to the Defense Communications Agency . At about this time, the first ARPANET encryption devices were deployed to support classified traffic. The ARPANET Completion Report , written in 1978 and published in 1981 jointly by BBN and DARPA , concludes that: ... it
5244-475: Was led by Steve Crocker at UCLA and other graduate students, including Jon Postel and others. The network was declared operational in 1971. Further software development enabled remote login and file transfer , which was used to provide an early form of email . The network expanded rapidly and operational control passed to the Defense Communications Agency in 1975. Bob Kahn moved to DARPA and, together with Vint Cerf at Stanford University , formulated
5320-423: Was never true of the ARPANET, but was an aspect of the earlier RAND study of secure communication. The later work on internetworking did emphasize robustness and survivability, including the capability to withstand losses of large portions of the underlying networks. Paul Baran , the first to put forward a theoretical model for communication using packet switching, conducted the RAND study referenced above. Though
5396-434: Was presented at the inaugural Symposium on Operating Systems Principles in October 1967. Donald Davies' work on packet switching and the NPL network, presented by a colleague ( Roger Scantlebury ), and that of Paul Baran, came to the attention of the ARPA investigators at this conference. Roberts applied Davies' concept of packet switching for the ARPANET, and sought input from Paul Baran on dynamic routing. The NPL network
5472-461: Was that all mainframe computers would connect to one another directly. The other investigators were reluctant to dedicate these computing resources to network administration. After the design session, Wesley Clark proposed minicomputers should be used as an interface to create a message switching network. Roberts modified the ARPANET plan to incorporate Clark's suggestion and named the minicomputers Interface Message Processors (IMPs). The plan
5548-642: Was the first wide-area packet-switched network with distributed control and one of the first computer networks to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet . The ARPANET was established by the Advanced Research Projects Agency (now DARPA) of the United States Department of Defense . Building on the ideas of J. C. R. Licklider , Bob Taylor initiated
5624-425: Was unclear which of the OSI model and the Internet protocol suite would result in the best and most robust computer networks. ARPANET Early research and development: Merging the networks and creating the Internet: Commercialization, privatization, broader access leads to the modern Internet: Examples of Internet services: The Advanced Research Projects Agency Network ( ARPANET )
5700-480: Was using line speeds of 768 kbit/s, and the proposed line speed for the ARPANET was upgraded from 2.4 kbit/s to 50 kbit/s. By mid-1968, Roberts and Barry Wessler wrote a final version of the IMP specification based on a Stanford Research Institute (SRI) report that ARPA commissioned to write detailed specifications describing the ARPANET communications network. Roberts gave a report to Taylor on 3 June, who approved it on 21 June. After approval by ARPA,
5776-401: Was without all the capabilities that a working internetwork provided. The Gateway Information Protocol's descendant, RIP (with minor modifications to carry the addresses of any protocol family), remains in use today in other protocol suites, including TCP/IP. One version of RIP served as one of the initial so-called interior gateway protocols for the growing Internet , before the arrival of
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