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Xerox Network Systems
Xerox Network Systems (XNS) is a computer networking protocol suite developed by Xerox within the Xerox Network Systems Architecture. It provided general purpose network communications, internetwork routing and packet delivery, and higher level functions such as a reliable stream, and remote procedure calls. XNS predated and influenced the development of the Open Systems Interconnection (OSI) networking model, and was very influential in local area networking designs during the 1980s. XNS was developed by the Xerox Systems Development Department in the early 1980s, who were charged with bringing Xerox PARC's research to market. XNS was based on the earlier (and equally influential) PARC Universal Packet (PUP) suite from the late 1970s. Some of the protocols in the XNS suite were lightly modified versions of the ones in the Pup suite. XNS added the concept of a network number, allowing larger networks to be constructed from multiple smaller ones, with routers controlling the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Xerox
Xerox Holdings Corporation (, ) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox was the pioneer of the photocopier market, beginning with the introduction of the Xerox 914 in 1959, so much so that the word ''xerox'' is commonly used as a synonym for ''photocopy''. Xerox is headquartered in Norwalk, Connecticut, though it is incorporated in New York (state), New York with its largest group of employees based around Rochester, New York, the area in which the company was founded. As a large developed company, it is consistently placed in the list of Fortune 500 companies. The company purchased Affiliated Computer Services for $6.4 billion in early 2010. On December 31, 2016, Xerox separated its business process service operations, essentially those operations acquired with the purchase of Affiliated Computer Services, into a new publicly traded company, Conduent. Xerox focuses on its docu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ungermann-Bass
Ungermann-Bass, Inc., also known as UB and UB Networks, was a computer networking company in the 1980s to 1990s. Located in Santa Clara, California, UB was the first large networking company independent of any computer manufacturer. Along with competitors 3Com and Sytek, UB was responsible for starting the networking business in Silicon Valley in 1979. UB was founded by Ralph Ungermann and Charlie Bass. John Davidson, vice president of engineering, was one of the creators of NCP, the transport protocol of the ARPANET before TCP. UB specialized in large enterprise networks connecting computer systems and devices from multiple vendors, which was unusual in the 1980s. At that time most network equipment came from computer manufacturers and usually used only protocols compatible with that one manufacturer's computer systems, such as IBM's SNA or DEC's DECnet. Many UB products initially used the XNS protocol suite, including the flagship Net/One, and later transitioned to TCP/ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Routing Information Protocol
The Routing Information Protocol (RIP) is one of the oldest distance-vector routing protocols which employs the hop count as a routing metric. RIP prevents routing loops by implementing a limit on the number of hops allowed in a path from source to destination. The largest number of hops allowed for RIP is 15, which limits the size of networks that RIP can support. RIP implements the split horizon, route poisoning, and holddown mechanisms to prevent incorrect routing information from being propagated. In RIPv1 routers broadcast updates with their routing table every 30 seconds. In the early deployments, routing tables were small enough that the traffic was not significant. As networks grew in size, however, it became evident there could be a massive traffic burst every 30 seconds, even if the routers had been initialized at random times. In most networking environments, RIP is not the preferred choice of routing protocol, as its time to converge and scalability are poo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Header (computing)
In information technology, header is supplemental data placed at the beginning of a block of data being stored or transmitted. In data transmission, the data following the header is sometimes called the ''Payload (computing), payload'' or ''HTML element#body, body''. It is vital that header composition follows a clear and unambiguous specification or format, to allow for parsing. Examples * E-mail header: The text (body) is preceded by header lines indicating sender, recipient, subject, sending time stamp, receiving time stamps of all intermediate and the final mail transfer agents, and much more. * Similar headers are used in Usenet (NNTP) messages, and HTTP headers. * In a data packet sent via the Internet, the data (payload) are preceded by header information such as the sender's and the recipient's IP addresses, the Communications protocol, protocol governing the format of the payload and several other formats. The header's format is specified in the Internet Protocol, see IP h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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MAC Address
A MAC address (short for medium access control address or media access control address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth. Within the Open Systems Interconnection (OSI) network model, MAC addresses are used in the medium access control protocol sublayer of the data link layer. As typically represented, MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator. MAC addresses are primarily assigned by device manufacturers, and are therefore often referred to as the burned-in address, or as an Ethernet hardware address, hardware address, or physical address. Each address can be stored in the interface hardware, such as its read-only memory, or by a firmware mechanism. Many network interfaces, however, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Network Address
A network address is an identifier for a node or host on a telecommunications network. Network addresses are designed to be unique identifiers across the network, although some networks allow for local, private addresses, or locally administered addresses that may not be unique. Special network addresses are allocated as broadcast or multicast addresses. These too are not unique. In some cases, network hosts may have more than one network address. For example, each network interface controller may be uniquely identified. Further, because protocols are frequently layered, more than one protocol's network address can occur in any particular network interface or node and more than one type of network address may be used in any one network. Network addresses can be flat addresses which contain no information about the node's location in the network (such as a MAC address), or may contain structure or hierarchical information for the routing (such as an IP address). Examples Exa ... [...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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Network Protocol
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any 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 predetermined 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 communicat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Internetwork
Internetworking is the practice of interconnecting multiple computer networks. Typically, this enables any pair of hosts in the connected networks to 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 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''. History The first international heterogenous resource sharing network was developed by the computer science department at University College London (UCL) who interconnected the ARPANET with early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Internet Protocol Suite
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). Early versions of this networking model were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA. The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to each protocol's scope of networking. An implementation of the layers for a particular application forms a protocol stack. From lowest to highest, the layers are the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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OSI Model
The Open Systems Interconnection (OSI) model is a reference model developed by the International Organization for Standardization (ISO) that "provides a common basis for the coordination of standards development for the purpose of systems interconnection." In the OSI reference model, the components of a communication system are distinguished in seven abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The model describes communications from the physical implementation of transmitting bits across a transmission medium to the highest-level representation of data of a distributed application. Each layer has well-defined functions and semantics and serves a class of functionality to the layer above it and is served by the layer below it. Established, well-known communication protocols are decomposed in software development into the model's hierarchy of function calls. The Internet protocol suite as defined in and is a model of net ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |