Ad Hoc Computer Network
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Ad Hoc Computer Network
A wireless ad hoc network (WANET) or mobile ad hoc network (MANET) is a decentralized type of wireless network. The network is ad hoc because it does not rely on a pre-existing infrastructure, such as routers in wired networks or access points in wireless networks. Instead, each node participates in routing by forwarding data for other nodes, so the determination of which nodes forward data is made dynamically on the basis of network connectivity and the routing algorithm in use. In the Windows operating system, ad hoc is a communication mode (setting) that allows computers to directly communicate with each other without a router. Wireless mobile ad hoc networks are self-configuring, dynamic networks in which nodes are free to move. Such wireless networks lack the complexities of infrastructure setup and administration, enabling devices to create and join networks "on the fly". Each device in a MANET is free to move independently in any direction, and will therefore change ...
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Wireless Network
A wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks and business installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations. Admin telecommunications networks are generally implemented and administered using radio communication. This implementation takes place at the physical level (layer) of the OSI model network structure. Examples of wireless networks include cell phone networks, wireless local area networks (WLANs), wireless sensor networks, satellite communication networks, and terrestrial microwave networks. History Wireless networks The first professional wireless network was developed under the brand ALOHAnet in 1969 at the University of Hawaii and became operational in June 1971. The first commercial wireless network was the WaveLAN product family, developed by NCR i ...
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PRNET
The Packet Radio Network (PRNET) was a set of early, experimental mobile ad hoc networks whose technologies evolved over time. It was funded by the Advanced Research Projects Agency (ARPA). Major participants in the project included BBN Technologies, Hazeltine Corporation, Rockwell International's Collins division, and SRI International. History ARPA initiated the PRNET project in 1973, funding both theoretical and experimental research. Its goals were outlined in a 1975 paper by Bob Kahn, namely, to investigate the feasibility of using packet-switched, store-and-forward radio communications to provide reliable computer communications in a mobile environment. The earlier ALOHAnet served as an inspiration, but PRNET tackled a significantly harder set of problems, namely, multi-hop communications between mobile vehicles without a central station. In Kahn's initial conception, the overall system design was "predicated upon the existence of an array of low cost repeaters", where he de ...
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Hop (networking)
In wired computer networking, including the Internet, a hop occurs when a packet is passed from one network segment to the next. Data packets pass through routers as they travel between source and destination. The hop count refers to the number of network devices through which data passes from source to destination (depending on routing protocol, this may include the source/destination, that is, the first hop is counted as hop 0 or hop 1). Since store and forward and other latencies are incurred through each hop, a large number of hops between source and destination implies lower real-time performance. Hop count In wired networks, the hop count refers to the number of networks or network devices through which data passes between source and destination (depending on routing protocol, this may include the source/destination, that is, the first hop is counted as hop 0 or hop 1). Thus, hop count is a rough measure of distance between two hosts. For a routing protocol using 1-or ...
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Network Protocols
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols are to co ...
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IEEE 802
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards. The IEEE 802 family of standards has had twenty-four members, numbered 802.1 through 802.24, with a working group of the LMSC devoted to each. However, not all of these working groups are currently active. The IEEE 802 standards are restricted to computer networks carrying variable-size packets, unlike cell relay networks, for example, in which data is transmitted in short, uniformly sized units called cells. Isochronous signal networks, in which data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also outside the scope of the IEEE 802 standards. The number 802 has no significance: it was simply the next number in the sequence that the IEEE used for standards projects. ...
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Laptop
A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper lid and the keyboard on the inside of the lower lid, although 2-in-1 PCs with a detachable keyboard are often marketed as laptops or as having a "laptop mode". Laptops are folded shut for transportation, and thus are suitable for mobile use. They are so named because they can be practically placed on a person's lap when being used. Today, laptops are used in a variety of settings, such as at work, in education, for playing games, web browsing, for personal multimedia, and for general home computer use. As of 2022, in American English, the terms ''laptop computer'' and ''notebook computer'' are used interchangeably; in other dialects of English, one or the other may be preferred. Although the terms ''notebook computers'' or ''notebooks'' or ...
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Personal Computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or technician. Unlike large, costly minicomputers and mainframes, time-sharing by many people at the same time is not used with personal computers. Primarily in the late 1970s and 1980s, the term home computer was also used. Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with the machines. While personal computer users may develop their own applications, usually these systems run commercial software, free-of-charge software ("freeware"), which is most often proprietary, or free and open-source software, which is provided in "ready-to-run", or binary, form. Software for personal computers is typically developed and distributed independently from the hardware or operating system ma ...
