A computer network (or data network) is a telecommunications network that allows computers to exchange data.The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the Internet.
Network devices that originate, route and terminate the data are called network nodes.Nodes can include hosts such as servers and personal computers , as well as networking hardware.Two devices are said to be networked when a process in one device is able to exchange information with a process in another device.
Computer networks support applications such as access to the World Wide Web , shared use of application and storage servers , printers , and fax machines, and use of email and instant messaging applications.The remainder of this article discusses local area network technologies and classifies them according to the following characteristics: the physical media used to transmit signals, the communications protocols used to organize network traffic, along with the network's size, its topology and its organizational intent.
Type of computer network
Local area network
A local area network (LAN) is a network that connects computers and devices in a limited geographical area such as a home, school, office building, or closely positioned group of buildings.Each computer or device on the network is a node.Wired LANs are most likely based on Ethernet technology.Newer standards such as ITU-T G.hn also provide a way to create a wired LAN using existing wiring, such as coaxial cables, telephone lines, and power lines.
Metropolitan area network
Metropolitan area network (MAN) is a large computer network that usually spans a city or a large campus.
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.A WAN uses a communications channel that combines many types of media such as telephone lines, cables, and air waves.WAN often makes use of 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 .
Network topology
Network topology is the layout or organizational hierarchy of interconnected nodes of a computer network.
Common layout are:
- A bus network : all nodes are connected to a common medium along this medium.This was the layout used in the original Ethernet , called 10BASE5 and 10BASE2 .
- A star network : all nodes are connected to a special central node.This is the typical layout found in a Wireless LAN , where each wireless client connects to the central Wireless access point .
- A ring network : each node is connected to its left and right neighbour node, such that all nodes are connected and that each node can reach each other node by traversing nodes left- or rightwards.The Fiber Distributed Data Interface (FDDI) made use of such a topology.
- Mesh network: each node is connected to an arbitrary number of neighbours in such a way that there is at least one traversal from any node to any other.
Devices
- Modem
- Network interface card
- Wireless access point
- Rcpeater
- Hup
- Bridge
- Switches
- Router
- Gateway
The advantages of computer networks.
- Ease of communication.
- Hardware together.
- Software together.
- Use of data and information sharing.
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