A network is a group of devices connected together for the sharing of data and devices. Using network people can communicate with each other across the world at very low cost using services like chat and email. Network can be used to transfer files and information between devices at a very high speed. A single software can be installed on the server and all the clients in the network can use it instead of installing it on every individual PCs, reducing the cost of software. Devices like printers, scanners and other hardware can be shared easily.
Types of Networks
Network Classification is based on the size of the network
Local Area Network or LAN is a network that is confined to a very small area. It is generally limited to a building. LAN networks are easy to establish using inexpensive devices like routers, switches and hubs.
Metropolitan Area Network or MAN connects different LANs together and it covers larger geographic areas, such as cities.
Wide Area Networks or WAN connects larger geographic areas, such as countries and continents. The Internet is the best example of a public WAN.
In a building, there may be so many devices like laptops, desktops and mobile phones connected to each other. This can be called as a LAN. Nodes are usually connected by means of ethernet cable or WIFI.
When these LANs are connected to each other, it is called a MAN. They are connected to each other using coaxial cables or optical fibers.
WAN connects different MANs together and form a Wider Network. They are connected to each other by means of satellite or transoceanic cables.
Topology is the way in which devices are connected in a network
Point to Point Topology
Point-to-point networks contains exactly two nodes connected back to back using a single piece of cable. This is the most simple topology. It can be easily established.
In case of Bus topology, all devices share single communication line or cable. This can only be used in small networks. The failure of the shared communication link can cause total network failure
All nodes in Star topology are connected to a central device, known as hub device. Hub device can be a router, switch or a hub.That is there is a point to point connection between nodes and the hub device.
All the communication goes through hub device.If the hub device fails, the whole network goes down.
In ring topology, each node is connected to exactly two other machines, creating a circular network. Here the information taverse in clockwise direction.Failure of any host results in failure of the whole ring.
Mesh topology is a combination of previously mentioned topologies. In this type of topology, a node is connected to one or multiple nodes which makes it more reliable. There are two types of Mesh.
Here, all nodes have a point-to-point connection to every other node in the network. It is the most reliable network structure among all network topologies.
Here, all the nodes may not have point-to-point connection to other nodes. Number of links on the node depends on the priority of that node in the network. This topology is less costly.