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X.25
X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee (CCITT, now ITU-T) in a series of drafts and finalized in a publication known as ''The Orange Book'' in 1976.CCITT, Study Group VII, ''Draft Recommendation X-25'', March 1976 This makes it one of the oldest packet-switching communication protocols available; it was developed several years before IPv4 (1981) and the OSI Reference Model (1984). The protocol suite is designed as three conceptual layers, which correspond closely to the lower three layers of the seven-layer OSI model. It also supports functionality not found in the OSI network layer. Networks using X.25 were popular during the late 1970s and 1980s with telecommunications companies and in financial transaction systems such as automated teller machines. An X.25 WAN consists of packet-switching exchange (PSE) nodes a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet Switching
In telecommunications, packet switching is a method of grouping Data (computing), data into ''network packet, packets'' that are transmitted over a digital Telecommunications network, network. Packets are made of a header (computing), header and a payload (computing), payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by an operating system, application software, or protocol suite, higher layer protocols. Packet switching is the primary basis for data communications in computer networks worldwide. In the early 1960s, American computer scientist Paul Baran developed the concept that he called "distributed adaptive message block switching", with the goal of providing a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the United States Department of Defense. His ideas contradicted then-established principles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transpac (network)
In telecommunications, packet switching is a method of grouping data into '' packets'' that are transmitted over a digital network. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by an operating system, application software, or higher layer protocols. Packet switching is the primary basis for data communications in computer networks worldwide. In the early 1960s, American computer scientist Paul Baran developed the concept that he called "distributed adaptive message block switching", with the goal of providing a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the United States Department of Defense. His ideas contradicted then-established principles of pre-allocation of network bandwidth, exemplified by the development of telecommunications in the Bell System. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Data Network
A public data network (PDN) is a network established and operated by a telecommunications administration, or a recognized private operating agency, for the specific purpose of providing data transmission services for the public. The first public packet switching network, RETD, was deployed in 1972 in Spain. "Public data network" was the common name given to the collection of X.25 providers, the first of which was DATAPAC in 1976. The International Packet Switched Service became the first commercial and international packet-switched network in 1978. Their combined networks had large global coverage during the 1980s and into the 1990s. These networks later provided the infrastructure for the early Internet. Description In communications, a PDN is a circuit- or packet-switched network that is available to the public and that can transmit data in digital form. A PDN provider is a company that provides access to a PDN and that provides any of X.25, Frame Relay, or cell relay ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tymnet
Tymnet was an international data communications network headquartered in Cupertino, California that used virtual call packet-switched technology and X.25, SNA/ SDLC, BSC and Async interfaces to connect host computers (servers) at thousands of large companies, educational institutions, and government agencies. Users typically connected via dial-up connections or dedicated asynchronous connections. The business consisted of a large public network that supported dial-up users and a private network that allowed government agencies and large companies (mostly banks and airlines) to build their own dedicated networks. The private networks were often connected via gateways to the public network to reach locations not on the private network. Tymnet was also connected to dozens of other public networks in the United States and internationally via X.25/ X.75 gateways. As the Internet grew and became almost universally accessible in the late 1990s, the need for services such as Tymnet migr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telenet
Telenet was an American commercial packet-switched network which went into service in 1975. It was the first FCC-licensed public data network in the United States. Various commercial and government interests paid monthly fees for dedicated lines connecting their computers and local networks to this backbone network. Free public dialup access to Telenet, for those who wished to access these systems, was provided in hundreds of cities throughout the United States. The original founding company, Telenet Inc., was established by Bolt Beranek and Newman (BBN) and recruited Larry Roberts (former head of the ARPANet) as President of the company, and Barry Wessler. GTE acquired Telenet in 1979. It was later acquired by Sprint and called "Sprintnet". Sprint migrated customers from Telenet to the modern-day Sprintlink IP network, one of many networks composing today's Internet. Telenet had its first offices in downtown Washington, D.C., then moved to McLean, Virginia. It was acqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iberpac
Iberpac (or Red UNO) was the Spain, Spanish packet switched X.25 data network. It was operated by Compañía Telefónica Nacional de España, Telefónica España, the incumbent Spanish telecommunications operator. Iberpac lents its name to Iberpac Plus and Iberpac Básico, the latest X.25 services in Spain. History Red Especial de Transmisión de Datos Iberpac evolved from the Spanish ''Red Especial de Transmisión de Datos'' (RETD), the world's first public data network. Created in 1971, RETD was based on general-purpose UNIVAC 418, Univac 418 III computers. The original ''Red Secundaria de Alto Nivel'' (RSAN) protocols for RETD were custom-developed by Telefónica (then Compañía Telefónica Nacional de España, CTNE) under ARPANET design principles. Project TESYS By 1978, project TESYS (Telefónica, SECOINSA, SITRE) started the development of specific-purpose switching nodes. Some of the design principles of TESYS nodes were advanced for their time (multithreading (computer arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISDN
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance. Prior to ISDN, the telephone system consisted of digital links like T1/ E1 on the long-distance lines between telephone company offices and analog signals on copper telephone wires to the customers, the "last mile". At the time, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rémi Després
Rémi Després (born January 16, 1943) is a French engineer and entrepreneur known for his contributions on data networking. Education In 1961–1963, Rémi Després attended École Polytechnique of Paris, of which he holds an Engineer degree. At UC Berkeley, he received a master's degree in 1967, and a Ph.D degree in 1969, both in the EECS Department. Career From 1963 to 1971 at CNET and UC Berkeley, he specialized in programming languages and time-sharing operating systems. From 1971 to 1980, Rémi Després was in charge of R&D of the French PTT on packet switching. He was one of the leading "innovators who worked across the boundaries of computers and communications" in the 1970s. As such, he introduced the concept of graceful "saturated operation", which was referenced by Bob Kahn and Vint Cerf in their seminal 1974 paper on internetworking, ''"A Protocol for Packet Network Intercommunication".'' He named and formalized the concept of virtual circuits and, with his te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compuserve
CompuServe (CompuServe Information Service, also known by its initialism CIS) was an American online service provider, the first major commercial one in the world – described in 1994 as "the oldest of the Big Three information services (the others are Prodigy and America Online)." It dominated the field during the 1980s and remained a major influence through the mid-1990s. At its peak in the early 1990s, CIS was known for its online chat system, message forums covering a variety of topics, extensive software libraries for most computer platforms, and a series of popular online games, notably '' MegaWars III'' and '' Island of Kesmai''. It also was known for its introduction of the GIF format for pictures and as a GIF exchange mechanism. In 1997, 17 years after H&R Block had acquired CIS, the parent announced its desire to sell the company. A complex deal was worked out with WorldCom acting as a broker, resulting in CIS being sold to AOL. In 2015, Verizon acquired AOL, inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OSI Model
The Open Systems Interconnection model (OSI model) is a conceptual model that 'provides a common basis for the coordination of SOstandards development for the purpose of systems interconnection'. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model partitions the flow of data in a communication system into seven abstraction layers to describe networked communication from the physical implementation of transmitting bits across a communications medium to the highest-level representation of data of a distributed application. Each intermediate layer serves a class of functionality to the layer above it and is served by the layer below it. Classes of functionality are realized in all software development through all and any standardized communication protocols. Each layer in the OSI model has its own well-defined functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
