How does the internet work — Part 1 — A beginners guide
Here’s a very familiar situation— You want to find out something , perhaps directions to a place or a cookie recipe. So you open up your phone and do a Google search for “chocolate chip cookie recipe” , and the results come up in seconds. You send money from a bank in Hong Kong to another bank in Paris instantly. All of this happens in the blink of an eye , and maybe you have wondered what goes under the hood to make this happen. Let me tell you — LOTS!
From the second you enter a website address in your web browser till the second the browser displays the website , hundreds of individual processes and rules take place which enable this to happen. In this series , I’ll try to break down those processes and rules to someone just starting to explore how the internet and networks work.
The Internet
The internet is a collection of interconnected computer networks that span the globe. Think of a computer network as a bunch of computers that are all connected together. They can exchange information between themselves . One computer may have some data stored in it and another computer can access this data. Each computer will have an address that other computers in that network will know , and use to send and request information. All computers in a network will speak the same language which may be different from whats spoken on other networks.
Now, connect all these different computer networks that lie across the world together and you have the internet. Now , there is a problem here , because a computer in “Network A” in London does not know the address of of a computer in “Network B” in New York. They may not even speak the same language. So , there are a set of rules and technologies that enables computers to communicate with computers outside of its own network. A collection of these rules and technologies — also called as “protocols” is what makes the Internet work. Just imagine millions of computers and devices across the world accessing data from each other, all governed by a set of rules to ensure they work together.
Components that make up the internet
There are a lot of parts that makes the internet works. We’ll take a look at a few of them, and learn about more on the way.
Server — A server can be thought of as a computer that has some software enabled on it that allows it to receive requests for a particular information from a client and then sends that information. For example , a file server hosts files that you , the client , would want to download. An email server allows you , the client to send and receive emails.
Client — A client is a computer that has software on it that allows it to send requests for information to a server. When you enter an address into your web browser , your web browser acts as a client . When you send and receive emails from the email app on your phone , it acts as a client requesting information from the email server.
Host and nodes — Any end device in the network is a host. It could be a client or a server. A networks has many components, (also called as nodes) , which pass information along the way between hosts. Take the example of downloading a file. Host A is a client (your phone/computer running a web browser , Firefox/Chrome) located in London. Host B is a file server located in Tokyo. The message from the client to the server passes through many nodes on its journey from London to Tokyo. Your phone/computer and the file server in Tokyo are hosts in this example.
World Wide Web ( WWW) — A collection of information that is accessed using the internet. Although we may use the word “internet” and “world wide web” interchangeably , they are quite different from each other. The “WWW” can be thought of as a way of accessing information on the internet and allows the transfer of that information between hosts through a protocol. The internet is the infrastructure and building block of the world wide web. The “WWW” uses a language known as “HTTP — Hyper text transfer protocol” to access information. Thus , the “WWW” is just a part of the internet, which has a lot of other parts too, like e-mail , file transfer etc.
Web browser — A web browser is typically how we access the world wide web. The browser (Firefox , Chrome , Internet Explorer etc) speaks the same language HTTP used by the WWW. It uses an address known as a URL — Uniform resource locator to access the web. Here’s an example of a URL : http://www.google.com .
This diagram summarizes the concepts discussed in this post. Consider this as the entire internet shrunk down to a few devices. Here , Host A which is a PC and Host B which is a smartphone is trying to access emails and web content from servers in a different network. Host A and Host B are clients here , because they are requesting services from the server. Host C and Host D are servers which receive requests and provides the necessary responses to the clients. The data from hosts in network A to hosts in network B crosses many interconnected network devices (nodes) on its journey, typically routers and switches , which we will discuss in a later article.
I hope a few of you would have gained a bit of insight into how the internet works, at a very basic level. We’ll dive a bit more deep in the next post, where I will discuss a bit more in depth now that we’ve got the basics covered.
