Contents of Post
- 1 The Internet has one very simple work:
The Internet has one very simple work:
To move computerized information (known as data) from one place to another. That’s it! The machines that make up the Internet treat all the information they handle in exactly the same way. In this respect, the Internet works a bit like the postal service. Letters are simply passed from one place to another, no matter who they are from or what messages they contain. The job of the mail service is to move letters from place to place, not to worry about why people are writing letters in the first place; the same applies to the Internet.
Just like the mail service, the Internet’s simplicity means it can handle many different kinds of information helping people to do many different jobs. It’s not specialized to handle emails, Web pages, chat messages, or anything else: all information is handled equally and passed on in exactly the same way. Because the Internet is so simply designed, people can easily use it to run new “applications”—new things that run on top of the basic computer network. That’s why, when two European inventors developed Skype, a way of making telephone calls over the Net, they just had to write a program that could turn speech into Internet data and back again. No-one had to rebuild the entire Internet to make Skype possible.
Now that we have a (very) high level sense of what the internet is, how exactly does it work? This is where your browser comes into play.
Your browser is what we call a “client application” and what this simply means is that its a program that allows you to make requests to different web sites and respond to the data that those web sites send back. To best explain how this works,
When you type in “http://youmegeek.com” into your browser, your browser somehow needs to know that this URL (i.e. uniform resource locator) actually means the ip address 188.8.131.52 So what the browser does is that it contacts the DNS (domain name service) and looks up the ip address for that url. You can think of the DNS as a phone book (do you kiddies even know what this is anymore??)
Once the ip address is retrieved, your browser attempts to connect to the web server by opening up a socket connection. Without getting into the details, think of this as you physically calling the tall building (i.e. web server) and seeing if they’re still open. If someone responds, then you know they’re open and you’re connected.
Now that your browser and the server have a open connection with each other, your request to a specific article on ESPN can be made. But before your request can be sent over the internet, it has to follow a set of rules that describe how the request must be formatted. These set of rules are known as TCP/IP and the HTTP protocol.
Essentially, think of it like this: in order to travel along the highways and roads of the internet, every request made by your browser and every response sent by a web server must first be chopped up into small packets of data. You can think of your original request as a photo mosaic, and once its been chopped up, each tile represents a packet of data. Aside from containing the binary bits of data, each tile also knows the ip address its supposed to go to and how to reassemble itself once all the packets reach the destination ip address.
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Going back to our example of requesting a specific article on YouMeGeek, the request for the article is chopped up into packets and sent along the highway and roads. Along the way, there are routers (and other similar devices) that basically act as traffic cops and direct the packets to the correct path leading to the ip address.
Once all the packets of data arrive at the web server, the web server will look for the specific article, similar to how you’d look for a file in a cabinet drawer. Once the file has been located, the web server will chop up the response into data packets again, and send them back to your browser.
What is the internet ?
When we talk about the Internet, what we’re actually referring to is an interconnected network of computers (hence, internet). Some of these computers are web servers, which are just specialized computers that contain and serve content from your favorite websites, and others are just the client devices we use everyday, like our laptops, tablets, and mobile phones.
It is made up of millions of computers all over the world that are digitally connected to each other by cable, fibre or wireless links. You can use the internet to browse websites, communicate with people, download pictures and videos, listen to music or do lots of other amazing things.
But have you ever wondered how the internet works?
IP address :
Computers use an IP address (Internet Protocol address) to identify each other. It’s a bit like a postcode that is unique to each computer connected to the internet. An IP address is a set of numbers that might look like this: 184.108.40.206.
A smart device that directs or routes information around the internet. When a data packet arrives the router reads the IP address information and sends the packet along the best route to its destination.
The DNS (Domain Name System) is a set of standards for how computers exchange data on the Internet. The DNS turns a user-friendly domain names like BBC – Homepage into an Internet Protocol (IP) address.
When we send data across the internet, that data goes through each of these four layers in sequence, starting with the application layer. On the receiving end, however, the sequence is reversed. The data you send arrives via the network layer, it then goes through the internet layer to confirm it’s in the right place, the transport layer reassembles all of the data packets, and — finally — it reaches the application layer, and a recipient is able to view the data in an application.
In diagram form, someone sending a message across the internet would look like this:
Now, to ensure we’re all on the same page here, let me make this quick simile: Sending data across a TCP/IP network is like sending a letter through the mail via the postal service.
In the application layer, you’re writing the actual letter that you’re going to send.
In the transport layer, you’re packaging that letter in an envelope.
In the internet layer, you’re writing the address of the recipient on the envelope, as well as your return address.
And finally, in the network layer, you’re putting the letter in the mail so postal workers can deliver it.