Title: Internet, Networks of networks
Course: Appdate yourself 4t ESO (in English) - Curs 2016/17 > Section: Topic 8 Networks

Internet, Networks of networks

Internet

Internet is a network of networks of all kinds, which is distributed throughout the world, by means of transferring data either through copper wire or via satellite.

Internet has the form of a web which means that communication between two computers can be transferred  by many diverse alternative paths. Its origins come from the military of the United States which developed this technology at the time of the Cold War with the communist block party during the sixties. It was designed on the thesis that communication between computers can easily be transferred through different trams and nodes, even if some sections are damaged due to an enemy attack. This first network was called ARPANET (Advanced Research Projects Agency). Gradually this technology reached its way to civil society, first in university research networks and finally to the public in the nineties.

Communication between a domestic computer and a server. Source: Wikimedia

In order for communication to take place amongst the different networks, computers and operating systems, a protocol called TCP/IP was developed.

The connection between a computer or an internet network is done through a device called a modem, which works as the medium between the local network and the telephone line. This is the function of a domestic router.

Internet access

Internet access is provided by access providers (ISPs, Internet Service Provider) that are usually the same as the telephone companies.

There are different access technologies, the most popular being ADSL (Asymmetric Digital Subscriber Line) which uses copper wire telephone lines. The asymmetry is due to the different transfer rates supported in each of the senses. It is very small when the information goes from the client to the server (uploading information) and, in contrast, is much larger in reverse (downloading information). The transfer speed is not constant and can vary depending on several factors. The nominal speed that access providers give indicates the maximum possible.

There are many applications on the web to measure the instant speed of your internet connection, some of which have nothing to do with your internet provider.  Check out the following examples:  Test ADSL, Speedtest

Activity:  Measure the internet speed connection of your computer.  Try out 2 different applications and compare them.