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Near-term Digital Radio
The Near-term digital radio (NTDR) program provided a prototype mobile ad hoc network (MANET) radio system to the United States Army, starting in the 1990s. The MANET protocols were provided by Bolt, Beranek and Newman; the radio hardware was supplied by ITT. These systems have been fielded by the United Kingdom as the High-capacity data radio (HCDR) and by the Israelis as the Israeli data radio. They have also been purchased by a number of other countries for experimentation. The NTDR protocols consist of two components: clustering and routing. The clustering algorithms dynamically organize a given network into cluster heads and cluster members. The cluster heads create a backbone; the cluster members use the services of this backbone to send and receive packets. The cluster heads use a link-state routing algorithm to maintain the integrity of their backbone and to track the locations of cluster members. The NTDR routers also use a variant of Open Shortest Path First Ope ...
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SURAN
The Survivable Radio Network (SURAN) project was sponsored by DARPA in the 1980s to develop a set of mobile ad hoc network (MANET) radio-routers, then known as "packet radios". It was a follow-on to DARPA's earlier PRNET project. The program began in 1983 with the following goals: * develop a small, low-cost, low-power radio that would support more sophisticated packet radio protocols than the DARPA Packet Radio project from the 1970s * develop and demonstrate algorithms that could scale to tens of thousands of nodes * develop and demonstrate techniques for robust and survivable packet networking in sophisticated electronic attacks. A follow-on program in 1987, the Low-cost Packet Radio (LPR), attempted further innovations in mobile networking protocols, with design goals including: * management of radio spreading codes for security, and increasing capacity * new queue management and forwarding techniques for spread spectrum channels * scalability based on dynamic clustering BBN ...
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Ray Tomlinson
Raymond Samuel Tomlinson (April 23, 1941 – March 5, 2016) was an American computer programmer who implemented the first email program on the ARPANET system, the precursor to the Internet, in 1971; It was the first system able to send mail between users on different hosts connected to ARPANET. Previously, mail could be sent only to others who used the same computer. To achieve this, he used the @ sign to separate the user name from the name of their machine, a scheme which has been used in email addresses ever since. The Internet Hall of Fame in its account of his work commented "Tomlinson's email program brought about a complete revolution, fundamentally changing the way people communicate". He is credited with the invention of the TCP three-way handshake which underlies HTTP and many other key Internet protocols. Early life and education Tomlinson was born in Amsterdam, New York, but his family soon moved to the small, unincorporated village of Vail Mills, Broadalbin, Ne ...
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Association For Computing Machinery
The Association for Computing Machinery (ACM) is a US-based international learned society for computing. It was founded in 1947 and is the world's largest scientific and educational computing society. The ACM is a non-profit professional membership group, claiming nearly 110,000 student and professional members . Its headquarters are in New York City. The ACM is an umbrella organization for academic and scholarly interests in computer science ( informatics). Its motto is "Advancing Computing as a Science & Profession". History In 1947, a notice was sent to various people: On January 10, 1947, at the Symposium on Large-Scale Digital Calculating Machinery at the Harvard computation Laboratory, Professor Samuel H. Caldwell of Massachusetts Institute of Technology spoke of the need for an association of those interested in computing machinery, and of the need for communication between them. ..After making some inquiries during May and June, we believe there is ample interest to ...
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Bob Kahn
Robert Elliot Kahn (born December 23, 1938) is an American electrical engineer who, along with Vint Cerf, first proposed the Transmission Control Protocol (TCP) and the Internet Protocol (IP), the fundamental communication protocols at the heart of the Internet. In 2004, Kahn won the Turing Award with Vint Cerf for their work on TCP/IP. Background information Kahn was born in New York to parents Beatrice Pauline (née Tashker) and Lawrence Kahn in a Jewish family of unknown European descent. Through his father, he is related to futurist Herman Kahn. After receiving a B.E.E. degree in electrical engineering from the City College of New York in 1960, Kahn went on to Princeton University where he earned a M.A. in 1962 and Ph.D. in 1964, both in electrical engineering. At Princeton, he was advised by Bede Liu and completed a doctoral dissertation titled "Some problems in the sampling and modulation of signals." He first worked at Bolt Beranek and Newman Inc., then in 1972 joine ...
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