Since the year 1969 internet has grown from four computers to millions of computers. Internet is not owned by a particular person or a company instead it is a collection of small and big networks. When these networks connect to each other then it is called internet. Internet came from the idea of interconnected networks.
First of all let us know how a single computer that uses internet becomes the part of network. For e.g.:- you dial a number from the modem to get connected to internet service provider (ISP). This ISP is connected to other network and this network is further connected to other big networks. So we can say that internet is a collection of networks.
The first high speed backbone was created by national service foundation in the year 1987. This was known as NSFNET. It was T1 line and can connect one hundred and seventy small networks with the speed of 1.544 million bits per second. Further the companies like IBM, Merit and MCI joined with NSF and formed the T3 backbone which can work with the speed of 45 million bits per second.
Backbones are fiber optic trunk lines which consist of many fibers optic cables which are together to enhance the working capacity.
Big communication companies have their own backbone to connect the different areas. In every area there is a POP (point of presence). Here the local users can connect to the network of the particular company. There is not a particular network that controls over it but the big networks connect with each other through NAPâ€™s network access points.
Suppose there are two companies and each had made their own networks for the customer of one company gets connected to the customer of same company but the customer of one company is not connected to the other companyâ€™s customer. So to establish this communication both the companies agree to connect to NAPâ€™s in the different cities.
Networks are completely dependant on NAPâ€™s, backbones and routers to communicate. One thing amazing about the process is that the information or data from one computer goes through many networks and finally reaches to the destination computer in just a fraction of second. Routers are a type of special computers. Their work is to send data from one computer to other along thousands of pathways. It has two functions one is to check the data or information that it should not go to the place where it is not required and ensures that the data is sent to the required destination. So we can say it connects the two networks moreover it prevents the traffic from one network to go onto other unnecessarily and hence protects the networks. As we know that internet is extremely big network made up of several small network. So the use of router is a big necessity.
Every computer on the internet has its own number which is known as internet protocol or IP address. Internet protocol is a language through which computers communicate on the internet. Computers use the binary form of IP address while it is expressed in decimal for us to understand easily.