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Reliability (computer Networking)
In computer networking, a reliable protocol is a communication protocol that notifies the sender whether or not the delivery of data to intended recipients was successful. Reliability is a synonym for assurance, which is the term used by the ITU and ATM Forum, and leads to fault-tolerant messaging. Reliable protocols typically incur more overhead than unreliable protocols, and as a result, function more slowly and with less scalability. This often is not an issue for unicast protocols, but it may become a problem for reliable multicast protocols. Transmission Control Protocol (TCP), the main protocol used on the Internet, is a reliable unicast protocol; it provides the abstraction of a reliable byte stream to applications. UDP is an unreliable protocol and is often used in computer games, streaming media or in other situations where speed is an issue and some data loss may be tolerated because of the transitory nature of the data. Often, a reliable unicast protocol i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Computer Networking
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Frame Relay
Frame Relay (FR) is a standardized wide area network (WAN) technology that specifies the Physical layer, physical and data link layers of digital telecommunications channels using a packet switching methodology. Frame Relay was originally developed as a simplified version of the X.25 system designed to be carried over the emerging Integrated Services Digital Network (ISDN) networks. X.25 had been designed to operate over normal telephone lines that were subject to noise that would result in lost data, and the protocol featured extensive error correction to address this. ISDN offered dramatically lower error rates, in effect zero, and the extensive error correction overhead was no longer needed. The new protocol suite was essentially a cut-down X.25 with no error correction, leading to lower overhead, better channel efficiency, and often significantly overall higher performance than X.25. Like X.25, Frame Relay is normally used in a circuit switched layout, where connections betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Internet Protocol
The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet. IP has the task of delivering Packet (information technology), packets from the source Host (network), host to the destination host solely based on the IP addresses in the packet Header (computing), headers. For this purpose, IP defines packet structures that encapsulation (networking), encapsulate the data to be delivered. It also defines addressing methods that are used to label the datagram with source and destination information. IP was the connectionless datagram service in the original ''Transmission Control Program'' introduced by Vint Cerf and Bob Kahn in 1974, which was complemented by a connection-oriented service that became the basis for the Transmission Control Protocol (TCP). The Internet protocol suite is therefore often referre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Reliability (computer Networking)
In computer networking, a reliable protocol is a communication protocol that notifies the sender whether or not the delivery of data to intended recipients was successful. Reliability is a synonym for assurance, which is the term used by the ITU and ATM Forum, and leads to fault-tolerant messaging. Reliable protocols typically incur more overhead than unreliable protocols, and as a result, function more slowly and with less scalability. This often is not an issue for unicast protocols, but it may become a problem for reliable multicast protocols. Transmission Control Protocol (TCP), the main protocol used on the Internet, is a reliable unicast protocol; it provides the abstraction of a reliable byte stream to applications. UDP is an unreliable protocol and is often used in computer games, streaming media or in other situations where speed is an issue and some data loss may be tolerated because of the transitory nature of the data. Often, a reliable unicast protocol i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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End-to-end Principle
The end-to-end principle is a design principle in computer networking that requires application-specific features (such as reliability and security) to be implemented in the communicating end nodes of the network, instead of in the network itself. Intermediary nodes (such as gateways and routers) that exist to establish the network may still implement these features to improve efficiency but do not guarantee end-to-end functionality. The essence of what would later be called the end-to-end principle was contained in the work of Donald Davies on packet-switched networks in the 1960s. Louis Pouzin Louis Pouzin (born 20 April 1931) is a French computer scientist and Internet pioneer. He directed the development of the CYCLADES computer network in France the early 1970s, which implemented a novel design for packet communication. He was the ... pioneered the use of the end-to-end strategy in the CYCLADES network in the 1970s. The principle was first articulated explicitly in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ethernet
Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 1983 as IEEE 802.3. Ethernet has since been refined to support higher bit rates, a greater number of nodes, and longer link distances, but retains much backward compatibility. Over time, Ethernet has largely replaced competing wired LAN technologies such as Token Ring, FDDI and ARCNET. The original 10BASE5 Ethernet uses a thick coaxial cable as a shared medium. This was largely superseded by 10BASE2, which used a thinner and more flexible cable that was both less expensive and easier to use. More modern Ethernet variants use Ethernet over twisted pair, twisted pair and fiber optic links in conjunction with Network switch, switches. Over the course of its history, Ethernet data transfer rates have been increased from the original to the lates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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ALOHAnet
