ARPANET - Wikipedia.The Advanced Research Projects Agency Network (ARPANET) was an early packet switchingnetwork and the first network to implement the protocol suite. Free Mp3 Download Lazy Dougie . Book Title. FireSIGHT System User Guide Version 5.4.1. Chapter Title. Using Objects and Security Zones. PDF - Complete Book (18.11 MB) PDF - This. Help in finding attorneys, therapists, educational consultants, psychologists, diagnosticians, health care providers, tutors, coaches, and advocates for children with. Green computing, the study and practice of efficient and eco-friendly computing resources, is now under the attention of not only environmental organizations, but. TCP/IP. Both technologies became the technical foundation of the Internet. ARPANET was initially founded by the Advanced Research Projects Agency (ARPA) of the United States Department of Defense.[1][2][3][4][5]The packet switching methodology employed in the ARPANET was based on concepts and designs by British scientist Donald Davies,[1. Americans Paul Baran, Lawrence Roberts and Leonard Kleinrock.[1. The TCP/IP communications protocols were developed for ARPANET by computer scientists. Robert Kahn and Vint Cerf, incorporating concepts from the French CYCLADES project directed by Louis Pouzin. As the project progressed, protocols for internetworking were developed by which multiple separate networks could be joined into a network of networks. Access to the ARPANET was expanded in 1. National Science Foundation (NSF) funded the Computer Science Network (CSNET). In 1. 98. 2, the Internet protocol suite (TCP/IP) was introduced as the standard networking protocol on the ARPANET. In the early 1. 98. NSF funded the establishment of national supercomputing centers at several universities, and provided interconnectivity in 1. NSFNET project, which also created network access to the supercomputer sites in the United States from research and education organizations. ARPANET was decommissioned in 1. History[edit]Background[edit]The earliest ideas for a computer network intended to allow general communications among computer users were formulated by computer scientist. J. C. R. Licklider, who in 1. ARPA Information Processing Techniques Office. In April 1. 96. 3, he circulated an office memoranda discussing the concept of the "Intergalactic Computer Network". Those ideas encompassed many of the features of the contemporary Internet. In October 1. 96. 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 his successors, 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.[1. Sutherland and Taylor continued their interest in creating 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.[1. 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- 3. Santa Monica, one for Project Genie at 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 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".[1. Meanwhile, since the early 1. Paul Baran at the RAND Corporation had been researching systems that could survive nuclear war and published the idea of distributed adaptive message block switching in 1. Donald Davies at the United Kingdom's National Physical Laboratory (NPL) independently invented the same concept in 1. He gave the first public demonstration, having coined the term packet switching, on 5 August 1. NPL network in England.[1. The NPL network followed by ARPANET were the first two networks in the world to use packet switching,[1. Prior to the advent of this concept of packet switching, today the dominant basis for data communications worldwide, both voice and data communications had been based on the idea of circuit switching, as in the traditional telephone circuit, wherein each telephone call is allocated a dedicated, end to end, electronic connection between the two communicating stations.Such stations might be telephones or computers. . The (temporarily) dedicated line typically comprises many intermediary lines which are assembled into a chain that stretches all the way from the originating station to the destination station. With packet switching, a data system could use a single communication link to communicate with more than one machine by collecting data into datagrams and transmitting these as packets onto the attached network link, as soon as the link becomes idle. Thus, not only can the link be shared, much as a single post box can be used to post letters to different destinations, but each packet can be routed independent of other packets.[2. Creation[edit]Bob Taylor convinced ARPA's Director Charles M. Herzfeld to fund a network project in February 1. Herzfeld transferred a million dollars from a ballistic missile defense program to Taylor's budget.[2. Taylor hired Larry Roberts as a program manager in the ARPA Information Processing Techniques Office in January 1. ARPANET. In April 1. Roberts 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. At the meeting, Wesley Clark proposed minicomputers called Interface Message Processors (IMPs) should be used to interface to the network rather than the large mainframes that would be the nodes of ARPANET. Roberts modified the ARPANET plan to incorporate Clarkâs suggestion. The plan was presented at the ACM Symposium in Gatlinburg, Tennessee, in October 1. Donald Davies' work on packet switching and the NPL network, presented by a colleague (Roger Scantlebury), came to the attention of ARPANET developers at this conference.[6][7] Roberts applied Davies' concept of packet switching for the ARPANET,[2. Paul Baran and Leonard Kleinrock. Building on his earlier work on queueing theory, Kleinrock modelled the performance of packet- switched networks, which underpinned the development of the ARPANET.[6][8] The NPL network was using line speeds of 7. ARPANET was upgraded from 2. By mid- 1. 96. 8, Roberts had prepared a complete plan for the computer network and gave a report to Taylor on June 3, who approved it on June 2. After approval by ARPA, a Request for Quotation (RFQ) was issued for 1. 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 Technologies on 7 April 1. The initial, seven- person BBN team were much aided by the technical specificity of their response to the ARPA RFQ, and thus quickly produced the first working system. This team was led by Frank Heart and included Robert Kahn. The BBN- proposed network closely followed Roberts' ARPA plan: a network composed of small computers called Interface Message Processors (or IMPs), similar to the later concept of routers, that functioned as gateways interconnecting local resources. 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 5. The host computers were connected to the IMPs via custom serial communication interfaces. The system, including the hardware and the packet switching software, was designed and installed in nine months.[2. The BBN team continued to interact with the NPL team.[9][3. The first- generation IMPs were built by BBN Technologies using a rugged computer version of the Honeywell. DDP- 5. 16 computer configured with 2. KB of expandable magnetic- core memory, and a 1. Direct Multiplex Control (DMC) direct memory access unit.[3. The DMC established custom interfaces with each of the host computers and modems. In addition to the front- panel lamps, the DDP- 5. IMP communication channels. Each IMP could support up to four local hosts, and could communicate with up to six remote IMPs via leased lines. The network connected one computer in Utah with three in California.
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