iGCSE Computer Science - Distance Learning

Tutor Marked Assignment 6
Tutor Marked Assignment 8 (Programming)

The Internet – The Role of The ISP

The internet is made up of a global network of LANs (Local Area Networks) all connected together using routers that allow data to travel between connected devices.

Imagine that you were travelling from Norwich to Nottingham by car. You would have to follow the network of roads between the two cities going via a number of other places on the way.

In the same way as driving between cities, data between two devices on the internet must travel usng the connected routes available, often bouncing between a number of routers before reaching their destination (although in reality this takes just a few seconds).

In order for the two devices to connect, a number of protocols are used. A protocol is a set of rules that governs data transmission and allows the devices to agree on how the data will be transferred. Usually, the data being requested over the internet is connected to a web page, like this one.

ISPs

An ISP or Internet service provider allows a unique user to connect to the Internet by providing a rental of their telecommunication lines. This allows the user to access the Internet either through copper cables, or for faster broadband fibre optic. Mobile ISPs also provide Internet access to our mobile digital devices through the 4G network and now also the 5G network. For mobile devices the G stands for generation with each subsequent generation being faster than the previous one as more bandwidth is provided.

As there are all many different ISPs across the world they all need to communicate with each other as data packets need to be sent globally no matter which ISP the web server belongs to. They do this by connecting using routers which form The Internet.  

The Internet Vs. The WWW

It is important to remember that there is a difference between the Internet and the worldwide web. The Internet was developed many years ago as a way to connect devices together and is the hardware making up a web of interconnected networks which can all talk to each other and share data. The worldwide web is the software that sits on Top of the Internet and allows us to communicate using the HTTP protocol for web pages and their related data. The worldwide web is actually much younger than the Internet and turned 30 years old in 2019. Watch the video below for more information about the history of how the worldwide web came about.

Domain Name System (DNS)

Once a website has been loaded onto the webserver, the users need a way to access the website. They do this using a URL (Uniform Resource Locator).

The sites DNS is a database of all registered URLs which matches them to the IP of the webserver.

Different parts of a site may point to different servers. For example, the website may be stored in one location, email on another, and a database on another. Using the DNS, the same URL can be used for each because of the protocol used.

Activity

Use the online visual Trace Route tool to track how a data packet is transferred between different routers in order to get to it’s destination. Can you tell by looking at the output when the ISP changes?