What is a network that covers a large geographic area such as a city country or the world using a communications channel that combines many types of media?

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INTRODUCTION Computer networking is the engineering discipline concerned with the communication between computer systems or devices. A computer network is any set of computers or devices connected to each other with the ability to exchange data. It is sometimes considered a sub-discipline of telecommunications, computer science, information technology and computer engineering since it relies heavily upon the theoretical and practical application of these scientific and engineering disciplines. There are three types of networks namely: Internet, intranet, and extranet.

A computer network, often simply referred to as a network, is a collection of computers and devices connected by communications channels that facilitates

The major characteristics of LANs, include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10Gb. This is the data transfer rate. IEEE has projects investigating the standardization of 40 and 100Gb. Wide area network A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. It usually uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer. The Internet is considered the largest network in the world. The PSTN (Public Switched Telephone Network) also is an extremely large network that is converging to use Internet technologies, although not necessarily through the public Internet. A Wide Area Network involves communication through the use of a wide range of different technologies. These technologies include Point-to-Point WANs. COMPUTER NETWORKING HARDWARE COMPONENTS.

All networks are

Networks are often classified by their physical or organizational extent or their purpose. Usage, trust level, and access rights differ between these types of networks, outlined below.

Personal Area Network (PAN)

A personal area network (PAN) is a computer network used for communication among computer and information technological devices close to one person. Devices used in a PAN include personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. Home area networks (HANs) are very similar to PANs.

Local Area Network (LAN)

A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node. The defining characteristics of LANs, in contrast to WANs (wide area networks), include their higher data transfer rates, smaller geographic range, and no need for leased telecommunication lines. LANs can be connected to wide area networks by using routers.

Wide Area Network (WAN)

A wide area network (WAN) is a computer network that covers a large geographic area such as a city, country, or even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies.

Storage Area Network (SAN)

A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to make storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear as locally-attached devices to the operating system. A SAN typically has its own network of storage devices that are not accessible through the local area network by other devices.

Campus Area Network (CAN)

A campus area network (CAN) is a computer network made up of an interconnection of LANs within a limited geographical area. The networking equipment (switches, routers) and transmission media (optical fiber, copper plant, Cat5 cabling, etc.) are almost entirely owned by the campus tenant or owner: an enterprise, university, government, etc. In the case of a university campus-based campus network, the network is likely to link a variety of campus buildings -- including, for example, academic colleges or departments, the university library, and student residence halls. CANs are similar to metropolitan area networks (MANs), which usually span cities or large campuses.

Backbone Network

A backbone network is part of a computer network infrastructure that interconnects various pieces of network, providing a path for the exchange of information between different LANs or subnetworks. A backbone can tie together diverse networks in the same building, in different buildings in a campus environment, or over wide areas. Normally, the backbone's capacity is greater than that of the networks connected to it.

A large corporation which has many locations may have a backbone network that ties all of these locations together -- for example, if a server cluster needs to be accessed by different departments of a company which are located at different geographical locations. The equipment which ties these departments together constitute the network backbone. Network performance management, including network congestion, are critical parameters taken into account when designing a network backbone. Backbone networks are similar to enterprise private networks.

Virtual Private Network (VPN)

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The data link layer protocols of the virtual network are said to be tunneled through the larger network when this is the case. One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

Virtual Network

Not to be confused with a Virtual Private Network, a Virtual Network defines data traffic flows between virtual machines within a hypervisor in a virtual computing environment. Virtual Networks may employ virtual security switches, virtual routers, virtual firewalls, and other virtual networking devices to direct and secure data traffic.

The Internet, represented in this photo, is an aggregation of the different computer networks spanning the globe.