ALOHAnet, also known as the ALOHA System, or simply ALOHA, was a pioneering computer networking system developed at the University of Hawaii. ALOHAnet became operational in June 1971, providing the first public demonstration of a wireless packet data network. The ALOHAnet used a new method of medium access, called ''ALOHA random access'', and experimental ultra high frequency (UHF) for its operation. In its simplest form, later known as Pure ALOHA, remote units communicated with a base station (Menehune) over two separate radio frequencies (for inbound and outbound respectively). Nodes did not wait for the channel to be clear before sending, but instead waited for acknowledgement of successful receipt of a message, and re-sent it if this was not received. Nodes would also stop and re-transmit data if they detected any other messages while transmitting. While simple to implement, this results in an efficiency of only 18.4%. A later advancement, Slotted ALOHA, improved the effi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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CYCLADES
The CYCLADES computer network () was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching and, unlike the ARPANET, was explicitly designed to facilitate internetworking. The CYCLADES network was the first to make the hosts responsible for the reliable delivery of data, rather than this being a centralized service of the network itself. Datagrams were exchanged on the network using transport protocols that do not guarantee reliable delivery, but only attempt best-effort. To empower the network leaves the hosts to perform error-correction, the network ensured end-to-end protocol transparency, a concept later to be known as the end-to-end principle. This simplified network design, reduced network latency, and reduced the opportunities for single point failures. The experience with these concepts led to the design of key features of the Internet Protocol in the ARPANET project. The network ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Interface Message Processor
The Interface Message Processor (IMP) was the packet switching node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of gateways, which are known today as routers. An IMP was a ruggedized Honeywell DDP-516 minicomputer with special-purpose interfaces and software. In later years the IMPs were made from the non-ruggedized Honeywell 316 which could handle two-thirds of the communication traffic at approximately one-half the cost. An IMP requires the connection to a host computer via a special bit- serial interface, defined in '' BBN Report 1822''. The IMP software and the ARPA network communications protocol running on the IMPs was discussed in , the first of a series of standardization documents published by what later became the Internet Engineering Task Force (IETF). History The concept of an interface computer for computer networking was first proposed in 1966 by Donald Davies for the NPL network in England ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Oxford University Press
Oxford University Press (OUP) is the publishing house of the University of Oxford. It is the largest university press in the world. Its first book was printed in Oxford in 1478, with the Press officially granted the legal right to print books by decree in 1586. It is the second-oldest university press after Cambridge University Press, which was founded in 1534. It is a department of the University of Oxford. It is governed by a group of 15 academics, the Delegates of the Press, appointed by the Vice Chancellor, vice-chancellor of the University of Oxford. The Delegates of the Press are led by the Secretary to the Delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University Press has had a similar governance structure since the 17th century. The press is located on Walton Street, Oxford, Walton Street, Oxford, opposite Somerville College, Oxford, Somerville College, in the inner suburb of Jericho, Oxford, Jericho. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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BBN Report 1822
The Interface Message Processor (IMP) was the packet switching node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of gateways, which are known today as routers. An IMP was a ruggedized Honeywell DDP-516 minicomputer with special-purpose interfaces and software. In later years the IMPs were made from the non-ruggedized Honeywell 316 which could handle two-thirds of the communication traffic at approximately one-half the cost. An IMP requires the connection to a host computer via a special bit- serial interface, defined in '' BBN Report 1822''. The IMP software and the ARPA network communications protocol running on the IMPs was discussed in , the first of a series of standardization documents published by what later became the Internet Engineering Task Force (IETF). History The concept of an interface computer for computer networking was first proposed in 1966 by Donald Davies for the NPL network in Engla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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ARPANET
The Advanced Research Projects Agency Network (ARPANET) 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, Robert Taylor (computer scientist), Bob Taylor initiated the ARPANET project in 1966 to enable resource sharing between remote computers. Taylor appointed Lawrence Roberts (scientist), 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 the Interface Message Processors (IMPs) for the network to Bolt Berane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |