A network is basically a set of two or more computers that are linked, so the computers can share resources, such as printers, software, and internet connections. Networked computers can also share files without having to transfer data using a disk or data key. And users of networked computers can also communicate electronically without use of the internet.
There are many types of computer networks, the most important are:
Local-area networks (LANs): is basically a smaller network that’s confined to a relatively small geographic area confined to a school or a building. Within a LAN network, one computer is the file server,this means that it stores all software that controls the network, and it also stores the software that can be shared among computers in the network,the file server is the heart of the LAN.
Metropolitan Area Network (MAN): connect 2 or more LANs together but does not span outside the boundaries of a city, town, or metropolitan area.
Wide Area Networks(WAN): connect larger geographic area, often, smaller LANs are interconnected to form a large WAN, the connection of this type of network is complicated. WANs are normally connected using multiplexers connect local and metropolitan networks to global communications networks like the Internet.
In addition to these types, there are characteristics that are used to categorize different types of networks, such as:
– Protocol: the protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet.
– Architecture: networks can be broadly classified as using either a peer-to-peer or client/server architecture.
Computers on a network are sometimes called nodes and the ways in which they are commonly linked are called topologies.
Topology refers to the shape of a network, or the network’s layout. How different nodes in a network are connected to each other and how they communicate are determined by the network’s topology.
The most common network topologies are: Star, Ring and Bus.
Star: all devices are connected to a central hub. Nodes communicate across the network by passing data through the hub.
Ring: all devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it.
Bus: all devices are connected to a central cable, called the bus.