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Open Systems Architecture
Open systems architecture is a system design approach which aims to produce systems that are inherently interoperable and connectable without recourse to retrofit and redesign. Concept Systems design is a process of defining and engineering the architecture, methods, and interfaces necessary to accomplish a goal or fulfill a set of requirements. In open systems architecture, the design includes intentional provisions to make it possible to expand or modify the system at a later stage after initial operation. There is no one specific universal OSA, but it is essential the specific OSA applicable to a system is rigorously defined and documented. For example, in information technology and telecommunication, such design principles lead to open systems. Telecommunications In telecommunication, open systems architecture (OSA) is a standard that describes the layered hierarchical structure, configuration, or model of a communications or distributed data processing system. It enables ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System
A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, structure and purpose and expressed in its functioning. Systems are the subjects of study of systems theory and other systems sciences. Systems have several common properties and characteristics, including structure, function(s), behavior and interconnectivity. Etymology The term ''system'' comes from the Latin word ''systēma'', in turn from Greek language, Greek ''systēma'': "whole concept made of several parts or members, system", literary "composition"."σύστημα" Henry George Liddell, Robert Scott, ''A Greek–English Lexicon'', on Per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Layer
In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers. Functions The network layer provides the means of transferring variable-length network packets from a source to a destination host via one or more networks. Within the service layering semantics of the OSI network architecture, the network layer responds to service requests from the transport layer and issues service requests to the data link layer. Functions of the network layer include: ; Connectionless communication : For example, IP is connectionless, in that a data packet can travel from a sender to a recipient without the recipient having to send an acknowledgement. Connection-oriented protocols exist at other, higher layers of the OSI model. ; Host addressing :Every host in the network must have a unique address that determines where it is. This address is normally assigned from a hierar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-system Environment Reference Model
Open-system environment (OSE) reference model (RM) or ''OSE reference model'' (OSE/RM) is a 1990 reference model for enterprise architecture. It provides a framework for describing open system concepts and defining a lexicon of terms, that can be agreed upon generally by all interested parties. This reference model is meant as an environment model, complementary to the POSIX architecture for open systems. It offers an extensible framework that allows services, interfaces, protocols, and supporting data formats to be defined in terms of nonproprietary specifications that evolve through open (public), consensus-based forums. This reference model served in the 1990s as a basic building block of several technical reference models and technical architectures. In 1996 this reference model was standardized in the ISO/IEC TR 14252 titled "Information technology -- Guide to the POSIX Open System Environment (OSE)". History The development of the open-system environment reference mod ... [...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] |
Architectural Pattern
An architectural pattern is a general, reusable solution to a commonly occurring problem in software architecture within a given context. The architectural patterns address various issues in software engineering, such as computer hardware performance limitations, high availability and minimization of a business risk. Some architectural patterns have been implemented within software frameworks. The use of the word "pattern" in the software industry was influenced by similar concepts as expressed in traditional architecture, such as Christopher Alexander's ''A Pattern Language'' (1977) which discussed the practice in terms of establishing a pattern lexicon, prompting the practitioners of computer science to contemplate their own design lexicon. Usage of this metaphor within the software engineering profession became commonplace after the publication of ''Design Patterns'' (1994) by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides—now commonly known as the "Gang of F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Architecture Of Interoperable Information Systems
Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings or other structures. The term comes ; ; . Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements. The practice, which began in the prehistoric era, has been used as a way of expressing culture for civilizations on all seven continents. For this reason, architecture is considered to be a form of art. Texts on architecture have been written since ancient times. The earliest surviving text on architectural theories is the 1st century AD treatise ''De architectura'' by the Roman architect Vitruvius, according to whom a good building embodies , and (durability, utility, and beauty). Cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure In general, every telecommunications network conceptually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throughput
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel, such as Ethernet or packet radio, in a communication network. The data that these messages contain may be delivered over physical or logical links, or through network nodes. Throughput is usually measured in bits per second (bit/s or bps), and sometimes in data packets per second (p/s or pps) or data packets per time slot. The system throughput or aggregate throughput is the sum of the data rates that are delivered to all terminals in a network. Throughput is essentially synonymous to digital bandwidth consumption; it can be determined numerically by applying the queueing theory, where the load in packets per time unit is denoted as the arrival rate (), and the drop in packets per unit time is denoted as the departure rate (). The throughput of a communication system may be affected by various factors, including the limitations of the underlying analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Link Layer
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer provides the functional and procedural means to transfer data between network entities and may also provide the means to detect and possibly correct errors that can occur in the physical layer. The data link layer is concerned with local delivery of frames between nodes on the same level of the network. Data-link frames, as these protocol data units are called, do not cross the boundaries of a local area network. Inter-network routing and global addressing are higher-layer functions, allowing data-link protocols to focus on local delivery, addressing, and media arbitration. In this way, the data link layer is analogous to a neighborhood traffic cop; it endeavors to arbitrate between parties contending for access to a medium, without con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systems Design
Systems design interfaces, and data for an electronic control system to satisfy specified requirements. System design could be seen as the application of system theory to product development. There is some overlap with the disciplines of system analysis, system architecture and system engineering. Overview If the broader topic of product development "blends the perspective of marketing, design, and manufacturing into a single approach to product development," then design is the act of taking the marketing information and creating the design of the product to be manufactured. Systems design is therefore the process of defining and developing systems to satisfy specified requirements of the user. The basic study of system design is the understanding of component parts and their subsequent interaction with one another. Physical design The physical design relates to the actual input and output processes of the system. This is explained in terms of how data is input into a system, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Layer
In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. The physical layer provides an electrical, mechanical, and procedural interface to the transmission medium. The shapes and properties of the electrical connectors, the frequencies to broadcast on, the line code to use and similar low-level parameters, are specified by the physical layer. Role The physical layer defines the means of transmitting a stream of raw bits over a physical data link connecting network nodes. The bitstream may be grouped into code words or symbols and converted to a physical signal that is transmitted over a transmission medium. The physical layer consists of the electronic circuit transmission technologies of a network. It is a fundamental layer underlying the higher level functions in a network, and can be imple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
