Computer Networks

Computer Networks is a method used to connect computers with each other and with other external devices such as printers and routers. Computer Networks are extremely useful, as they allow users to communicate with each other over large distances the Internet is an example of such networks.

Devices in a computer networks are connected in various patterns called topologies. In these topologies the word "node" is used to indicate a device in the network.
There are different types of topologies including:

Bus topology:
Where all the devices are connected using a single cable. It is not a very practical topology to use, as if one device went down the whole network will stop working.
However, it is economic as only one cable is needed.

Star toplogy:
All the devices in the network are linked to a device in the centre. This way if one device went down the rest will still be working.

Ring/Collapsed ring topology:
In this topology, all the devices are connected to each other using a single cable like the Bus, but the two ends remain connected to each other, so that if a device went down, it is still possible for other devices to remain connected.

Computer networks can be classified according to their coverage area such as:
Local Area Network (LAN):
It is of the simplest types of networks that is available over a small range. An example of a LAN is a router connected to several devices at a house.
Metropolitan Area Network (MAN):
They serve users within a specific area of a country or a city or even a university campus.
Wide Area Network (WAN):
They cover large areas, and are connected using radio waves or via telephone networks.

These networks can also be classified according to their accessability :

An inranet is a private network that can be used among people working within an organization.
An extranet is an intranet that is made accessible to people outside the organization such as costumers and suppliers.
An internet, is a type of network that has a number of smaller networks connected within. The Internet (with capital I) we commonly use is actually a set of internet networks connected together.

Computers usually use protocols( which can be defined as : "a set of rules or procedures for transmitting data between devices " ) such as TCP/IP are the mostly used in computer operating systems basically because of their intelligence, robust, compatibility


Questions :

1- Are topolgies such as Bus and Star still used till now?

2- Can the internet be replaced by an alternative network one day?

3- What are other examples of an internet other than the "Internet" ?