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Upstream Server
In computer networking, upstream server refers to a server that provides service to another server. In other words, upstream server is a server that is located higher in a hierarchy of servers. The highest server in the hierarchy is sometimes called the origin server—the application server on which a given resource resides or is to be created. The inverse term, downstream server, is rarely used. The terms are exclusively used in contexts where requests and responses move in opposite ways. It is not used when discussing hierarchical routing or hierarchical network topologies, as packets can be transferred both ways. For example, in the domain name system, a name server in a company's local area network often forwards requests to the internet service provider's (ISP's) name servers, instead of resolving the domain name directly — it can be said that the ISP's name servers are upstream to the local server. Conversely, the ISP's servers typically resolve domain names from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Server (computing)
A server is a computer that provides information to other computers called " clients" on a computer network. This architecture is called the client–server model. Servers can provide various functionalities, often called "services", such as sharing data or resources among multiple clients or performing computations for a client. A single server can serve multiple clients, and a single client can use multiple servers. A client process may run on the same device or may connect over a network to a server on a different device. Typical servers are database servers, file servers, mail servers, print servers, web servers, game servers, and application servers. Client–server systems are usually most frequently implemented by (and often identified with) the request–response model: a client sends a request to the server, which performs some action and sends a response back to the client, typically with a result or acknowledgment. Designating a computer as "server-class hardwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hierarchy
A hierarchy (from Ancient Greek, Greek: , from , 'president of sacred rites') is an arrangement of items (objects, names, values, categories, etc.) that are represented as being "above", "below", or "at the same level as" one another. Hierarchy is an important concept in a wide variety of fields, such as architecture, philosophy, design, mathematics, computer science, organizational theory, systems theory, systematic biology, and the social sciences (especially political science). A hierarchy can link entities either directly or indirectly, and either vertically or diagonally. The only direct links in a hierarchy, insofar as they are hierarchical, are to one's immediate superior or to one of one's subordinates, although a system that is largely hierarchical can also incorporate alternative hierarchies. Hierarchical links can extend "vertically" upwards or downwards via multiple links in the same direction, following a path (graph theory), path. All parts of the hierarchy that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application Server
An application server is a server that hosts applications or software that delivers a business application through a communication protocol. For a typical web application, the application server sits behind the web servers. An application server framework is a service layer model. It includes software components available to a software developer through an application programming interface. An application server may have features such as clustering, fail-over, and load-balancing. The goal is for developers to focus on the business logic. Java application servers Jakarta EE (formerly Java EE or J2EE) defines the core set of API and features of Java application servers. The Jakarta EE infrastructure is partitioned into logical containers. *EJB container: Enterprise Beans are used to manage transactions. According to the Java BluePrints, the business logic of an application resides in Enterprise Beans—a modular server component providing many features, including dec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Resource
In computing, a system resource, or simply resource, is any physical or virtual component of limited availability that is accessible to a computer. All connected devices and internal system components are resources. Virtual system resources include files (concretely file handles), network connections (concretely network sockets), and memory areas. Managing resources is referred to as resource management, and includes both preventing resource leaks (not releasing a resource when a process has finished using it) and dealing with resource contention (when multiple processes wish to access a limited resource). Computing resources are used in cloud computing to provide services through networks. Major resource types * Interrupt request (IRQ) lines * Direct memory access (DMA) channels * Port-mapped I/O * Memory-mapped I/O * Locks * External devices * External memory or objects, such as memory managed in native code, from Java; or objects in the Document Object Model (DOM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Engineering Task Force
The Internet Engineering Task Force (IETF) is a standards organization for the Internet standard, Internet and is responsible for the technical standards that make up the Internet protocol suite (TCP/IP). It has no formal membership roster or requirements and all its participants are volunteers. Their work is usually funded by employers or other sponsors. The IETF was initially supported by the federal government of the United States but since 1993 has operated under the auspices of the Internet Society, a non-profit organization with local chapters around the world. Organization There is no membership in the IETF. Anyone can participate by signing up to a working group mailing list, or registering for an IETF meeting. The IETF operates in a bottom-up task creation mode, largely driven by working groups. Each working group normally has appointed two co-chairs (occasionally three); a charter that describes its focus; and what it is expected to produce, and when. It is open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean. The United States asserts sovereignty over five Territories of the United States, major island territories and United States Minor Outlying Islands, various uninhabited islands in Oceania and the Caribbean. It is a megadiverse country, with the world's List of countries and dependencies by area, third-largest land area and List of countries and dependencies by population, third-largest population, exceeding 340 million. Its three Metropolitan statistical areas by population, largest metropolitan areas are New York metropolitan area, New York, Greater Los Angeles, Los Angel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hierarchical Routing
Hierarchical routing is a method of routing in networks that is based on hierarchical addressing. Background Most Transmission Control Protocol/Internet Protocol (TCP/IP) routing is based on a two-level hierarchical routing in which an IP address is divided into a network portion and a host portion. Gateways use only the network portion until an IP datagram reaches a gateway that can deliver it directly. Additional levels of hierarchical routing are introduced by the addition of subnetworks. Description Hierarchical routing is the procedure of arranging routers in a hierarchical manner. A good example would be to consider a corporate intranet. Most corporate intranets consist of a high speed backbone network. Connected to this backbone are routers which are in turn connected to a particular workgroup. These workgroups occupy a unique LAN. The reason this is a good arrangement is because even though there might be dozens of different workgroups, the span (maximum hop count to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Topology
Network topology is the arrangement of the elements (Data link, links, Node (networking), nodes, etc.) of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial Fieldbus, fieldbusses and computer networks. Network topology is the topological structure of a network and may be depicted physically or logically. It is an application of graph theory wherein communicating devices are modeled as nodes and the connections between the devices are modeled as links or lines between the nodes. Physical topology is the placement of the various components of a network (e.g., device location and cable installation), while logical topology illustrates how data flows within a network. Distances between nodes, physical interconnections, transmission rates, or signal types may differ between two different networks, yet their logical topologies may be identica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Domain Name System
The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information with ''domain names'' (identification (information), identification String (computer science), strings) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985. The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over subdomains of their allocated name space to other name servers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Name Server
A name server is a computer application that implements a network service for providing responses to queries against a directory service. It translates an often humanly meaningful, text-based identifier to a system-internal, often numeric identification or addressing component. This service is performed by the server in response to a Communication protocol, service protocol request. An example of a name server is the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet. The most important function of DNS servers is the translation (resolution) of human-memorable domain names and hostnames into the corresponding numeric Internet Protocol (IP) addresses, the second principal name space of the Internet which is used to identify and locate computer systems and resources on the Internet. Domain name server The Internet maintains two principal namespaces: the domain name hierarchyRFC 1034, ''Domain Names—Concepts and Facilities'', P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Area Network
A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, campus, or building, and has its network equipment and interconnects locally managed. LANs facilitate the distribution of data and sharing network devices, such as printers. The LAN contrasts the wide area network (WAN), which not only covers a larger geographic distance, but also generally involves Leased line, leased telecommunication circuits or Internet links. An even greater contrast is the Internet, which is a system of globally connected business and personal computers. Ethernet and Wi-Fi are the two most common technologies used for local area networks; historical network technologies include ARCNET, Token Ring, and LocalTalk. Cabling Most wired network infrastructures utilize Category 5 cable, Category 5 or Category 6 cable, Category 6 twisted pair cabling with RJ45 (telecommunications), RJ45 compatible terminations. This medium provides physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
